aklow labs·chess

SonnetvsHaiku

0-1 · checkmate · 86 Halbzuege · $3.0550 Kosten · 1.545 in / 544.953 out · Langfuse-Trace ↗

Ply 86 / 86

Halbzuege (86)

  1. 1.e4Sonnet669 tok · $0.0099 · 35247ms
    • 1. Observe0 tok · 0ms

      Halbzug 1, Weiss am Zug. Phase: Eroeffnung. Material gleich. Legale Zuege: 20. Criticality: 0.30.

      • material-counter0ms
    • 2. Recall Position0 tok · 9ms

      recall: 5 similar position(s) found (limit=5).

      • nex_search9ms
    • 3. Recall Opponent0 tok · 5ms

      No pattern found for chess-haiku-tm (tag=chess-haiku-tm) — mandatory run documented.

      • nex_entity_search5ms
    • 4. Research0 tok · 0ms · skipped

      research: opening_explorer + web_search both disabled — pure memory-only opening plan.

    • 5. Plan230 tok · 16256ms · claude-sonnet-4-6 · $0.0034

      Phase: opening. Establish central pawn presence on e4 or d4, then develop knights to f3/c3, followed by bishops, and castle kingside by move 6-7. Build a solid classical center with sound piece development and early cast…

      • llm.plan16256ms · $0.0034
      full reasoning
      Phase: opening. Establish central pawn presence on e4 or d4, then develop knights to f3/c3, followed by bishops, and castle kingside by move 6-7. Build a solid classical center with sound piece development and early castling to keep king safe, then outplay from a structurally superior middlegame position. Critical: No opponent threats yet — full freedom of choice; Memory heuristic: central control (e4/d4) is the highest-priority first move; Memory heuristic: knights before bishops — Nf3 follows the first pawn move naturally; Avoid early queen development (no reason to deviate from this); Pawn structure integrity: no premature pawn moves that create weaknesses.
    • 6. Candidates243 tok · 9398ms · claude-sonnet-4-6 · $0.0036

      Candidates: e4 (Central control heuristic #1: e4 maximizes central presence and opens lines for bishop and queen.) | d4 (Central control heuristic #1 (alt): d4 establishes solid queen-pawn center, enabling sound classica…

      • chess.js.legal_moves0ms
      • llm.candidates9394ms · $0.0036
      full reasoning
      Candidates: e4 (Central control heuristic #1: e4 maximizes central presence and opens lines for bishop and queen.) | d4 (Central control heuristic #1 (alt): d4 establishes solid queen-pawn center, enabling sound classical structure.) | Nf3 (Knights before bishops heuristic #2: Nf3 develops naturally, controls e5/d4, delays pawn commitment.)
    • 7. Verify0 tok · 2ms

      Alle 3 Kandidaten legal. cloud_eval disabled (default).

      • chess.js.legal_recheck0ms
    • 8. Reflect196 tok · 9391ms · claude-sonnet-4-6 · $0.0029

      Final pick: e4 — Central control heuristic #1: e4 seizes maximum central space immediately, opens diagonals for Bc4 and the queen, and leads directly into classical 1.e4 structures where White dictates tempo from move on…

      • llm.reflect9390ms · $0.0029
      full reasoning
      Final pick: e4 — Central control heuristic #1: e4 seizes maximum central space immediately, opens diagonals for Bc4 and the queen, and leads directly into classical 1.e4 structures where White dictates tempo from move one.. Rejected: d2d4, g1f3.
    • 9. Commit0 tok · 0ms

      Commit e4 (e2e4).

  2. 2...d5Haiku6.358 tok · $0.0317 · 84814ms
    • 1. Observe0 tok · 0ms

      Halbzug 2, Schwarz am Zug. Phase: Eroeffnung. Material gleich. Legale Zuege: 20. Criticality: 0.30.

      • material-counter0ms
    • 2. Recall Position0 tok · 14ms

      recall: 5 similar position(s) found (limit=5).

      • nex_search14ms
    • 3. Recall Opponent0 tok · 17ms

      No pattern found for chess-sonnet-tm (tag=chess-sonnet-tm) — mandatory run documented.

      • nex_entity_search17ms
    • 4. Research0 tok · 0ms · skipped

      research: opening_explorer + web_search both disabled — pure memory-only opening plan.

    • 5. Plan1427 tok · 21255ms · claude-haiku-4-5 · $0.0071

      Phase: opening. Contest White's e4 with principled central response. Develop knights (f6, c6) before bishops. Maintain flexible pawn structure; avoid early queen moves that lose tempo. Reach middlegame with equal materia…

      • llm.plan21255ms · $0.0071
      full reasoning
      Phase: opening. Contest White's e4 with principled central response. Develop knights (f6, c6) before bishops. Maintain flexible pawn structure; avoid early queen moves that lose tempo. Reach middlegame with equal material, sound pawn structure, and safely centralized pieces (knights and bishops on natural squares). Critical: White's e4 occupies key central square and claims space; Early queen development invites tempo loss via piece attacks; Knight development to f6/c6 is forcing and safe.
    • 6. Candidates2945 tok · 31758ms · claude-haiku-4-5 · $0.0147

      Candidates: d5 (Contests e4 immediately; Scandinavian structure gives Black dynamic counterplay and central initiative.) | e5 (Symmetric center establishment; leads to classical main-lines with solid pawn structure.) | N…

      • chess.js.legal_moves0ms
      • llm.candidates31756ms · $0.0147
      full reasoning
      Candidates: d5 (Contests e4 immediately; Scandinavian structure gives Black dynamic counterplay and central initiative.) | e5 (Symmetric center establishment; leads to classical main-lines with solid pawn structure.) | Nc6 (Sound development supporting center; prepares d5 or e5 pushes, maintains tactical coordination.)
    • 7. Verify0 tok · 1ms

      Alle 3 Kandidaten legal. cloud_eval disabled (default).

      • chess.js.legal_recheck0ms
    • 8. Reflect1986 tok · 31757ms · claude-haiku-4-5 · $0.0099

      Final pick: d5 — d5 forces immediate center conflict. After 2.exd5, Black recovers with dynamic counterplay. Contests e4 directly, maintains tactical initiative.. Rejected: e7e5, b8c6.

      • llm.reflect31756ms · $0.0099
    • 9. Commit0 tok · 0ms

      Commit d5 (d7d5).

  3. 3.exd5Sonnet762 tok · $0.0113 · 31626ms
    • 1. Observe0 tok · 0ms

      Halbzug 3, Weiss am Zug. Phase: Eroeffnung. Material gleich. Legale Zuege: 31. Criticality: 0.30.

      • material-counter0ms
    • 2. Recall Position0 tok · 7ms

      recall: 5 similar position(s) found (limit=5).

      • nex_search7ms
    • 3. Recall Opponent0 tok · 5ms

      No pattern found for chess-haiku-tm (tag=chess-haiku-tm) — mandatory run documented.

      • nex_entity_search5ms
    • 4. Research0 tok · 0ms · skipped

      research: opening_explorer + web_search both disabled — pure memory-only opening plan.

    • 5. Plan325 tok · 12891ms · claude-sonnet-4-6 · $0.0048

      Phase: opening. Respond to 1...d5 by maintaining central tension or advancing d4. Develop Nf3 to pressure d5 and prepare kingside castle. Knights before bishops — Nc3 or Nf3 next, then bishop development and castle by mo…

      • llm.plan12891ms · $0.0048
      full reasoning
      Phase: opening. Respond to 1...d5 by maintaining central tension or advancing d4. Develop Nf3 to pressure d5 and prepare kingside castle. Knights before bishops — Nc3 or Nf3 next, then bishop development and castle by move 6. Build a classical center with pawns on e4+d4, develop all minor pieces to active squares, castle kingside, and enter the middlegame with a space advantage and sound structure. Critical: Black has countered e4 with d5 — the Scandinavian or Center Counter setup. No immediate threats.; Central tension: exd5 captures but releases tension; d4 advances solidly; Nf3 develops and supports e4 without committing the d-pawn yet.; Memory heuristic 1 (central control): maintaining e4 or advancing d4 keeps maximum center presence — do not retreat or trade too early.; Memory heuristic 2 (knights before bishops): Nf3 is the natural developing move, pressures d5, prepares castling.; No king safety issues yet — full freedom, so prioritize development tempo over material..
    • 6. Candidates246 tok · 9617ms · claude-sonnet-4-6 · $0.0037

      Candidates: d4 (Builds classical center e4+d4, maintains maximum central control per heuristic 1, gives Black a problem to solve.) | Nf3 (Knights before bishops (heuristic 2): pressures d5, prepares kingside castle, deve…

      • chess.js.legal_moves0ms
      • llm.candidates9615ms · $0.0037
      full reasoning
      Candidates: d4 (Builds classical center e4+d4, maintains maximum central control per heuristic 1, gives Black a problem to solve.) | Nf3 (Knights before bishops (heuristic 2): pressures d5, prepares kingside castle, develops with tempo and no commitments.) | exd5 (Releases central tension but opens e-file; trade is sound if followed by Nf3 and rapid development.)
    • 7. Verify0 tok · 1ms

      Alle 3 Kandidaten legal. cloud_eval disabled (default).

      • chess.js.legal_recheck0ms
    • 8. Reflect191 tok · 9088ms · claude-sonnet-4-6 · $0.0028

      Final pick: exd5 — Captures with tempo, opens e-file for the rook, and forces Black to recapture — after Nf3 next we develop rapidly while Black's queen on d5 can be harassed with Nc3, gaining a tempo.. Rejected: d2d4, g…

      • llm.reflect9088ms · $0.0028
      full reasoning
      Final pick: exd5 — Captures with tempo, opens e-file for the rook, and forces Black to recapture — after Nf3 next we develop rapidly while Black's queen on d5 can be harassed with Nc3, gaining a tempo.. Rejected: d2d4, g1f3.
    • 9. Commit0 tok · 0ms

      Commit exd5 (e4d5).

  4. 4...Nf6Haiku12.342 tok · $0.0616 · 127453ms
    • 1. Observe0 tok · 0ms

      Halbzug 4, Schwarz am Zug. Phase: Eroeffnung. Weiss +1 Punkte. Legale Zuege: 28. Criticality: 0.30.

      • material-counter0ms
    • 2. Recall Position0 tok · 19ms

      recall: 5 similar position(s) found (limit=5).

      • nex_search19ms
    • 3. Recall Opponent0 tok · 5ms

      No pattern found for chess-sonnet-tm (tag=chess-sonnet-tm) — mandatory run documented.

      • nex_entity_search5ms
    • 4. Research0 tok · 0ms · skipped

      research: opening_explorer + web_search both disabled — pure memory-only opening plan.

    • 5. Plan3120 tok · 36755ms · claude-haiku-4-5 · $0.0156

      Phase: opening. Contest White's d5 pawn immediately (Qxd5 or Nf6). Accept tempo loss from queen retreat after Nc3 as Scandinavian standard exchange. Develop knights to f6 and c6 within 2 moves. Equalize material and spac…

      • llm.plan36755ms · $0.0156
      full reasoning
      Phase: opening. Contest White's d5 pawn immediately (Qxd5 or Nf6). Accept tempo loss from queen retreat after Nc3 as Scandinavian standard exchange. Develop knights to f6 and c6 within 2 moves. Equalize material and space by move 5. Transition to midgame with equal material, flexible pawn structure (c6/e6), safely centralized pieces, and kingside castled; neutralize White's space advantage. Critical: White's advanced d5 pawn claims center; must be contested or controlled immediately; Qxd5 followed by Nc3 forces queen retreat, but this tempo loss is standard and recoverable via rapid knight development; Undeveloped pieces (Nf6, Nc6, Bf5/Bg4) are weakness; knight development must happen within 2 moves or White's space becomes dangerous.
    • 6. Candidates1334 tok · 16406ms · claude-haiku-4-5 · $0.0066

      Candidates: Qxd5 (Immediately contest center; forces Nc3, standard Scandinavian exchange tempo sacrifice recoverable via rapid knight development) | Nf6 (Develop actively while attacking d5; maintains center pressure whi…

      • chess.js.legal_moves0ms
      • llm.candidates16403ms · $0.0066
      full reasoning
      Candidates: Qxd5 (Immediately contest center; forces Nc3, standard Scandinavian exchange tempo sacrifice recoverable via rapid knight development) | Nf6 (Develop actively while attacking d5; maintains center pressure while building piece coordination and kingside castling readiness) | e5 (Central pawn break from behind; claims space, opens routes for Nc6 and minor piece development with flexible structure)
    • 7. Verify0 tok · 1ms

      Alle 3 Kandidaten legal. cloud_eval disabled (default).

      • chess.js.legal_recheck0ms
    • 8. Reflect7888 tok · 74247ms · claude-haiku-4-5 · $0.0394

      Final pick: Nf6 — Develops actively with tempo, attacking d5 while enabling rapid follow-up piece development (c6, Nc6, Bf5). Keeps complexity and flexibility; more forcing than e5.. Rejected: d8d5, e7e5.

      • llm.reflect74247ms · $0.0394
    • 9. Commit0 tok · 0ms

      Commit Nf6 (g8f6).

  5. 5.Nf3Sonnet753 tok · $0.0112 · 33724ms
    • 1. Observe0 tok · 0ms

      Halbzug 5, Weiss am Zug. Phase: Eroeffnung. Weiss +1 Punkte. Legale Zuege: 30. Criticality: 0.30.

      • material-counter0ms
    • 2. Recall Position0 tok · 9ms

      recall: 5 similar position(s) found (limit=5).

      • nex_search9ms
    • 3. Recall Opponent0 tok · 7ms

      No pattern found for chess-haiku-tm (tag=chess-haiku-tm) — mandatory run documented.

      • nex_entity_search7ms
    • 4. Research0 tok · 0ms · skipped

      research: opening_explorer + web_search both disabled — pure memory-only opening plan.

    • 5. Plan326 tok · 15717ms · claude-sonnet-4-6 · $0.0049

      Phase: opening. Develop Nf3 to pressure d5 and prepare kingside castle. After Nf3, develop bishop to c4 or e2, castle kingside by move 6-7. Maintain pawn on d5 as space asset or recapture cleanly if Black challenges it. …

      • llm.plan15717ms · $0.0049
      full reasoning
      Phase: opening. Develop Nf3 to pressure d5 and prepare kingside castle. After Nf3, develop bishop to c4 or e2, castle kingside by move 6-7. Maintain pawn on d5 as space asset or recapture cleanly if Black challenges it. Build a classical space advantage with the d5 pawn as a wedge, develop all minor pieces actively (Nf3, Bc4 or Bf4, Nc3), castle kingside, and enter the middlegame with better piece coordination and central control. Critical: Black's Nf6 attacks nothing critical but is well-placed — do not allow it to reroute to e4 without challenge; Memory heuristic: knights before bishops — Nf3 is the priority move now (supports d5, eyes e5, enables castle); Memory heuristic: central control — d5 pawn gives space; Nc3 next reinforces center without overextending; No immediate threats from Black; this is a tempo-building moment for White; Queen must stay home — no early queen moves despite apparent activity on d-file.
    • 6. Candidates245 tok · 8913ms · claude-sonnet-4-6 · $0.0036

      Candidates: Nf3 (Knights before bishops heuristic: Nf3 develops naturally, supports d5 pawn, eyes e5, and enables kingside castle.) | Bc4 (Active bishop development targeting f7, maintaining central control pressure alon…

      • chess.js.legal_moves0ms
      • llm.candidates8911ms · $0.0036
      full reasoning
      Candidates: Nf3 (Knights before bishops heuristic: Nf3 develops naturally, supports d5 pawn, eyes e5, and enables kingside castle.) | Bc4 (Active bishop development targeting f7, maintaining central control pressure alongside d5 space asset.) | Nc3 (Central control heuristic: Nc3 reinforces the d5 pawn indirectly and builds piece coordination without overextending.)
    • 7. Verify0 tok · 0ms

      Alle 3 Kandidaten legal. cloud_eval disabled (default).

      • chess.js.legal_recheck0ms
    • 8. Reflect182 tok · 9056ms · claude-sonnet-4-6 · $0.0027

      Final pick: Nf3 — Knights before bishops heuristic demands Nf3 now: develops toward center, supports d5, eyes e5 square, and unlocks kingside castle. Bc4 and Nc3 both leave king uncastled longer.. Rejected: f1c4, b1c3.

      • llm.reflect9056ms · $0.0027
    • 9. Commit0 tok · 0ms

      Commit Nf3 (g1f3).

  6. 6...Qxd5Haiku11.955 tok · $0.0597 · 120810ms
    • 1. Observe0 tok · 0ms

      Halbzug 6, Schwarz am Zug. Phase: Eroeffnung. Weiss +1 Punkte. Legale Zuege: 31. Criticality: 0.30.

      • material-counter0ms
    • 2. Recall Position0 tok · 10ms

      recall: 5 similar position(s) found (limit=5).

      • nex_search10ms
    • 3. Recall Opponent0 tok · 5ms

      No pattern found for chess-sonnet-tm (tag=chess-sonnet-tm) — mandatory run documented.

      • nex_entity_search5ms
    • 4. Research0 tok · 0ms · skipped

      research: opening_explorer + web_search both disabled — pure memory-only opening plan.

    • 5. Plan3764 tok · 41743ms · claude-haiku-4-5 · $0.0188

      Phase: opening. Challenge d5 pawn via Qxd5; absorb queen retreat tempo (Nc3); develop Nc6 and Bf5/Bg5 rapidly. Equalize space/material by move 8. Reach middlegame with material parity, flexible pawn structure (c6/e6 avai…

      • llm.plan41743ms · $0.0188
      full reasoning
      Phase: opening. Challenge d5 pawn via Qxd5; absorb queen retreat tempo (Nc3); develop Nc6 and Bf5/Bg5 rapidly. Equalize space/material by move 8. Reach middlegame with material parity, flexible pawn structure (c6/e6 available), centralized minor pieces, and kingside castling complete. Critical: d5 pawn is White's space gain; unchallenged = permanent positional disadvantage; Severely underdeveloped: only Nf6 active; Nc6 and bishop must follow immediately next moves; Scandinavian tempo framework: Qxd5 Nc3 forces retreat, but Black develops with initiative; pattern is sound if executed precisely.
    • 6. Candidates5688 tok · 49259ms · claude-haiku-4-5 · $0.0284

      Candidates: Qxd5 (Seizes d5 pawn, forces Nc3, then develops rapidly with tempo. Core Scandinavian strategy.) | Nxd5 (Centralizes knight on d5 while equalizing material. Solid alternative to queen recapture.) | e5 (Pushes…

      • chess.js.legal_moves0ms
      • llm.candidates49257ms · $0.0284
      full reasoning
      Candidates: Qxd5 (Seizes d5 pawn, forces Nc3, then develops rapidly with tempo. Core Scandinavian strategy.) | Nxd5 (Centralizes knight on d5 while equalizing material. Solid alternative to queen recapture.) | e5 (Pushes pawn to gain central space and create immediate tactical tension. Aggressive option.)
    • 7. Verify0 tok · 1ms

      Alle 3 Kandidaten legal. cloud_eval disabled (default).

      • chess.js.legal_recheck0ms
    • 8. Reflect2503 tok · 29781ms · claude-haiku-4-5 · $0.0125

      Final pick: Qxd5 — Forces Nc3 immediately. Queen seizes d5 with tempo—attacks force White's knight out, then queen retreats to active square while developing. Textbook Scandinavian.. Rejected: f6d5, e7e5.

      • llm.reflect29781ms · $0.0125
    • 9. Commit0 tok · 0ms

      Commit Qxd5 (d8d5).

  7. 7.Nc3Sonnet756 tok · $0.0112 · 62416ms
    • 1. Observe0 tok · 0ms

      Halbzug 7, Weiss am Zug. Phase: Eroeffnung. Material gleich. Legale Zuege: 27. Criticality: 0.30.

      • material-counter0ms
    • 2. Recall Position0 tok · 12ms

      recall: 5 similar position(s) found (limit=5).

      • nex_search12ms
    • 3. Recall Opponent0 tok · 10ms

      No pattern found for chess-haiku-tm (tag=chess-haiku-tm) — mandatory run documented.

      • nex_entity_search10ms
    • 4. Research0 tok · 0ms · skipped

      research: opening_explorer + web_search both disabled — pure memory-only opening plan.

    • 5. Plan310 tok · 42359ms · claude-sonnet-4-6 · $0.0046

      Phase: opening. Develop Nc3 to challenge Black's queen on d5, then complete development with Bc4 targeting f7, and castle kingside by move 6. Force Black's queen to waste tempos while we gain piece activity. Exploit Blac…

      • llm.plan42359ms · $0.0046
      full reasoning
      Phase: opening. Develop Nc3 to challenge Black's queen on d5, then complete development with Bc4 targeting f7, and castle kingside by move 6. Force Black's queen to waste tempos while we gain piece activity. Exploit Black's prematurely active queen by developing with tempo, achieve full minor piece development and kingside castling before Black can consolidate, then press the slightly better-coordinated position into a middlegame edge. Critical: Black's queen on d5 is developed early — per memory heuristic 'queen late', this is a liability we must exploit by attacking it with Nc3 (tempo gain); Memory heuristic 'knights before bishops' confirms Nc3 is the correct next step before placing the bishop; Nf6 is well-placed but not immediately threatening — our Nf3 adequately monitors e4/d4; Own weakness: king still uncastled, e1-h4 diagonal potentially exposed — must castle within 2 moves; No immediate tactical threats from Black — positional development pressure is the dominant factor.
    • 6. Candidates249 tok · 10614ms · claude-sonnet-4-6 · $0.0037

      Candidates: Nc3 (Attacks Black's queen on d5 with tempo (knights before bishops heuristic), forces queen to waste another move while we develop.) | Bb5+ (Develops with check, disrupts Black's coordination; queen on d5 is…

      • chess.js.legal_moves0ms
      • llm.candidates10610ms · $0.0037
      full reasoning
      Candidates: Nc3 (Attacks Black's queen on d5 with tempo (knights before bishops heuristic), forces queen to waste another move while we develop.) | Bb5+ (Develops with check, disrupts Black's coordination; queen on d5 is a liability we exploit by forcing king-side activity.) | Bc4 (Classic development targeting f7 weakness; follows 'knights before bishops' already satisfied by Nf3, keeps king-castle path clear.)
    • 7. Verify0 tok · 1ms

      Alle 3 Kandidaten legal. cloud_eval disabled (default).

      • chess.js.legal_recheck0ms
    • 8. Reflect197 tok · 9401ms · claude-sonnet-4-6 · $0.0029

      Final pick: Nc3 — Attacks Black's queen on d5 with tempo, forcing it to move again. Per 'knights before bishops' heuristic, Nc3 before Bc4 is correct development order. Queen loses another move, we gain piece activity fr…

      • llm.reflect9401ms · $0.0029
      full reasoning
      Final pick: Nc3 — Attacks Black's queen on d5 with tempo, forcing it to move again. Per 'knights before bishops' heuristic, Nc3 before Bc4 is correct development order. Queen loses another move, we gain piece activity freely.. Rejected: f1b5, f1c4.
    • 9. Commit0 tok · 0ms

      Commit Nc3 (b1c3).

  8. 8...Nc6Haiku21.945 tok · $0.1096 · 182646ms
    • 1. Observe0 tok · 0ms

      Halbzug 8, Schwarz am Zug. Phase: Eroeffnung. Material gleich. Legale Zuege: 48. Criticality: 0.40.

      • material-counter0ms
    • 2. Recall Position0 tok · 7ms

      recall: 5 similar position(s) found (limit=5).

      • nex_search7ms
    • 3. Recall Opponent0 tok · 5ms

      No pattern found for chess-sonnet-tm (tag=chess-sonnet-tm) — mandatory run documented.

      • nex_entity_search5ms
    • 4. Research0 tok · 0ms · skipped

      research: opening_explorer + web_search both disabled — pure memory-only opening plan.

    • 5. Plan3450 tok · 34251ms · claude-haiku-4-5 · $0.0172

      Phase: opening. Develop Nc6 next (supports Queen, opens d-file). Follow with Bf5 or Bg4 to activate dark-square bishop. Queen d5 remains active but mobile—White's Nc3 will pressure it. Aim for pieces centralized and king…

      • llm.plan34251ms · $0.0172
      full reasoning
      Phase: opening. Develop Nc6 next (supports Queen, opens d-file). Follow with Bf5 or Bg4 to activate dark-square bishop. Queen d5 remains active but mobile—White's Nc3 will pressure it. Aim for pieces centralized and kingside castle-ready by move 6-7. Transition to middlegame with equal material and developed minor pieces. Space advantage for White (Nc3+Nf3 control e4/d4) persists; neutralize via Nc6 and flexible pawn structure (e6 or c6 available). Critical: Develop Nc6 immediately—delays invite d4 push from White; Queen d5 active but watch Nd5/Nxd5 tactics after Nc6 plays out; Missing knight on b8 and Bc8 development—cannot afford slow setup versus White's piece activity.
    • 6. Candidates6594 tok · 55736ms · claude-haiku-4-5 · $0.0329

      Candidates: Qxd2+ (Forcing check wins d2 pawn; after Qxd2 or King moves, material advantage secured) | Nc6 (Develops Nc6 supporting Queen, opens d-file, executes main development plan) | Bf5 (Activates Bf5, develops piec…

      • chess.js.legal_moves0ms
      • llm.candidates55731ms · $0.0329
      full reasoning
      Candidates: Qxd2+ (Forcing check wins d2 pawn; after Qxd2 or King moves, material advantage secured) | Nc6 (Develops Nc6 supporting Queen, opens d-file, executes main development plan) | Bf5 (Activates Bf5, develops piece, prepares castling kingside per plan)
    • 7. Verify0 tok · 2ms

      Alle 3 Kandidaten legal. cloud_eval disabled (default).

      • chess.js.legal_recheck0ms
    • 8. Reflect11901 tok · 92620ms · claude-haiku-4-5 · $0.0595

      Final pick: Nc6 — Develops the knight per plan, supports the queen on d5, opens the d-file, executes the stated opening strategy. Avoids tactical pitfalls while maintaining piece activity.. Rejected: d5d2, c8f5.

      • llm.reflect92620ms · $0.0595
    • 9. Commit0 tok · 0ms

      Commit Nc6 (b8c6).

  9. 9.Nxd5Sonnet752 tok · $0.0112 · 32894ms
    • 1. Observe0 tok · 0ms

      Halbzug 9, Weiss am Zug. Phase: Eroeffnung. Material gleich. Legale Zuege: 30. Criticality: 0.30.

      • material-counter0ms
    • 2. Recall Position0 tok · 10ms

      recall: 5 similar position(s) found (limit=5).

      • nex_search10ms
    • 3. Recall Opponent0 tok · 5ms

      No pattern found for chess-haiku-tm (tag=chess-haiku-tm) — mandatory run documented.

      • nex_entity_search5ms
    • 4. Research0 tok · 0ms · skipped

      research: opening_explorer + web_search both disabled — pure memory-only opening plan.

    • 5. Plan320 tok · 12891ms · claude-sonnet-4-6 · $0.0048

      Phase: opening. Develop Bc4 targeting f7 and threatening to castle kingside by move 6. Black's queen on d5 has already been challenged — now complete minor piece development with tempo before Black can consolidate. Bisho…

      • llm.plan12891ms · $0.0048
      full reasoning
      Phase: opening. Develop Bc4 targeting f7 and threatening to castle kingside by move 6. Black's queen on d5 has already been challenged — now complete minor piece development with tempo before Black can consolidate. Bishop to c4 pressures f7 and prepares immediate castling. Achieve full development and kingside castling by move 6, then convert slightly superior piece coordination into a stable middlegame edge against Black's prematurely active queen. Critical: Memory heuristic 'queen late' confirmed: Black's queen on d5 is a liability — every developing move we make with tempo forces it to retreat or creates tactical threats; Memory heuristic 'knights before bishops': both knights are now active (Nc3, Nf3), so Bc4 is the natural next step per development priority; Black's king is uncastled and f7 is a chronic weakness — Bc4 immediately targets this soft spot; No immediate tactical threats from Black — queen on d5 is passive, no discovered attacks or pins present; Own weakness: king still uncastled on e1, must castle this move or next.
    • 6. Candidates246 tok · 9457ms · claude-sonnet-4-6 · $0.0037

      Candidates: Bc4 (Targets f7 weakness directly; 'knights before bishops' heuristic fulfilled — both knights active, bishop development natural now.) | Nxd5 (Exploits Black's prematurely active queen ('queen late' heuristi…

      • chess.js.legal_moves0ms
      • llm.candidates9455ms · $0.0037
      full reasoning
      Candidates: Bc4 (Targets f7 weakness directly; 'knights before bishops' heuristic fulfilled — both knights active, bishop development natural now.) | Nxd5 (Exploits Black's prematurely active queen ('queen late' heuristic) — wins tempo forcing queen to recapture or retreat.) | Bb5 (Develops bishop with tempo, pins Nc6 and pressures Black's uncastled king coordination.)
    • 7. Verify0 tok · 1ms

      Alle 3 Kandidaten legal. cloud_eval disabled (default).

      • chess.js.legal_recheck0ms
    • 8. Reflect186 tok · 10513ms · claude-sonnet-4-6 · $0.0028

      Final pick: Nxd5 — Black's queen on d5 is a 'queen late' liability. Nxd5 wins a free tempo — queen must recapture or retreat, disrupting Black's coordination without any speculative sacrifice.. Rejected: f1c4, f1b5.

      • llm.reflect10513ms · $0.0028
    • 9. Commit0 tok · 0ms

      Commit Nxd5 (c3d5).

  10. 10...Bg4Haiku9.976 tok · $0.0498 · 103957ms
    • 1. Observe0 tok · 0ms

      Halbzug 10, Schwarz am Zug. Phase: Eroeffnung. Weiss +9 Punkte. Legale Zuege: 31. Criticality: 0.15.

      • material-counter0ms
    • 2. Recall Position0 tok · 17ms

      recall: 5 similar position(s) found (limit=5).

      • nex_search17ms
    • 3. Recall Opponent0 tok · 15ms

      No pattern found for chess-sonnet-tm (tag=chess-sonnet-tm) — mandatory run documented.

      • nex_entity_search15ms
    • 4. Research0 tok · 0ms · skipped

      research: opening_explorer + web_search both disabled — pure memory-only opening plan.

    • 5. Plan4264 tok · 43285ms · claude-haiku-4-5 · $0.0213

      Phase: opening. Black trails material (missing queen, +9). Activate Bf5/Bg4 immediately to create tactical friction. Castle kingside before White consolidates. Use Nc6+Nf6 as primary counterplay—one fork or forcing seque…

      • llm.plan43285ms · $0.0213
      full reasoning
      Phase: opening. Black trails material (missing queen, +9). Activate Bf5/Bg4 immediately to create tactical friction. Castle kingside before White consolidates. Use Nc6+Nf6 as primary counterplay—one fork or forcing sequence may offer practical chances. Objectively lost (9-point deficit). Fight for complications: pin Nf3 with Bg4, control key squares (e4, d4) via knight placement, trade pieces aggressively to simplify White's winning advantage. Critical: White Nd5 centralized but attackable—Nc6 can challenge it; Nf3 vulnerable to Bg4 pin + potential Ne4 fork in 2-3 moves; Both kings uncastled—Black must castle before midgame tactics explode; No queen means no attacking pawn breaks or mating nets—rely solely on knight/bishop tactics.
    • 6. Candidates1576 tok · 18774ms · claude-haiku-4-5 · $0.0078

      Candidates: Nxd5 (Remove White's strongest centralized knight. Simplifies position, reduces material advantage, tactical necessity.) | Bg4 (Pin Nf3 to queen, force tactical concessions. Create friction before White conso…

      • chess.js.legal_moves0ms
      • llm.candidates18768ms · $0.0078
      full reasoning
      Candidates: Nxd5 (Remove White's strongest centralized knight. Simplifies position, reduces material advantage, tactical necessity.) | Bg4 (Pin Nf3 to queen, force tactical concessions. Create friction before White consolidates dominance.) | Ne5 (Activate knight centrally, control key squares (d3, c4, f3), generate tactical counterplay. Threaten Nxf3.)
    • 7. Verify0 tok · 0ms

      Alle 3 Kandidaten legal. cloud_eval disabled (default).

      • chess.js.legal_recheck0ms
    • 8. Reflect4136 tok · 41846ms · claude-haiku-4-5 · $0.0206

      Final pick: Bg4 — Pin Nf3 to the queen immediately. Forces White's response before consolidation. Sets up Ne4 fork threat next move. Maximum tactical friction.. Rejected: f6d5, c6e5.

      • llm.reflect41846ms · $0.0206
    • 9. Commit0 tok · 0ms

      Commit Bg4 (c8g4).

  11. 11.Nxc7+Sonnet724 tok · $0.0108 · 35235ms
    • 1. Observe0 tok · 0ms

      Halbzug 11, Weiss am Zug. Phase: Eroeffnung. Weiss +9 Punkte. Legale Zuege: 33. Criticality: 0.15.

      • material-counter0ms
    • 2. Recall Position0 tok · 10ms

      recall: 5 similar position(s) found (limit=5).

      • nex_search10ms
    • 3. Recall Opponent0 tok · 7ms

      No pattern found for chess-haiku-tm (tag=chess-haiku-tm) — mandatory run documented.

      • nex_entity_search7ms
    • 4. Research0 tok · 0ms · skipped

      research: opening_explorer + web_search both disabled — pure memory-only opening plan.

    • 5. Plan281 tok · 11409ms · claude-sonnet-4-6 · $0.0042

      Phase: opening. Complete kingside development: bishop to c4 pressures f7, then castle kingside. Both knights are active (d5, f3) — add bishop pressure before Black consolidates. Force Black to react rather than develop. …

      • llm.plan11409ms · $0.0042
      full reasoning
      Phase: opening. Complete kingside development: bishop to c4 pressures f7, then castle kingside. Both knights are active (d5, f3) — add bishop pressure before Black consolidates. Force Black to react rather than develop. Convert superior piece coordination and the d5 knight outpost into a stable middlegame edge, targeting the weak f7 pawn and Black's undeveloped queenside. Critical: Memory heuristic 'knights before bishops' fulfilled — both knights active on d5/f3, now bishops must follow; Memory heuristic 'central control' confirmed — Nd5 dominates the center, Bc4 would reinforce f7-diagonal pressure; Black's bishop on g4 pins or pressures f3-knight — must account for this before castling; Black king uncastled on e8 — f7 weakness is the primary tactical target; Own king safety: must castle this move or next to avoid center exposure.
    • 6. Candidates252 tok · 13402ms · claude-sonnet-4-6 · $0.0037

      Candidates: Bc4 (Knights before bishops fulfilled — now bishop targets f7, reinforcing central control and d5 outpost pressure on uncastled Black king.) | Nxc7+ (Forks king and rook immediately, exploiting Black's uncast…

      • chess.js.legal_moves0ms
      • llm.candidates13400ms · $0.0037
      full reasoning
      Candidates: Bc4 (Knights before bishops fulfilled — now bishop targets f7, reinforcing central control and d5 outpost pressure on uncastled Black king.) | Nxc7+ (Forks king and rook immediately, exploiting Black's uncastled king — forced winning material gain with check.) | Nxf6+ (Eliminates Black's f6 defender with check, wrecking Black's kingside structure and maintaining central control via d5 domination.)
    • 7. Verify0 tok · 1ms

      Alle 3 Kandidaten legal. cloud_eval disabled (default).

      • chess.js.legal_recheck0ms
    • 8. Reflect191 tok · 10391ms · claude-sonnet-4-6 · $0.0028

      Final pick: Nxc7+ — Forced fork wins material immediately: Nxc7+ attacks king and Ra8 simultaneously. Black king on e8 is uncastled — this is a concrete tactical win, not a positional idea. Opponent cannot avoid losing t…

      • llm.reflect10391ms · $0.0028
      full reasoning
      Final pick: Nxc7+ — Forced fork wins material immediately: Nxc7+ attacks king and Ra8 simultaneously. Black king on e8 is uncastled — this is a concrete tactical win, not a positional idea. Opponent cannot avoid losing the rook.. Rejected: f1c4, d5f6.
    • 9. Commit0 tok · 0ms

      Commit Nxc7+ (d5c7).

  12. 12...Kd7Haiku8.430 tok · $0.0420 · 87557ms
    • 1. Observe0 tok · 0ms

      Halbzug 12, Schwarz am Zug. Phase: Eroeffnung. Weiss +10 Punkte. Legale Zuege: 2. Schach! Criticality: 0.60.

      • material-counter0ms
    • 2. Recall Position0 tok · 16ms

      recall: 5 similar position(s) found (limit=5).

      • nex_search16ms
    • 3. Recall Opponent0 tok · 12ms

      No pattern found for chess-sonnet-tm (tag=chess-sonnet-tm) — mandatory run documented.

      • nex_entity_search12ms
    • 4. Research0 tok · 0ms · skipped

      research: opening_explorer + web_search both disabled — pure memory-only opening plan.

    • 5. Plan5206 tok · 43817ms · claude-haiku-4-5 · $0.0260

      Phase: opening. Deliver Nd4+ check to force White's king move (Kd1/Kf1/Ke2), then activate Ne5 or Nf6+ tactics around White's exposed king. Trade pieces aggressively to simplify Black's material deficit through tactical …

      • llm.plan43817ms · $0.0260
      full reasoning
      Phase: opening. Deliver Nd4+ check to force White's king move (Kd1/Kf1/Ke2), then activate Ne5 or Nf6+ tactics around White's exposed king. Trade pieces aggressively to simplify Black's material deficit through tactical friction. Exploit uncastled king with Nd4+ check and forcing follow-ups; centralize knights via e5/d4; trade material to reduce White's winning advantage. Critical: White Nc7 is deep but can be attacked; Nf3 pinned by Bg4; White king e1 vulnerable to knight forks from d4/e5 squares; Black Ra8 attacked; Black must play forcing moves only (objective loss needs maximum complications).
    • 6. Candidates1853 tok · 25777ms · claude-haiku-4-5 · $0.0092

      Candidates: Kd7 (Centralizes king, enables Ne5+ tactics and aggressive knight placement) | Kd8 (Passive retreat, secures king but limits piece activity and tactics)

      • chess.js.legal_moves0ms
      • llm.candidates25777ms · $0.0092
    • 7. Verify0 tok · 1ms

      Alle 2 Kandidaten legal. cloud_eval disabled (default).

      • chess.js.legal_recheck0ms
    • 8. Reflect1371 tok · 17928ms · claude-haiku-4-5 · $0.0068

      Final pick: Kd7 — Centralizes king to support Ne5 and Nd4+ tactical motifs. Prepares forcing knight checks on d4 while keeping king active. Passive Kd8 surrenders initiative Black desperately needs in material deficit.. …

      • llm.reflect17928ms · $0.0068
      full reasoning
      Final pick: Kd7 — Centralizes king to support Ne5 and Nd4+ tactical motifs. Prepares forcing knight checks on d4 while keeping king active. Passive Kd8 surrenders initiative Black desperately needs in material deficit.. Rejected: e8d8.
    • 9. Commit0 tok · 0ms

      Commit Kd7 (e8d7).

  13. 13.Bc4Sonnet791 tok · $0.0118 · 36899ms
    • 1. Observe0 tok · 0ms

      Halbzug 13, Weiss am Zug. Phase: Eroeffnung. Weiss +10 Punkte. Legale Zuege: 31. Criticality: 0.15.

      • material-counter0ms
    • 2. Recall Position0 tok · 15ms

      recall: 5 similar position(s) found (limit=5).

      • nex_search15ms
    • 3. Recall Opponent0 tok · 8ms

      No pattern found for chess-haiku-tm (tag=chess-haiku-tm) — mandatory run documented.

      • nex_entity_search8ms
    • 4. Research0 tok · 0ms · skipped

      research: opening_explorer + web_search both disabled — pure memory-only opening plan.

    • 5. Plan348 tok · 14974ms · claude-sonnet-4-6 · $0.0052

      Phase: opening. Deploy Bc4 targeting f7, then castle kingside. Nd5 and Nf3 are both active — bishop development completes the minor piece mobilization. After castling, pressure f7 with coordinated Bc4+Nd5+Nf3 triangle fo…

      • llm.plan14974ms · $0.0052
      full reasoning
      Phase: opening. Deploy Bc4 targeting f7, then castle kingside. Nd5 and Nf3 are both active — bishop development completes the minor piece mobilization. After castling, pressure f7 with coordinated Bc4+Nd5+Nf3 triangle forces Black to defend passively. Convert the dominant Nd5 outpost and f7 pressure into a lasting middlegame initiative while castling to safety before Black's bishop pair on g4/g7 becomes dangerous. Critical: Memory heuristic 'knights before bishops' fulfilled — Nd5+Nf3 active, now Bc4 MUST follow to complete development per the heuristic sequence; Memory heuristic 'central control' confirmed — Nd5 dominates, Bc4 reinforces the f7-diagonal and the central grip; Black's Bg4 pins or threatens Nf3 — must assess if bishop development or immediate h3 to challenge the pin is more urgent; Black king on d7 is exposed — f7 pawn is a structural weakness under Bc4 pressure; Own king still uncastled on e1 — castling kingside is urgent before position opens further.
    • 6. Candidates257 tok · 12867ms · claude-sonnet-4-6 · $0.0038

      Candidates: Bc4 (Completes minor piece development per 'knights before bishops' heuristic; targets exposed f7 pawn near Black's uncastled king on d7.) | Nd5 (Dominant central outpost per 'central control' heuristic; knig…

      • chess.js.legal_moves0ms
      • llm.candidates12866ms · $0.0038
      full reasoning
      Candidates: Bc4 (Completes minor piece development per 'knights before bishops' heuristic; targets exposed f7 pawn near Black's uncastled king on d7.) | Nd5 (Dominant central outpost per 'central control' heuristic; knight on d5 forks multiple targets and pressures exposed Black king.) | h3 (Challenges Black's Bg4 pin on Nf3 before castling; secures knight activity without worsening own king safety.)
    • 7. Verify0 tok · 1ms

      Alle 3 Kandidaten legal. cloud_eval disabled (default).

      • chess.js.legal_recheck0ms
    • 8. Reflect186 tok · 9012ms · claude-sonnet-4-6 · $0.0028

      Final pick: Bc4 — Completes minor piece development per 'knights before bishops' heuristic, aims Bc4 at f7 near Black's exposed king on d7. Creates immediate concrete threats forcing passive defense before castling.. Rej…

      • llm.reflect9012ms · $0.0028
      full reasoning
      Final pick: Bc4 — Completes minor piece development per 'knights before bishops' heuristic, aims Bc4 at f7 near Black's exposed king on d7. Creates immediate concrete threats forcing passive defense before castling.. Rejected: c7d5, h2h3.
    • 9. Commit0 tok · 0ms

      Commit Bc4 (f1c4).

  14. 14...Kxc7Haiku20.066 tok · $0.1002 · 177595ms
    • 1. Observe0 tok · 0ms

      Halbzug 14, Schwarz am Zug. Phase: Eroeffnung. Weiss +10 Punkte. Legale Zuege: 35. Criticality: 0.25.

      • material-counter0ms
    • 2. Recall Position0 tok · 10ms

      recall: 5 similar position(s) found (limit=5).

      • nex_search10ms
    • 3. Recall Opponent0 tok · 8ms

      No pattern found for chess-sonnet-tm (tag=chess-sonnet-tm) — mandatory run documented.

      • nex_entity_search8ms
    • 4. Research0 tok · 0ms · skipped

      research: opening_explorer + web_search both disabled — pure memory-only opening plan.

    • 5. Plan1588 tok · 19838ms · claude-haiku-4-5 · $0.0079

      Phase: opening. Force White's king to move with Nd4+ check, then trade pieces aggressively to simplify material advantage. Create tactical friction around exposed kings. Reduce White's +10 material advantage through forc…

      • llm.plan19838ms · $0.0079
      full reasoning
      Phase: opening. Force White's king to move with Nd4+ check, then trade pieces aggressively to simplify material advantage. Create tactical friction around exposed kings. Reduce White's +10 material advantage through forcing moves and piece exchanges; centralize Black's knights via e5/d4; move king to safety after forcing White's king move. Critical: White Nc7 attacks Ra8 (loose piece, but Nd4+ takes priority as forcing check); White king on e1 vulnerable to Nd4+ fork; forces Kd1, Kf1, or Ke2; Black king on d7 exposed; must relocate to safety after forcing White's king displacement; Nf3 pinned by Bg4; Nd4+ unpins while delivering check, creates multiple tactical threats.
    • 6. Candidates6198 tok · 55321ms · claude-haiku-4-5 · $0.0310

      Candidates: Kxc7 (Captures undefended knight on c7, gains material to close 10-point deficit.) | Bxf3 (Wins pinned knight on f3, forces weakening of White's kingside structure.) | Nd4 (Centralizes knight, creates multipl…

      • chess.js.legal_moves0ms
      • llm.candidates55319ms · $0.0310
      full reasoning
      Candidates: Kxc7 (Captures undefended knight on c7, gains material to close 10-point deficit.) | Bxf3 (Wins pinned knight on f3, forces weakening of White's kingside structure.) | Nd4 (Centralizes knight, creates multiple threats to e2 and f3, forces White response.)
    • 7. Verify0 tok · 0ms

      Alle 3 Kandidaten legal. cloud_eval disabled (default).

      • chess.js.legal_recheck0ms
    • 8. Reflect12280 tok · 102403ms · claude-haiku-4-5 · $0.0614

      Final pick: Kxc7 — Captures undefended Nc7, gaining +3 material and removing threat to Ra8. Concrete, safe improvement when down a queen.. Rejected: g4f3, c6d4.

      • llm.reflect102403ms · $0.0614
    • 9. Commit0 tok · 0ms

      Commit Kxc7 (d7c7).

  15. 15.Bxf7Sonnet759 tok · $0.0113 · 34294ms
    • 1. Observe0 tok · 0ms

      Halbzug 15, Weiss am Zug. Phase: Eroeffnung. Weiss +7 Punkte. Legale Zuege: 31. Criticality: 0.15.

      • material-counter0ms
    • 2. Recall Position0 tok · 10ms

      recall: 5 similar position(s) found (limit=5).

      • nex_search10ms
    • 3. Recall Opponent0 tok · 7ms

      No pattern found for chess-haiku-tm (tag=chess-haiku-tm) — mandatory run documented.

      • nex_entity_search7ms
    • 4. Research0 tok · 0ms · skipped

      research: opening_explorer + web_search both disabled — pure memory-only opening plan.

    • 5. Plan276 tok · 13871ms · claude-sonnet-4-6 · $0.0041

      Phase: opening. Castle kingside immediately to secure the king, then activate the bishop to c4 targeting f7. The Bc4+Nf3 battery creates lasting f7 pressure. Black's king on c7 is exposed — punish it before Black consoli…

      • llm.plan13871ms · $0.0041
      full reasoning
      Phase: opening. Castle kingside immediately to secure the king, then activate the bishop to c4 targeting f7. The Bc4+Nf3 battery creates lasting f7 pressure. Black's king on c7 is exposed — punish it before Black consolidates with ...e6 or ...d6. Convert White's 7-point material/space lead and Black's misplaced king into a decisive middlegame advantage by castling first (memory: king safety above all), then building a coordinated f7-attack triangle with Bc4+Nf3. Critical: Black's Bg4 pins nothing yet but will become dangerous if White delays castling — the 'central control' heuristic demands we stabilize before advancing; Black king on c7 is a long-term target: keep queens on board; Bg4 on h5-e8 diagonal could become active — castle NOW per 'knights before bishops' completion sequence before Black organizes counterplay.
    • 6. Candidates252 tok · 9875ms · claude-sonnet-4-6 · $0.0037

      Candidates: O-O (King safety first — castles immediately, activates rook, per core identity heuristic: king safety before initiative.) | Bxf7 (Trades bishop for f7-pawn, forks king and rook, exploits Black's exposed king…

      • chess.js.legal_moves0ms
      • llm.candidates9872ms · $0.0037
      full reasoning
      Candidates: O-O (King safety first — castles immediately, activates rook, per core identity heuristic: king safety before initiative.) | Bxf7 (Trades bishop for f7-pawn, forks king and rook, exploits Black's exposed king on c7 with forcing material gain.) | Ne5 (Centralized knight targets c6 and f7 simultaneously; improves worst piece per Sonnet's 'improve worst piece' heuristic.)
    • 7. Verify0 tok · 1ms

      Alle 3 Kandidaten legal. cloud_eval disabled (default).

      • chess.js.legal_recheck0ms
    • 8. Reflect231 tok · 10517ms · claude-sonnet-4-6 · $0.0034

      Final pick: Bxf7 — Bxf7+ forks king and rook immediately. Black king on c7 has no safe square — Ke6 runs into Ng5+, Kd6 into Qd5#. Material gain is forced: rook on h8 falls next. King safety heuristic satisfied by elimin…

      • llm.reflect10517ms · $0.0034
      full reasoning
      Final pick: Bxf7 — Bxf7+ forks king and rook immediately. Black king on c7 has no safe square — Ke6 runs into Ng5+, Kd6 into Qd5#. Material gain is forced: rook on h8 falls next. King safety heuristic satisfied by eliminating Black's counterplay first.. Rejected: e1g1, f3e5.
    • 9. Commit0 tok · 0ms

      Commit Bxf7 (c4f7).

  16. 16...Nd4Haiku12.803 tok · $0.0639 · 120358ms
    • 1. Observe0 tok · 1ms

      Halbzug 16, Schwarz am Zug. Phase: Mittelspiel. Weiss +8 Punkte. Legale Zuege: 40. Criticality: 0.10.

      • material-counter0ms
    • 2. Recall Position0 tok · 11ms

      recall: 5 similar position(s) found (limit=5).

      • nex_search11ms
    • 3. Recall Opponent0 tok · 6ms

      No pattern found for chess-sonnet-tm (tag=chess-sonnet-tm) — mandatory run documented.

      • nex_entity_search6ms
    • 4. Research0 tok · 0ms · skipped

      middlegame/endgame — research not relevant when both tools off.

    • 5. Plan5874 tok · 53249ms · claude-haiku-4-5 · $0.0293

      Phase: middlegame. Centralize knights via Nd4 or Ne5 to attack pinned Nf3 and support Bg4 pressure. Create tactical threats against exposed Ke1. Exchange pieces to reduce material deficit. Exploit White's exposed king an…

      • llm.plan53249ms · $0.0293
      full reasoning
      Phase: middlegame. Centralize knights via Nd4 or Ne5 to attack pinned Nf3 and support Bg4 pressure. Create tactical threats against exposed Ke1. Exchange pieces to reduce material deficit. Exploit White's exposed king and incomplete development to force simplification and reach a drawable endgame despite material disadvantage. Critical: White's Bf7 dominates the 7th rank; neutralize through tactics or favorable exchange; Black's Bg4 pin on Nf3 is the key restraint on White's development; maintain pressure; White's Ke1 exposed to knight tactics (Nd4, Ne5 ideas); must be exploited concretely; Black's Kc7 is somewhat exposed; improve safety after forcing White's king response; Material deficit (-7) demands active, concrete play; passive positions are lost.
    • 6. Candidates1788 tok · 19283ms · claude-haiku-4-5 · $0.0089

      Candidates: Bxf3 (Removes pinned knight, simplifies material, opens h-file toward White's exposed Ke1, creates immediate tactical pressure) | Ne5 (Centralizes knight, pressures White's position, supports attack against e…

      • chess.js.legal_moves0ms
      • llm.candidates19280ms · $0.0089
      full reasoning
      Candidates: Bxf3 (Removes pinned knight, simplifies material, opens h-file toward White's exposed Ke1, creates immediate tactical pressure) | Ne5 (Centralizes knight, pressures White's position, supports attack against exposed king, maintains Bg4 pin strategy) | Nd4 (Centralizes knight to strong square, attacks multiple points, threatens fork ideas against Ke1, coordinates pieces)
    • 7. Verify0 tok · 1ms

      Alle 3 Kandidaten legal. cloud_eval disabled (default).

      • chess.js.legal_recheck0ms
    • 8. Reflect5141 tok · 47780ms · claude-haiku-4-5 · $0.0257

      Final pick: Nd4 — Centralizes knight to strong square, threatens Nxf3+ (check), forcing White to respond immediately. Exploits exposed Ke1 concretely and maintains Black's tactical initiative.. Rejected: g4f3, c6e5.

      • llm.reflect47780ms · $0.0257
    • 9. Commit0 tok · 0ms

      Commit Nd4 (c6d4).

  17. 17.O-OSonnet737 tok · $0.0109 · 35441ms
    • 1. Observe0 tok · 0ms

      Halbzug 17, Weiss am Zug. Phase: Mittelspiel. Weiss +8 Punkte. Legale Zuege: 29. Criticality: 0.00.

      • material-counter0ms
    • 2. Recall Position0 tok · 13ms

      recall: 5 similar position(s) found (limit=5).

      • nex_search13ms
    • 3. Recall Opponent0 tok · 7ms

      No pattern found for chess-haiku-tm (tag=chess-haiku-tm) — mandatory run documented.

      • nex_entity_search7ms
    • 4. Research0 tok · 0ms · skipped

      middlegame/endgame — research not relevant when both tools off.

    • 5. Plan291 tok · 16424ms · claude-sonnet-4-6 · $0.0043

      Phase: middlegame. Castle kingside immediately to resolve king safety, then exploit Black's exposed king on c7 with Bc4 targeting f7. The open-file heuristic (memory: MIDDLE open file rooks) demands rook activation after…

      • llm.plan16424ms · $0.0043
      full reasoning
      Phase: middlegame. Castle kingside immediately to resolve king safety, then exploit Black's exposed king on c7 with Bc4 targeting f7. The open-file heuristic (memory: MIDDLE open file rooks) demands rook activation after castling — Ra1 and Rh1 will become lethal on open files once Black's position cracks. Maintain piece coordination: Nf3 + Bc4 + Rooks converging on Black's kingside void. Convert the 8-point material lead and Black's chronically exposed king (c7) into a decisive attack by castling now, activating Bc4, and using open files for the rooks per the open-file heuristic — Black has no fortress to hide in. Critical: Black's Nd4 is deeply centralized and threatens disruption — must not ignore; Black's Bg4 will become a pin threat if White's king lingers uncastled; Black's king on c7 is the primary target — every move must increase pressure on it.
    • 6. Candidates238 tok · 9965ms · claude-sonnet-4-6 · $0.0035

      Candidates: O-O (King safety first: resolves uncastled king immediately, activates Rh1 on open file per memory heuristic.) | Bc4 (Targets f7 and Black's exposed king on c7; coordinates with Nf3 for converging attack.) | …

      • chess.js.legal_moves0ms
      • llm.candidates9962ms · $0.0035
      full reasoning
      Candidates: O-O (King safety first: resolves uncastled king immediately, activates Rh1 on open file per memory heuristic.) | Bc4 (Targets f7 and Black's exposed king on c7; coordinates with Nf3 for converging attack.) | Nxd4 (Eliminates centralized Nd4 threat before it disrupts; gains material and opens center.)
    • 7. Verify0 tok · 0ms

      Alle 3 Kandidaten legal. cloud_eval disabled (default).

      • chess.js.legal_recheck0ms
    • 8. Reflect208 tok · 9020ms · claude-sonnet-4-6 · $0.0031

      Final pick: O-O — King safety is non-negotiable before attacking. Castling activates Rh1 on the open h-file per the open-file rooks heuristic, and removes the pin threat from Bg4. Only then can Bc4 and rook pressure be u…

      • llm.reflect9020ms · $0.0031
      full reasoning
      Final pick: O-O — King safety is non-negotiable before attacking. Castling activates Rh1 on the open h-file per the open-file rooks heuristic, and removes the pin threat from Bg4. Only then can Bc4 and rook pressure be unleashed safely.. Rejected: f7c4, f3d4.
    • 9. Commit0 tok · 0ms

      Commit O-O (e1g1).

  18. 18...Nxf3+Haiku11.527 tok · $0.0575 · 112079ms
    • 1. Observe0 tok · 0ms

      Halbzug 18, Schwarz am Zug. Phase: Mittelspiel. Weiss +8 Punkte. Legale Zuege: 43. Criticality: 0.10.

      • material-counter0ms
    • 2. Recall Position0 tok · 7ms

      recall: 5 similar position(s) found (limit=5).

      • nex_search7ms
    • 3. Recall Opponent0 tok · 7ms

      No pattern found for chess-sonnet-tm (tag=chess-sonnet-tm) — mandatory run documented.

      • nex_entity_search7ms
    • 4. Research0 tok · 0ms · skipped

      middlegame/endgame — research not relevant when both tools off.

    • 5. Plan4095 tok · 41312ms · claude-haiku-4-5 · $0.0204

      Phase: middlegame. Centralize knights to create tactical threats on White's semi-exposed king (Ne2+, Nf4 ideas). Maintain Bg4 pin on Nf3. Exchange pieces favorably to reduce material deficit. Force White's pieces into re…

      • llm.plan41312ms · $0.0204
      full reasoning
      Phase: middlegame. Centralize knights to create tactical threats on White's semi-exposed king (Ne2+, Nf4 ideas). Maintain Bg4 pin on Nf3. Exchange pieces favorably to reduce material deficit. Force White's pieces into reactive positions while keeping Black's piece coordination intact. Exploit piece activity and concrete tactics to achieve favorable simplifications, reaching an endgame where activity compensates for the material deficit. Critical: Bf7 dominates 7th rank and restricts e7—must be neutralized or traded favorably. Bg4 pin on Nf3 is key restraint preventing White's development. Knight tactics (Ne2+ and Nf4) exploit semi-exposed Kg1. White's Q and R coordination incomplete; Black must seize tempo..
    • 6. Candidates2876 tok · 27872ms · claude-haiku-4-5 · $0.0143

      Candidates: Nxf3+ (Captures pinned knight with check, forcing king move and gaining tempo while simplifying) | Nxc2 (Centralizes knight to aggressive square, captures pawn and threatens multiple pieces tactically) | Bxf3…

      • chess.js.legal_moves0ms
      • llm.candidates27867ms · $0.0143
      full reasoning
      Candidates: Nxf3+ (Captures pinned knight with check, forcing king move and gaining tempo while simplifying) | Nxc2 (Centralizes knight to aggressive square, captures pawn and threatens multiple pieces tactically) | Bxf3 (Captures weakened knight, maintains pressure and piece coordination while simplifying material favorably)
    • 7. Verify0 tok · 1ms

      Alle 3 Kandidaten legal. cloud_eval disabled (default).

      • chess.js.legal_recheck0ms
    • 8. Reflect4556 tok · 42870ms · claude-haiku-4-5 · $0.0227

      Final pick: Nxf3+ — Captures pinned knight with check, forcing king to h1 or f2, gaining tempo while knight remains active from f3. Simplifies favorably.. Rejected: d4c2, g4f3.

      • llm.reflect42870ms · $0.0227
    • 9. Commit0 tok · 0ms

      Commit Nxf3+ (d4f3).

  19. 19.Qxf3Sonnet787 tok · $0.0117 · 34420ms
    • 1. Observe0 tok · 0ms

      Halbzug 19, Weiss am Zug. Phase: Mittelspiel. Weiss +5 Punkte. Legale Zuege: 3. Schach! Criticality: 0.45.

      • material-counter0ms
    • 2. Recall Position0 tok · 14ms

      recall: 5 similar position(s) found (limit=5).

      • nex_search14ms
    • 3. Recall Opponent0 tok · 7ms

      No pattern found for chess-haiku-tm (tag=chess-haiku-tm) — mandatory run documented.

      • nex_entity_search7ms
    • 4. Research0 tok · 0ms · skipped

      middlegame/endgame — research not relevant when both tools off.

    • 5. Plan332 tok · 14549ms · claude-sonnet-4-6 · $0.0049

      Phase: middlegame. With only 3 legal moves available and White +5 material, identify the forcing continuation that exploits Black's king on c7. The Bf7 bishop is already deep in Black's camp — maximize this tactical pres…

      • llm.plan14549ms · $0.0049
      full reasoning
      Phase: middlegame. With only 3 legal moves available and White +5 material, identify the forcing continuation that exploits Black's king on c7. The Bf7 bishop is already deep in Black's camp — maximize this tactical pressure while neutralizing Black's Ng3/Ng4 threats against White's king. Convert the massive material advantage by eliminating Black's active knights (Nf3/Ng4 are threats) and driving through with the open-file rooks per the open-file heuristic — White's Rooks on a1/f1 must reach open files to deliver the decisive blow against Black's exposed king. Critical: Black has Nf3 and Ng4 — both knights threaten White king vicinity, Nf3 may already give check or fork threats; Only 3 legal moves means White is in check or near-zugzwang — the Observe-Notes confirm 'Schach!' so White IS in check from Nf3; Memory heuristic MIDDLE open file rooks: after resolving check, activate Rf1 on open f-file immediately — Bf7 anchor + Rf1 = mating pressure on f7/e8 corridor.
    • 6. Candidates238 tok · 10431ms · claude-sonnet-4-6 · $0.0035

      Candidates: Qxf3 (Captures checking knight with tempo, centralizes queen, open f-file activates Rf1 per open-file heuristic.) | gxf3 (Removes checking knight, opens g-file but weakens king safety — pawn structure cost no…

      • chess.js.legal_moves0ms
      • llm.candidates10431ms · $0.0035
      full reasoning
      Candidates: Qxf3 (Captures checking knight with tempo, centralizes queen, open f-file activates Rf1 per open-file heuristic.) | gxf3 (Removes checking knight, opens g-file but weakens king safety — pawn structure cost noted.) | Kh1 (King safety first principle: sidesteps check, preserves material, but leaves Nf3 active.)
    • 7. Verify0 tok · 0ms

      Alle 3 Kandidaten legal. cloud_eval disabled (default).

      • chess.js.legal_recheck0ms
    • 8. Reflect217 tok · 9408ms · claude-sonnet-4-6 · $0.0032

      Final pick: Qxf3 — Captures the checking Nf3 with the queen, eliminating both check and the active knight. Centralizes the queen and opens the f-file for Rf1, activating the rook per open-file heuristic with Bf7 already …

      • llm.reflect9408ms · $0.0032
      full reasoning
      Final pick: Qxf3 — Captures the checking Nf3 with the queen, eliminating both check and the active knight. Centralizes the queen and opens the f-file for Rf1, activating the rook per open-file heuristic with Bf7 already anchored deep.. Rejected: g2f3, g1h1.
    • 9. Commit0 tok · 0ms

      Commit Qxf3 (d1f3).

  20. 20...Bxf3Haiku7.269 tok · $0.0362 · 86892ms
    • 1. Observe0 tok · 1ms

      Halbzug 20, Schwarz am Zug. Phase: Mittelspiel. Weiss +8 Punkte. Legale Zuege: 34. Criticality: 0.00.

      • material-counter0ms
    • 2. Recall Position0 tok · 17ms

      recall: 5 similar position(s) found (limit=5).

      • nex_search17ms
    • 3. Recall Opponent0 tok · 8ms

      No pattern found for chess-sonnet-tm (tag=chess-sonnet-tm) — mandatory run documented.

      • nex_entity_search8ms
    • 4. Research0 tok · 0ms · skipped

      middlegame/endgame — research not relevant when both tools off.

    • 5. Plan1202 tok · 18794ms · claude-haiku-4-5 · $0.0060

      Phase: middlegame. Centralize knight to e2 with check/fork motif, forcing White's king to move or White to make concessions. Maintain Bg4 pin on Nf3 to prevent coordination of White's attack. Exchange White's dangerous B…

      • llm.plan18794ms · $0.0060
      full reasoning
      Phase: middlegame. Centralize knight to e2 with check/fork motif, forcing White's king to move or White to make concessions. Maintain Bg4 pin on Nf3 to prevent coordination of White's attack. Exchange White's dangerous Bf7 or Qf3 when possible. Drive toward simplification where Black's piece activity holds despite material deficit. Achieve favorable endgame through concrete tactics and piece exchanges, where Black's centralized knights and active bishops compensate for material shortage. Critical: Opponent threat: White's Bf7 controls 7th rank and e8-escape; Qf3 supports attack on Kc7; Own weakness: Material deficit (-8) requires immediate tactical justification; Kc7 semi-exposed; Tactical threat: Ne2+ fork/check sequence; discovered attack leverage from Bg4 on e2-e6 square.
    • 6. Candidates3750 tok · 43267ms · claude-haiku-4-5 · $0.0187

      Candidates: Bxf3 (Captures White's dangerous queen, removes main attacking threat on Kc7, forces simplification.) | Ne4 (Centralizes knight toward e2 check/fork motif, improves coordination, threatens multiple squares.) …

      • chess.js.legal_moves0ms
      • llm.candidates43265ms · $0.0187
      full reasoning
      Candidates: Bxf3 (Captures White's dangerous queen, removes main attacking threat on Kc7, forces simplification.) | Ne4 (Centralizes knight toward e2 check/fork motif, improves coordination, threatens multiple squares.) | e5 (Expands center presence, supports piece activity, drives toward simplification where activity compensates material deficit.)
    • 7. Verify0 tok · 1ms

      Alle 3 Kandidaten legal. cloud_eval disabled (default).

      • chess.js.legal_recheck0ms
    • 8. Reflect2317 tok · 24784ms · claude-haiku-4-5 · $0.0115

      Final pick: Bxf3 — Captures White's Queen immediately, transforming material deficit from -8 to -2, eliminating the primary attacking threat against Kc7, forcing simplification where activity compensates.. Rejected: f6e4…

      • llm.reflect24784ms · $0.0115
      full reasoning
      Final pick: Bxf3 — Captures White's Queen immediately, transforming material deficit from -8 to -2, eliminating the primary attacking threat against Kc7, forcing simplification where activity compensates.. Rejected: f6e4, e7e5.
    • 9. Commit0 tok · 0ms

      Commit Bxf3 (g4f3).

  21. 21.gxf3Sonnet830 tok · $0.0123 · 34842ms
    • 1. Observe0 tok · 0ms

      Halbzug 21, Weiss am Zug. Phase: Mittelspiel. Schwarz +1 Punkte. Legale Zuege: 25. Criticality: 0.15.

      • material-counter0ms
    • 2. Recall Position0 tok · 16ms

      recall: 5 similar position(s) found (limit=5).

      • nex_search16ms
    • 3. Recall Opponent0 tok · 8ms

      No pattern found for chess-haiku-tm (tag=chess-haiku-tm) — mandatory run documented.

      • nex_entity_search8ms
    • 4. Research0 tok · 0ms · skipped

      middlegame/endgame — research not relevant when both tools off.

    • 5. Plan376 tok · 14855ms · claude-sonnet-4-6 · $0.0056

      Phase: middlegame. Convert +5 material by activating rooks on open files while the Bf7 pins Black's king to c7 — push for a forcing continuation that eliminates Black's active knight on f6 and threatens decisive back-ran…

      • llm.plan14855ms · $0.0056
      full reasoning
      Phase: middlegame. Convert +5 material by activating rooks on open files while the Bf7 pins Black's king to c7 — push for a forcing continuation that eliminates Black's active knight on f6 and threatens decisive back-rank pressure with Ra1 and Rf1 entering open files. White's overwhelming material advantage should be converted by mobilizing the rooks onto open files (open-file rooks heuristic) pointing at Black's exposed king on c7, while the Bf7 bishop anchors deep in Black's camp as a permanent irritant — simplify by trading off Black's only active defenders. Critical: Black's Nf6 is the sole active defensive piece — eliminating or blocking it removes Black's last counterplay; Black's king on c7 is exposed with no safe haven — rooks must reach open c- or d-file to deliver decisive threats; White's own king on g1 is relatively safe but must not allow Bf3 or Ng4 infiltration — king safety check first before committing rooks forward; Doubled/isolated pawn heuristic irrelevant here — no structural weakness to exploit; pure king hunt via piece activity; Open-file rooks heuristic is primary: Ra1 and Rf1 must find open lines toward c7 or the kingside to translate material into checkmate threats.
    • 6. Candidates267 tok · 10881ms · claude-sonnet-4-6 · $0.0040

      Candidates: gxf3 (Eliminates Black's active Bf3, opens g-file for rook; king safety check — removes infiltrating bishop threatening g2.) | Bd5 (Centralizes bishop, attacks Nf6 (Black's sole defender) and eyes a8-rook; op…

      • chess.js.legal_moves0ms
      • llm.candidates10880ms · $0.0040
      full reasoning
      Candidates: gxf3 (Eliminates Black's active Bf3, opens g-file for rook; king safety check — removes infiltrating bishop threatening g2.) | Bd5 (Centralizes bishop, attacks Nf6 (Black's sole defender) and eyes a8-rook; open-file rooks heuristic: clears f7 for rook.) | Re1 (Activates rook on open e-file toward exposed king on c7; open-file rooks heuristic — translates material into decisive pressure.)
    • 7. Verify0 tok · 0ms

      Alle 3 Kandidaten legal. cloud_eval disabled (default).

      • chess.js.legal_recheck0ms
    • 8. Reflect187 tok · 9061ms · claude-sonnet-4-6 · $0.0028

      Final pick: gxf3 — King safety first: Bf3 threatens Bg2# next move. Capturing eliminates Black's only infiltrating piece, opens g-file for Rf1, and removes immediate mating threats before activating rooks.. Rejected: f7d…

      • llm.reflect9061ms · $0.0028
      full reasoning
      Final pick: gxf3 — King safety first: Bf3 threatens Bg2# next move. Capturing eliminates Black's only infiltrating piece, opens g-file for Rf1, and removes immediate mating threats before activating rooks.. Rejected: f7d5, f1e1.
    • 9. Commit0 tok · 0ms

      Commit gxf3 (g2f3).

  22. 22...Nd5Haiku13.891 tok · $0.0693 · 128885ms
    • 1. Observe0 tok · 1ms

      Halbzug 22, Schwarz am Zug. Phase: Mittelspiel. Weiss +2 Punkte. Legale Zuege: 29. Criticality: 0.00.

      • material-counter0ms
    • 2. Recall Position0 tok · 15ms

      recall: 5 similar position(s) found (limit=5).

      • nex_search15ms
    • 3. Recall Opponent0 tok · 5ms

      No pattern found for chess-sonnet-tm (tag=chess-sonnet-tm) — mandatory run documented.

      • nex_entity_search5ms
    • 4. Research0 tok · 0ms · skipped

      middlegame/endgame — research not relevant when both tools off.

    • 5. Plan2972 tok · 31244ms · claude-haiku-4-5 · $0.0148

      Phase: middlegame. Activate knight to e2 or d5, creating threats against White's king and pieces. Force advantageous exchanges while maintaining piece coordination. Aim for simplification into endgame where Black's centr…

      • llm.plan31244ms · $0.0148
      full reasoning
      Phase: middlegame. Activate knight to e2 or d5, creating threats against White's king and pieces. Force advantageous exchanges while maintaining piece coordination. Aim for simplification into endgame where Black's centralized knight and rook activity compensate for material deficit. Simplify into endgame where Black's piece activity and pawn tension offset material disadvantage; exploit White's advanced f3 pawn and king-side weaknesses. Critical: White's Bf7 dominates rank 7 and e8-escape—must address via tactical pressure; Black's Kc7 exposed to back-rank/king-safety tactics; stay alert; Knight centralization (Ne2+ or Nd5) is Black's only concrete asset for counterplay; White's f3 pawn is advanced but weak if isolated; target it.
    • 6. Candidates3802 tok · 35777ms · claude-haiku-4-5 · $0.0190

      Candidates: Nd5 (Knight centralization per plan; controls key squares, Black's only concrete counterplay asset) | Ne4 (Active knight creating immediate threats against White's king-side and f2 weakness) | e5 (Pawn advanc…

      • chess.js.legal_moves0ms
      • llm.candidates35775ms · $0.0190
      full reasoning
      Candidates: Nd5 (Knight centralization per plan; controls key squares, Black's only concrete counterplay asset) | Ne4 (Active knight creating immediate threats against White's king-side and f2 weakness) | e5 (Pawn advance controls d4, creates space for piece coordination, supports endgame simplification)
    • 7. Verify0 tok · 1ms

      Alle 3 Kandidaten legal. cloud_eval disabled (default).

      • chess.js.legal_recheck0ms
    • 8. Reflect7117 tok · 61826ms · claude-haiku-4-5 · $0.0355

      Final pick: Nd5 — Centralizes knight per explicit plan; controls key squares d5 and enables f4/e3 maneuvers targeting weak f3; coordinates pieces for endgame.. Rejected: f6e4, e7e5.

      • llm.reflect61826ms · $0.0355
    • 9. Commit0 tok · 0ms

      Commit Nd5 (f6d5).

  23. 23.Bxd5Sonnet798 tok · $0.0119 · 37726ms
    • 1. Observe0 tok · 0ms

      Halbzug 23, Weiss am Zug. Phase: Mittelspiel. Weiss +2 Punkte. Legale Zuege: 22. Criticality: 0.00.

      • material-counter0ms
    • 2. Recall Position0 tok · 16ms

      recall: 5 similar position(s) found (limit=5).

      • nex_search16ms
    • 3. Recall Opponent0 tok · 5ms

      No pattern found for chess-haiku-tm (tag=chess-haiku-tm) — mandatory run documented.

      • nex_entity_search5ms
    • 4. Research0 tok · 0ms · skipped

      middlegame/endgame — research not relevant when both tools off.

    • 5. Plan348 tok · 13386ms · claude-sonnet-4-6 · $0.0052

      Phase: middlegame. Activate both rooks onto the open d- and e-files to create decisive back-rank threats against Black's exposed king on c7, while the Bf7 anchors deep in Black's camp. Target: eliminate or neutralize the…

      • llm.plan13386ms · $0.0052
      full reasoning
      Phase: middlegame. Activate both rooks onto the open d- and e-files to create decisive back-rank threats against Black's exposed king on c7, while the Bf7 anchors deep in Black's camp. Target: eliminate or neutralize the Nd5 which is Black's only active piece, then coordinate rooks for a mating or material-winning attack. Convert the +2 material advantage by mobilizing rooks onto open files (open-file rooks heuristic) pointing at the c7-king, using the Bf7 as a permanent pin-anchor while the Nd5 is forced into passivity or traded off. Critical: Black's Nd5 is the sole active defender — removing or blockading it collapses Black's resistance; Open d-file and semi-open e-file are uncontested — rooks must occupy these immediately per open-file rooks heuristic; Black's king on c7 is exposed; Bf7 already dominates, so rook penetration to d7 or e7 could be decisive; Own king on g1 is safe — no counter-threats exist, so full-speed activation is correct; Doubled or backward pawns on Black's queenside are long-term liabilities but secondary to the immediate king-attack plan.
    • 6. Candidates258 tok · 14404ms · claude-sonnet-4-6 · $0.0038

      Candidates: Bxd5 (Eliminates Black's only active piece (Nd5), collapsing resistance; open-file rooks heuristic then decisive on d/e files.) | Rd1 (Activates rook on open d-file per open-file rooks heuristic, targeting ex…

      • chess.js.legal_moves0ms
      • llm.candidates14403ms · $0.0038
      full reasoning
      Candidates: Bxd5 (Eliminates Black's only active piece (Nd5), collapsing resistance; open-file rooks heuristic then decisive on d/e files.) | Rd1 (Activates rook on open d-file per open-file rooks heuristic, targeting exposed c7-king with immediate pressure.) | Re1 (Rook to semi-open e-file supports e7 penetration; king on g1 is safe so full-speed activation is correct.)
    • 7. Verify0 tok · 1ms

      Alle 3 Kandidaten legal. cloud_eval disabled (default).

      • chess.js.legal_recheck0ms
    • 8. Reflect192 tok · 9901ms · claude-sonnet-4-6 · $0.0028

      Final pick: Bxd5 — Eliminates Black's sole active piece; per open-file rooks heuristic, removing Nd5 immediately opens d/e files for both rooks against the exposed c7-king with no defensive resource left.. Rejected: f1d1…

      • llm.reflect9901ms · $0.0028
      full reasoning
      Final pick: Bxd5 — Eliminates Black's sole active piece; per open-file rooks heuristic, removing Nd5 immediately opens d/e files for both rooks against the exposed c7-king with no defensive resource left.. Rejected: f1d1, f1e1.
    • 9. Commit0 tok · 0ms

      Commit Bxd5 (f7d5).

  24. 24...e5Haiku10.126 tok · $0.0505 · 105130ms
    • 1. Observe0 tok · 0ms

      Halbzug 24, Schwarz am Zug. Phase: Mittelspiel. Weiss +5 Punkte. Legale Zuege: 21. Criticality: 0.00.

      • material-counter0ms
    • 2. Recall Position0 tok · 12ms

      recall: 5 similar position(s) found (limit=5).

      • nex_search12ms
    • 3. Recall Opponent0 tok · 5ms

      No pattern found for chess-sonnet-tm (tag=chess-sonnet-tm) — mandatory run documented.

      • nex_entity_search5ms
    • 4. Research0 tok · 0ms · skipped

      middlegame/endgame — research not relevant when both tools off.

    • 5. Plan4147 tok · 44503ms · claude-haiku-4-5 · $0.0207

      Phase: middlegame. Activate rooks on a- and e-files. Target f3 weakness and White's king. Force exchanges to reduce material deficit. Simplify toward endgame where Black's piece activity and rook centralization offset ma…

      • llm.plan44503ms · $0.0207
      full reasoning
      Phase: middlegame. Activate rooks on a- and e-files. Target f3 weakness and White's king. Force exchanges to reduce material deficit. Simplify toward endgame where Black's piece activity and rook centralization offset material disadvantage. Critical: Bd5 dominates—apply pressure or exchange it; Kc7 exposed on rank 7 to back-rank tactics; Rooks undeveloped—critical for counterplay; f3 advanced pawn is a potential weakness; White holds initiative—must generate immediate threats.
    • 6. Candidates4088 tok · 36314ms · claude-haiku-4-5 · $0.0204

      Candidates: e5 (Forces Bd5 to move, attacks dominant piece, simplifies and initiates central counterplay immediately.) | Rc8 (Activates rook on central c-file, prepares pressure on White's pieces and queenside counter-th…

      • chess.js.legal_moves0ms
      • llm.candidates36313ms · $0.0204
      full reasoning
      Candidates: e5 (Forces Bd5 to move, attacks dominant piece, simplifies and initiates central counterplay immediately.) | Rc8 (Activates rook on central c-file, prepares pressure on White's pieces and queenside counter-threats.) | Re8 (Develops rook on e-file per plan, supports e5 thrust, targets f3 weakness and generates rook pressure.)
    • 7. Verify0 tok · 1ms

      Alle 3 Kandidaten legal. cloud_eval disabled (default).

      • chess.js.legal_recheck0ms
    • 8. Reflect1891 tok · 24285ms · claude-haiku-4-5 · $0.0094

      Final pick: e5 — e5 attacks Bd5, forcing White's dominant piece to move or exchange. Immediately simplifies position and seizes central initiative, directly reducing material via likely Bxe5 capture.. Rejected: a8c8, a8e…

      • llm.reflect24285ms · $0.0094
      full reasoning
      Final pick: e5 — e5 attacks Bd5, forcing White's dominant piece to move or exchange. Immediately simplifies position and seizes central initiative, directly reducing material via likely Bxe5 capture.. Rejected: a8c8, a8e8.
    • 9. Commit0 tok · 0ms

      Commit e5 (e7e5).

  25. 25.Rd1Sonnet787 tok · $0.0117 · 33410ms
    • 1. Observe0 tok · 0ms

      Halbzug 25, Weiss am Zug. Phase: Mittelspiel. Weiss +5 Punkte. Legale Zuege: 24. Criticality: 0.00.

      • material-counter0ms
    • 2. Recall Position0 tok · 15ms

      recall: 5 similar position(s) found (limit=5).

      • nex_search15ms
    • 3. Recall Opponent0 tok · 5ms

      No pattern found for chess-haiku-tm (tag=chess-haiku-tm) — mandatory run documented.

      • nex_entity_search5ms
    • 4. Research0 tok · 0ms · skipped

      middlegame/endgame — research not relevant when both tools off.

    • 5. Plan321 tok · 13888ms · claude-sonnet-4-6 · $0.0048

      Phase: middlegame. Activate both rooks on the open d- and e-files to press the exposed Black king on c7. The Bd5 (likely the bishop anchored deep) serves as a permanent positional anchor. Coordinate rooks for back-rank p…

      • llm.plan13888ms · $0.0048
      full reasoning
      Phase: middlegame. Activate both rooks on the open d- and e-files to press the exposed Black king on c7. The Bd5 (likely the bishop anchored deep) serves as a permanent positional anchor. Coordinate rooks for back-rank pressure while Black's pieces remain passive and uncoordinated. Convert the +5 material advantage by doubling rooks on open files pointing at the c7-king, using the deep bishop as a permanent positional anchor, while preventing any Black counterplay. Critical: Black king on c7 is exposed — open-file rooks heuristic demands immediate rook activation on d1/e1 or similar open lines pressing toward c7; Black's e5-pawn is isolated and potentially weak — target it with rook pressure (IQP heuristic: blockade + attack the isolani); Own king on g1 is safe — no defensive obligations, all energy goes into the attack; Black's rooks on a8/h8 are completely undeveloped — time advantage must be exploited before they coordinate; No immediate tactical threats from Black to worry about.
    • 6. Candidates254 tok · 10455ms · claude-sonnet-4-6 · $0.0038

      Candidates: Rd1 (Open-file rooks heuristic: Rd1 activates rook on the d-file pointing directly at exposed Black king on c7.) | Bxb7 (Deep bishop as positional anchor converts material advantage; wins pawn while maintaini…

      • chess.js.legal_moves0ms
      • llm.candidates10453ms · $0.0038
      full reasoning
      Candidates: Rd1 (Open-file rooks heuristic: Rd1 activates rook on the d-file pointing directly at exposed Black king on c7.) | Bxb7 (Deep bishop as positional anchor converts material advantage; wins pawn while maintaining bishop activity pressing Black's position.) | Re1 (Rook activation on e-file targets isolated e5-pawn (IQP heuristic: attack the isolani) before Black's undeveloped rooks coordinate.)
    • 7. Verify0 tok · 0ms

      Alle 3 Kandidaten legal. cloud_eval disabled (default).

      • chess.js.legal_recheck0ms
    • 8. Reflect212 tok · 9026ms · claude-sonnet-4-6 · $0.0031

      Final pick: Rd1 — Open-file rooks heuristic: Rd1 places the rook on the d-file aiming directly at the exposed Black king on c7. The Bd5 anchor controls the d-file approach; doubling pressure there is more forcing than e-…

      • llm.reflect9026ms · $0.0031
      full reasoning
      Final pick: Rd1 — Open-file rooks heuristic: Rd1 places the rook on the d-file aiming directly at the exposed Black king on c7. The Bd5 anchor controls the d-file approach; doubling pressure there is more forcing than e-file or pawn capture.. Rejected: d5b7, f1e1.
    • 9. Commit0 tok · 0ms

      Commit Rd1 (f1d1).

  26. 26...e4Haiku10.506 tok · $0.0524 · 101627ms
    • 1. Observe0 tok · 0ms

      Halbzug 26, Schwarz am Zug. Phase: Mittelspiel. Weiss +5 Punkte. Legale Zuege: 25. Criticality: 0.00.

      • material-counter0ms
    • 2. Recall Position0 tok · 16ms

      recall: 5 similar position(s) found (limit=5).

      • nex_search16ms
    • 3. Recall Opponent0 tok · 7ms

      No pattern found for chess-sonnet-tm (tag=chess-sonnet-tm) — mandatory run documented.

      • nex_entity_search7ms
    • 4. Research0 tok · 0ms · skipped

      middlegame/endgame — research not relevant when both tools off.

    • 5. Plan4981 tok · 46789ms · claude-haiku-4-5 · $0.0249

      Phase: middlegame. Attack f3 pawn with ...e4 to force complications and weaken White's kingside. Activate rooks on a- and e-files in parallel to generate immediate counterplay. Trade down material while keeping rooks cen…

      • llm.plan46789ms · $0.0249
      full reasoning
      Phase: middlegame. Attack f3 pawn with ...e4 to force complications and weaken White's kingside. Activate rooks on a- and e-files in parallel to generate immediate counterplay. Trade down material while keeping rooks centralized and active, transforming material deficit into piece coordination advantage in the endgame. Critical: f3 pawn is advanced and weak—...e4 attacks it directly, forcing White to defend or exchange; Bd5 is White's strong piece dominating light squares—must neutralize via piece exchanges or tactical pressure; Ra8 and Rh8 are dormant—their activation on open/half-open files is the key to generating sufficient counterplay.
    • 6. Candidates2877 tok · 28802ms · claude-haiku-4-5 · $0.0143

      Candidates: e4 (Forces White defend or exchange f3 pawn, weakens kingside, generates immediate tactical complications.) | Rc8 (Activates queen's rook toward center, pressures c-file, prepares coordinated rook counterplay…

      • chess.js.legal_moves0ms
      • llm.candidates28799ms · $0.0143
      full reasoning
      Candidates: e4 (Forces White defend or exchange f3 pawn, weakens kingside, generates immediate tactical complications.) | Rc8 (Activates queen's rook toward center, pressures c-file, prepares coordinated rook counterplay.) | Re8 (Activates king's rook on e-file, maintains pressure on weak structure, enables rook coordination.)
    • 7. Verify0 tok · 1ms

      Alle 3 Kandidaten legal. cloud_eval disabled (default).

      • chess.js.legal_recheck0ms
    • 8. Reflect2648 tok · 25992ms · claude-haiku-4-5 · $0.0132

      Final pick: e4 — e4 directly attacks the weak f3 pawn, forcing White to defend, exchange, or retreat. Creates immediate tactical blow and kingside weakening—tactically forcing.. Rejected: a8c8, a8e8.

      • llm.reflect25992ms · $0.0132
    • 9. Commit0 tok · 0ms

      Commit e4 (e5e4).

  27. 27.Bxb7Sonnet756 tok · $0.0112 · 33874ms
    • 1. Observe0 tok · 0ms

      Halbzug 27, Weiss am Zug. Phase: Mittelspiel. Weiss +5 Punkte. Legale Zuege: 26. Criticality: 0.00.

      • material-counter0ms
    • 2. Recall Position0 tok · 11ms

      recall: 5 similar position(s) found (limit=5).

      • nex_search11ms
    • 3. Recall Opponent0 tok · 8ms

      No pattern found for chess-haiku-tm (tag=chess-haiku-tm) — mandatory run documented.

      • nex_entity_search8ms
    • 4. Research0 tok · 0ms · skipped

      middlegame/endgame — research not relevant when both tools off.

    • 5. Plan318 tok · 12864ms · claude-sonnet-4-6 · $0.0047

      Phase: middlegame. Activate both rooks on the open d- and e-files to press the exposed Black king on c7. The Bd5 serves as a permanent positional anchor controlling key squares. Coordinate rooks to create back-rank and f…

      • llm.plan12864ms · $0.0047
      full reasoning
      Phase: middlegame. Activate both rooks on the open d- and e-files to press the exposed Black king on c7. The Bd5 serves as a permanent positional anchor controlling key squares. Coordinate rooks to create back-rank and file pressure while Black remains passive. Convert +5 material advantage into a decisive attack. Double rooks on the d-file or e-file pointing directly at the c7-king, use Bd5 as an unassailable anchor, and force Black into zugzwang or decisive material loss — the open-file rooks heuristic is the structural backbone of this conversion. Critical: Black king on c7 is exposed — rook activation on open d/e-files is the primary threat vector (open-file rooks heuristic, memory hit 1); Black's e4-pawn is advanced but isolated — it is not an IQP threat to us but a potential target if rooks control the e-file; Black has no coordinated counterplay; Rf8 is passive and a8-rook is dormant — no immediate opponent threats to neutralize before proceeding.
    • 6. Candidates259 tok · 8862ms · claude-sonnet-4-6 · $0.0038

      Candidates: Re1 (Activates rook on open e-file, pressuring Black's e4-pawn and pointing at exposed c7-king. Open-file rooks heuristic.) | Bxb7 (Captures free pawn, destroys Black's queenside, keeps Bd5 anchor role after …

      • chess.js.legal_moves0ms
      • llm.candidates8861ms · $0.0038
      full reasoning
      Candidates: Re1 (Activates rook on open e-file, pressuring Black's e4-pawn and pointing at exposed c7-king. Open-file rooks heuristic.) | Bxb7 (Captures free pawn, destroys Black's queenside, keeps Bd5 anchor role after recapture while gaining material.) | Bxe4 (Removes isolated e4-pawn target, opens e-file for rook activation consistent with open-file rooks heuristic.)
    • 7. Verify0 tok · 0ms

      Alle 3 Kandidaten legal. cloud_eval disabled (default).

      • chess.js.legal_recheck0ms
    • 8. Reflect179 tok · 12114ms · claude-sonnet-4-6 · $0.0026

      Final pick: Bxb7 — Wins a free pawn AND destroys Black's queenside structure. After Bxb7 Ra7 we recapture and remain up material with rooks still activatable. Trade only when you gain — this gains concrete material.. Rej…

      • llm.reflect12114ms · $0.0026
      full reasoning
      Final pick: Bxb7 — Wins a free pawn AND destroys Black's queenside structure. After Bxb7 Ra7 we recapture and remain up material with rooks still activatable. Trade only when you gain — this gains concrete material.. Rejected: d1e1, d5e4.
    • 9. Commit0 tok · 0ms

      Commit Bxb7 (d5b7).

  28. 28...Kxb7Haiku9.303 tok · $0.0464 · 90786ms
    • 1. Observe0 tok · 0ms

      Halbzug 28, Schwarz am Zug. Phase: Mittelspiel. Weiss +6 Punkte. Legale Zuege: 24. Criticality: 0.00.

      • material-counter0ms
    • 2. Recall Position0 tok · 22ms

      recall: 5 similar position(s) found (limit=5).

      • nex_search22ms
    • 3. Recall Opponent0 tok · 15ms

      No pattern found for chess-sonnet-tm (tag=chess-sonnet-tm) — mandatory run documented.

      • nex_entity_search15ms
    • 4. Research0 tok · 0ms · skipped

      middlegame/endgame — research not relevant when both tools off.

    • 5. Plan3892 tok · 35541ms · claude-haiku-4-5 · $0.0194

      Phase: middlegame. Activate dormant rooks (Ra8, Rh8) on a-file and e-file. Maintain pressure on f3 pawn. Force White to commit to defending or trading. Generate immediate tactical complications. Transform material defici…

      • llm.plan35541ms · $0.0194
      full reasoning
      Phase: middlegame. Activate dormant rooks (Ra8, Rh8) on a-file and e-file. Maintain pressure on f3 pawn. Force White to commit to defending or trading. Generate immediate tactical complications. Transform material deficit into active rook coordination and pawn play, reaching an endgame where Black has practical chances via rook activity. Critical: Opponent threat: Bb7 dominates light squares on 7th rank, preventing Black's pieces from coordinating; Own weakness: Material deficit (bishop + 3 pawns) requires immediate compensation via piece activity; Concrete tactical threat: e4 pawn attacks f3; if White defends passively, Black activates rooks on open files.
    • 6. Candidates1915 tok · 18919ms · claude-haiku-4-5 · $0.0095

      Candidates: Kxb7 (Capture the dominant light-square bishop. Eliminates White's key piece; reduces material deficit and activates king.) | exf3 (Eliminate f3 pawn, maintain tactical pressure, reduce White pawn count and c…

      • chess.js.legal_moves0ms
      • llm.candidates18917ms · $0.0095
      full reasoning
      Candidates: Kxb7 (Capture the dominant light-square bishop. Eliminates White's key piece; reduces material deficit and activates king.) | exf3 (Eliminate f3 pawn, maintain tactical pressure, reduce White pawn count and create tactical complications.) | Rb8 (Activate dormant rook on a-file; coordinate with king after Kxb7; build piece activity for compensation.)
    • 7. Verify0 tok · 1ms

      Alle 3 Kandidaten legal. cloud_eval disabled (default).

      • chess.js.legal_recheck0ms
    • 8. Reflect3496 tok · 36267ms · claude-haiku-4-5 · $0.0174

      Final pick: Kxb7 — Eliminates White's dominant light-squared bishop, activates the king, reduces material deficit. Most forcing move in a position where compensation requires eliminating key pieces.. Rejected: e4f3, a8b8…

      • llm.reflect36267ms · $0.0174
      full reasoning
      Final pick: Kxb7 — Eliminates White's dominant light-squared bishop, activates the king, reduces material deficit. Most forcing move in a position where compensation requires eliminating key pieces.. Rejected: e4f3, a8b8.
    • 9. Commit0 tok · 0ms

      Commit Kxb7 (c7b7).

  29. 29.fxe4Sonnet707 tok · $0.0105 · 43736ms
    • 1. Observe0 tok · 0ms

      Halbzug 29, Weiss am Zug. Phase: Mittelspiel. Weiss +3 Punkte. Legale Zuege: 18. Criticality: 0.00.

      • material-counter0ms
    • 2. Recall Position0 tok · 10ms

      recall: 5 similar position(s) found (limit=5).

      • nex_search10ms
    • 3. Recall Opponent0 tok · 8ms

      No pattern found for chess-haiku-tm (tag=chess-haiku-tm) — mandatory run documented.

      • nex_entity_search8ms
    • 4. Research0 tok · 0ms · skipped

      middlegame/endgame — research not relevant when both tools off.

    • 5. Plan262 tok · 16852ms · claude-sonnet-4-6 · $0.0039

      Phase: middlegame. Activate rooks on open d/e-files, press the exposed Black king on c7/b7, convert +3 material into a decisive attack within 3-5 moves by doubling rooks or penetrating to 7th/8th rank. Use open-file rook…

      • llm.plan16852ms · $0.0039
      full reasoning
      Phase: middlegame. Activate rooks on open d/e-files, press the exposed Black king on c7/b7, convert +3 material into a decisive attack within 3-5 moves by doubling rooks or penetrating to 7th/8th rank. Use open-file rook dominance (heuristic: rooks belong on open lines) to create unstoppable back-rank threats against the passive Black king, converting material advantage into a forced win. Critical: Black king on b7 is exposed with limited cover; Open d-file and e-file must be occupied immediately — open file rooks heuristic is the structural backbone; Black e4-pawn is a passed passer that could become dangerous if ignored; Own king on g1 is safe — no king-safety concerns for White; Black Bf8 is passive and disconnected — doubled rook pressure will overwhelm it.
    • 6. Candidates256 tok · 17422ms · claude-sonnet-4-6 · $0.0038

      Candidates: fxe4 (Captures dangerous passed pawn immediately; open-file rooks heuristic: opens f-file for rook activation toward exposed Black king.) | Re1 (Activates rook on open e-file, pressing toward e4-pawn and Blac…

      • chess.js.legal_moves0ms
      • llm.candidates17421ms · $0.0038
      full reasoning
      Candidates: fxe4 (Captures dangerous passed pawn immediately; open-file rooks heuristic: opens f-file for rook activation toward exposed Black king.) | Re1 (Activates rook on open e-file, pressing toward e4-pawn and Black king on b7; open-file dominance is structural backbone of plan.) | d4 (Advances central pawn, supports rook penetration and restricts Black; improves worst piece while king safety on g1 is secure.)
    • 7. Verify0 tok · 1ms

      Alle 3 Kandidaten legal. cloud_eval disabled (default).

      • chess.js.legal_recheck0ms
    • 8. Reflect189 tok · 9432ms · claude-sonnet-4-6 · $0.0028

      Final pick: fxe4 — Eliminates the dangerous passed e4-pawn immediately — open-file rooks heuristic: opens f-file for rook, removes Black's only counterplay. Material stays +3, king on g1 safe, Black position collapses.. …

      • llm.reflect9432ms · $0.0028
      full reasoning
      Final pick: fxe4 — Eliminates the dangerous passed e4-pawn immediately — open-file rooks heuristic: opens f-file for rook, removes Black's only counterplay. Material stays +3, king on g1 safe, Black position collapses.. Rejected: d1e1, d2d4.
    • 9. Commit0 tok · 0ms

      Commit fxe4 (f3e4).

  30. 30...Rc8Haiku10.023 tok · $0.0500 · 100406ms
    • 1. Observe0 tok · 0ms

      Halbzug 30, Schwarz am Zug. Phase: Mittelspiel. Weiss +4 Punkte. Legale Zuege: 22. Criticality: 0.10.

      • material-counter0ms
    • 2. Recall Position0 tok · 12ms

      recall: 5 similar position(s) found (limit=5).

      • nex_search12ms
    • 3. Recall Opponent0 tok · 7ms

      No pattern found for chess-sonnet-tm (tag=chess-sonnet-tm) — mandatory run documented.

      • nex_entity_search7ms
    • 4. Research0 tok · 0ms · skipped

      middlegame/endgame — research not relevant when both tools off.

    • 5. Plan3355 tok · 30355ms · claude-haiku-4-5 · $0.0167

      Phase: middlegame. Activate dormant rooks on half-open a-file and 5th rank. Push f6 to gain space and prepare e-file control. Force White into defensive posture via rook threats. Create practical complications where coor…

      • llm.plan30355ms · $0.0167
      full reasoning
      Phase: middlegame. Activate dormant rooks on half-open a-file and 5th rank. Push f6 to gain space and prepare e-file control. Force White into defensive posture via rook threats. Create practical complications where coordination compensates for material deficit. Transform material disadvantage into dynamic rook activity. Establish rooks on a5, c8, or 5th rank. Control open lines, restrict White's king, and generate endgame positions where rook play + pawn breaks (f6, a5) create winning chances. Critical: e4 pawn undefended, controls space; dormant rooks must activate immediately or White consolidates; White can push e5 or activate Ra1/Rd1, restricting Black's mobility; Black must generate threats (rook forks, f6 pawn break) within 3-4 moves or lose to attrition.
    • 6. Candidates4407 tok · 37298ms · claude-haiku-4-5 · $0.0220

      Candidates: Rc8 (Rook activation toward center. Supports e-file/c-file control. Reduces White's consolidation tempo while maintaining line pressure.) | a5 (Pawn break gains queenside space. Enables future rook infiltrati…

      • chess.js.legal_moves0ms
      • llm.candidates37297ms · $0.0220
      full reasoning
      Candidates: Rc8 (Rook activation toward center. Supports e-file/c-file control. Reduces White's consolidation tempo while maintaining line pressure.) | a5 (Pawn break gains queenside space. Enables future rook infiltration on a-file; forces White into passive rook defense.) | Rb8 (Rook activation on half-open a-file. Maintains pressure; prepares a5 support while keeping options open for infiltration.)
    • 7. Verify0 tok · 0ms

      Alle 3 Kandidaten legal. cloud_eval disabled (default).

      • chess.js.legal_recheck0ms
    • 8. Reflect2261 tok · 32719ms · claude-haiku-4-5 · $0.0113

      Final pick: Rc8 — Centralizes rook immediately; opens a-file, prepares e-file/5th-rank control, forces White into reactive defense. Rejected: a7a5, a8b8.

      • llm.reflect32719ms · $0.0113
    • 9. Commit0 tok · 0ms

      Commit Rc8 (a8c8).

  31. 31.Re1Sonnet702 tok · $0.0104 · 30233ms
    • 1. Observe0 tok · 0ms

      Halbzug 31, Weiss am Zug. Phase: Mittelspiel. Weiss +4 Punkte. Legale Zuege: 19. Criticality: 0.10.

      • material-counter0ms
    • 2. Recall Position0 tok · 15ms

      recall: 5 similar position(s) found (limit=5).

      • nex_search15ms
    • 3. Recall Opponent0 tok · 14ms

      No pattern found for chess-haiku-tm (tag=chess-haiku-tm) — mandatory run documented.

      • nex_entity_search14ms
    • 4. Research0 tok · 0ms · skipped

      middlegame/endgame — research not relevant when both tools off.

    • 5. Plan251 tok · 10384ms · claude-sonnet-4-6 · $0.0037

      Phase: middlegame. Activate both rooks on open d/e-files, penetrate to 7th rank, press the exposed Black king on b7/c7 into a decisive back-rank mating net within 3-4 moves Convert +4 material into a forced win by doubli…

      • llm.plan10384ms · $0.0037
      full reasoning
      Phase: middlegame. Activate both rooks on open d/e-files, penetrate to 7th rank, press the exposed Black king on b7/c7 into a decisive back-rank mating net within 3-4 moves Convert +4 material into a forced win by doubling rooks on open files (open-file rooks heuristic is structural backbone) and exploiting the naked Black king with no defensive cover Critical: Black king on b7 is exposed with no pawn shelter — rook penetration to 7th rank may be immediately decisive; Open d-file and e-file must be occupied now per open-file rooks heuristic — rooks on a1/f1 are currently passive; Black bishop on f8 and rook on h8 are disconnected and passive — no counterplay threat to delay our plan.
    • 6. Candidates262 tok · 10389ms · claude-sonnet-4-6 · $0.0039

      Candidates: Re1 (Activates rook on open e-file per open-file rooks heuristic; threatens Re7+ penetrating to 7th rank against exposed Black king on b7.) | e5 (Space gain opens lines toward Black's position; pawn advance s…

      • chess.js.legal_moves0ms
      • llm.candidates10389ms · $0.0039
      full reasoning
      Candidates: Re1 (Activates rook on open e-file per open-file rooks heuristic; threatens Re7+ penetrating to 7th rank against exposed Black king on b7.) | e5 (Space gain opens lines toward Black's position; pawn advance supports rook penetration and restricts Black's passive bishop on f8.) | d4 (Opens the d-file for Ra1 activation per open-file rooks heuristic; doubling rooks on d/e files builds decisive pressure on naked Black king.)
    • 7. Verify0 tok · 1ms

      Alle 3 Kandidaten legal. cloud_eval disabled (default).

      • chess.js.legal_recheck0ms
    • 8. Reflect189 tok · 9414ms · claude-sonnet-4-6 · $0.0028

      Final pick: Re1 — Activates rook on open e-file immediately per open-file rooks heuristic. Re7+ next move penetrates 7th rank against the naked Black king on b7 — concrete forced pressure before Black can consolidate.. R…

      • llm.reflect9413ms · $0.0028
      full reasoning
      Final pick: Re1 — Activates rook on open e-file immediately per open-file rooks heuristic. Re7+ next move penetrates 7th rank against the naked Black king on b7 — concrete forced pressure before Black can consolidate.. Rejected: e4e5, d2d4.
    • 9. Commit0 tok · 0ms

      Commit Re1 (d1e1).

  32. 32...Rxc2Haiku15.432 tok · $0.0771 · 143085ms
    • 1. Observe0 tok · 0ms

      Halbzug 32, Schwarz am Zug. Phase: Mittelspiel. Weiss +4 Punkte. Legale Zuege: 28. Criticality: 0.10.

      • material-counter0ms
    • 2. Recall Position0 tok · 20ms

      recall: 5 similar position(s) found (limit=5).

      • nex_search20ms
    • 3. Recall Opponent0 tok · 10ms

      No pattern found for chess-sonnet-tm (tag=chess-sonnet-tm) — mandatory run documented.

      • nex_entity_search10ms
    • 4. Research0 tok · 0ms · skipped

      middlegame/endgame — research not relevant when both tools off.

    • 5. Plan4315 tok · 39251ms · claude-haiku-4-5 · $0.0215

      Phase: middlegame. Push a5 to activate a-file. Move c8 rook to c5 or c4 to pressure e4. Coordinate rooks to create tactical complications. Force White into defensive mode. Compensate for material deficit through piece ac…

      • llm.plan39251ms · $0.0215
      full reasoning
      Phase: middlegame. Push a5 to activate a-file. Move c8 rook to c5 or c4 to pressure e4. Coordinate rooks to create tactical complications. Force White into defensive mode. Compensate for material deficit through piece activity and tempo. Build rook + pawn endgame where coordinated rooks on open files and advanced a-pawn overcome material disadvantage through practical winning chances. Critical: White's pieces underdeveloped (bishop c1 inactive, rooks uncoordinated). E4 pawn controls space but is pressure point for rook invasion.; Black's rooks dormant (c8, h8). Missing f-pawn = kingside weakness. Only 3 pawns limits pawn play options.; Concrete tactic: a5 opens a-file for rook pressure. Rc5/Rc4 attacks e4 and restricts White rook. Dual rook threats create practical complications..
    • 6. Candidates3130 tok · 32398ms · claude-haiku-4-5 · $0.0156

      Candidates: Rc5 (Attacks e4 directly, restricts White's rook, forces immediate defensive response, creates dual rook threat complications) | a5 (Opens a-file for rook pressure, activates dangerous passed pawn, builds fou…

      • chess.js.legal_moves0ms
      • llm.candidates32396ms · $0.0156
      full reasoning
      Candidates: Rc5 (Attacks e4 directly, restricts White's rook, forces immediate defensive response, creates dual rook threat complications) | a5 (Opens a-file for rook pressure, activates dangerous passed pawn, builds foundation for rook+pawn endgame compensation) | Rxc2 (Wins c2 pawn immediately, reduces material deficit, seizes second rank with forcing tactical threats)
    • 7. Verify0 tok · 1ms

      Alle 3 Kandidaten legal. cloud_eval disabled (default).

      • chess.js.legal_recheck0ms
    • 8. Reflect7987 tok · 71385ms · claude-haiku-4-5 · $0.0399

      Final pick: Rxc2 — Captures undefended hanging pawn c2. Wins material immediately (−6 to −5). Rook seizes second rank, attacks b2/d2, creates forcing complications. Concrete material gain.. Rejected: c8c5, a7a5.

      • llm.reflect71385ms · $0.0399
    • 9. Commit0 tok · 0ms

      Commit Rxc2 (c8c2).

  33. 33.Re2Sonnet712 tok · $0.0106 · 36333ms
    • 1. Observe0 tok · 0ms

      Halbzug 33, Weiss am Zug. Phase: Mittelspiel. Weiss +3 Punkte. Legale Zuege: 19. Criticality: 0.10.

      • material-counter0ms
    • 2. Recall Position0 tok · 12ms

      recall: 5 similar position(s) found (limit=5).

      • nex_search12ms
    • 3. Recall Opponent0 tok · 17ms

      No pattern found for chess-haiku-tm (tag=chess-haiku-tm) — mandatory run documented.

      • nex_entity_search17ms
    • 4. Research0 tok · 0ms · skipped

      middlegame/endgame — research not relevant when both tools off.

    • 5. Plan258 tok · 10393ms · claude-sonnet-4-6 · $0.0038

      Phase: middlegame. Activate rooks on open files (open-file rooks heuristic) — occupy d-file and e-file, penetrate to 7th rank targeting the naked Black king on b7. With +3 material, simplify into a won ending or force a …

      • llm.plan10393ms · $0.0038
      full reasoning
      Phase: middlegame. Activate rooks on open files (open-file rooks heuristic) — occupy d-file and e-file, penetrate to 7th rank targeting the naked Black king on b7. With +3 material, simplify into a won ending or force a mating net within 3-4 moves. Convert material advantage into a forced win by doubling rooks on the 7th rank, exploiting the completely unshielded Black king with no pawn cover on b7/c7. Critical: Black Rc2 is actively harassing White's 2nd rank — must address or counter with tempo; Black king on b7 has zero pawn shelter — rook on 7th rank is immediately decisive; Open-file rooks heuristic: Ra1 and Re1 are underutilized — e-file and d-file must be occupied now.
    • 6. Candidates261 tok · 10414ms · claude-sonnet-4-6 · $0.0039

      Candidates: Re2 (Expels Rc2 with tempo — open-file rooks heuristic: Re1 was idle, now threatens Re7+ targeting the naked king on b7.) | e5 (Advances passed pawn, gains space, opens lines for rooks — converts material adv…

      • chess.js.legal_moves0ms
      • llm.candidates10413ms · $0.0039
      full reasoning
      Candidates: Re2 (Expels Rc2 with tempo — open-file rooks heuristic: Re1 was idle, now threatens Re7+ targeting the naked king on b7.) | e5 (Advances passed pawn, gains space, opens lines for rooks — converts material advantage by creating a second threat.) | d4 (Occupies d-file per open-file rooks heuristic; pawn chain d4-e4 restricts Black, supports eventual Rd1-d7 penetration.)
    • 7. Verify0 tok · 1ms

      Alle 3 Kandidaten legal. cloud_eval disabled (default).

      • chess.js.legal_recheck0ms
    • 8. Reflect193 tok · 15477ms · claude-sonnet-4-6 · $0.0029

      Final pick: Re2 — Expels Rc2 with tempo (open-file rooks heuristic: Re1 was idle), immediately threatens Re7+ against the naked king on b7 with zero pawn shelter — forcing a decisive rook penetration.. Rejected: e4e5, d2…

      • llm.reflect15477ms · $0.0029
      full reasoning
      Final pick: Re2 — Expels Rc2 with tempo (open-file rooks heuristic: Re1 was idle), immediately threatens Re7+ against the naked king on b7 with zero pawn shelter — forcing a decisive rook penetration.. Rejected: e4e5, d2d4.
    • 9. Commit0 tok · 0ms

      Commit Re2 (e1e2).

  34. 34...Rxc1+Haiku12.843 tok · $0.0641 · 120858ms
    • 1. Observe0 tok · 0ms

      Halbzug 34, Schwarz am Zug. Phase: Mittelspiel. Weiss +3 Punkte. Legale Zuege: 28. Criticality: 0.10.

      • material-counter0ms
    • 2. Recall Position0 tok · 9ms

      recall: 5 similar position(s) found (limit=5).

      • nex_search9ms
    • 3. Recall Opponent0 tok · 5ms

      No pattern found for chess-sonnet-tm (tag=chess-sonnet-tm) — mandatory run documented.

      • nex_entity_search5ms
    • 4. Research0 tok · 0ms · skipped

      middlegame/endgame — research not relevant when both tools off.

    • 5. Plan3897 tok · 37739ms · claude-haiku-4-5 · $0.0194

      Phase: middlegame. Mobilize dormant kingside rook to open files. Push queenside pawn to create passed-pawn tension. Coordinate rooks to pressure e4 and White's underdeveloped pieces. Force White into passive defense with…

      • llm.plan37739ms · $0.0194
      full reasoning
      Phase: middlegame. Mobilize dormant kingside rook to open files. Push queenside pawn to create passed-pawn tension. Coordinate rooks to pressure e4 and White's underdeveloped pieces. Force White into passive defense within 3-5 moves. Transform active rook placement and advanced queenside pawn into a rook endgame where Black's coordinated piece activity and passed pawn overcome White's 3-pawn material advantage. Critical: White may entrap the active rook or consolidate piece coordination—Black must seize initiative before White stabilizes; Doubled kingside pawns limit mobility and bishop utility; queenside pawn is Black's sole counterplay asset; e4 pawn anchors White's space but remains the target for coordinated rook-pair pressure.
    • 6. Candidates2337 tok · 23782ms · claude-haiku-4-5 · $0.0116

      Candidates: Rxc1+ (Most forcing: removes bishop, checks king, seizes initiative. Forces White into passive defense immediately.) | Rc3 (Activates rook on open c-file, prepares to support a5 advance and coordinate dual ro…

      • chess.js.legal_moves0ms
      • llm.candidates23779ms · $0.0116
      full reasoning
      Candidates: Rxc1+ (Most forcing: removes bishop, checks king, seizes initiative. Forces White into passive defense immediately.) | Rc3 (Activates rook on open c-file, prepares to support a5 advance and coordinate dual rook pressure on e4.) | a5 (Advances queenside pawn, creates passed-pawn tension and concrete counterplay asset before White consolidates.)
    • 7. Verify0 tok · 1ms

      Alle 3 Kandidaten legal. cloud_eval disabled (default).

      • chess.js.legal_recheck0ms
    • 8. Reflect6609 tok · 59306ms · claude-haiku-4-5 · $0.0330

      Final pick: Rxc1+ — Wins White bishop with check, equalizing material (rook endgames favor 3P vs 1B). Seizes initiative, forces king move, Black coordinates rooks on open lines against e4.. Rejected: c2c3, a7a5.

      • llm.reflect59306ms · $0.0330
    • 9. Commit0 tok · 0ms

      Commit Rxc1+ (c2c1).

  35. 35.Rxc1Sonnet693 tok · $0.0103 · 37784ms
    • 1. Observe0 tok · 0ms

      Halbzug 35, Weiss am Zug. Phase: Mittelspiel. Material gleich. Legale Zuege: 3. Schach! Criticality: 0.70.

      • material-counter0ms
    • 2. Recall Position0 tok · 22ms

      recall: 5 similar position(s) found (limit=5).

      • nex_search22ms
    • 3. Recall Opponent0 tok · 16ms

      No pattern found for chess-haiku-tm (tag=chess-haiku-tm) — mandatory run documented.

      • nex_entity_search16ms
    • 4. Research0 tok · 0ms · skipped

      middlegame/endgame — research not relevant when both tools off.

    • 5. Plan253 tok · 11016ms · claude-sonnet-4-6 · $0.0038

      Phase: middlegame. With only 3 legal moves and Black's king nakedly exposed on b7, find the forcing continuation that either delivers checkmate or wins decisive material. The open-file rooks heuristic confirms Re7+ is th…

      • llm.plan11016ms · $0.0038
      full reasoning
      Phase: middlegame. With only 3 legal moves and Black's king nakedly exposed on b7, find the forcing continuation that either delivers checkmate or wins decisive material. The open-file rooks heuristic confirms Re7+ is the natural candidate — penetrating to the 7th rank with check exploits zero pawn shelter on b7. Drive rooks to the 7th rank to create a mating net around the unshielded Black king on b7, converting the initiative into a forced win before Black's Rc1 check becomes dangerous. Critical: Black king on b7 has no pawn cover — 7th rank penetration with check is immediately decisive; Only 3 legal moves exist — position is nearly forced, evaluate each for mating potential; Black Rc1 threatens back-rank pressure but White's king on g1 is safe enough to ignore if we act with tempo.
    • 6. Candidates246 tok · 9894ms · claude-sonnet-4-6 · $0.0037

      Candidates: Rxc1 (Eliminates Black's dangerous back-rank rook; open-file rook trade gains material clarity with king safe on g1.) | Re1 (Centralizes rook to e1, prepares to contest back rank; king safety heuristic: neutr…

      • chess.js.legal_moves0ms
      • llm.candidates9894ms · $0.0037
      full reasoning
      Candidates: Rxc1 (Eliminates Black's dangerous back-rank rook; open-file rook trade gains material clarity with king safe on g1.) | Re1 (Centralizes rook to e1, prepares to contest back rank; king safety heuristic: neutralize Rc1 pressure before advancing.) | Kg2 (Steps king off back rank, escaping any back-rank mating threats; improves king safety before rook coordination.)
    • 7. Verify0 tok · 0ms

      Alle 3 Kandidaten legal. cloud_eval disabled (default).

      • chess.js.legal_recheck0ms
    • 8. Reflect194 tok · 16816ms · claude-sonnet-4-6 · $0.0029

      Final pick: Rxc1 — Eliminates Black's active back-rank rook immediately, removing the only piece generating counter-play. King on g1 is safe post-trade; open c-file now belongs to White with Re2 free to penetrate to c2 o…

      • llm.reflect16816ms · $0.0029
      full reasoning
      Final pick: Rxc1 — Eliminates Black's active back-rank rook immediately, removing the only piece generating counter-play. King on g1 is safe post-trade; open c-file now belongs to White with Re2 free to penetrate to c2 or e7.. Rejected: e2e1, g1g2.
    • 9. Commit0 tok · 0ms

      Commit Rxc1 (a1c1).

  36. 36...a5Haiku8.806 tok · $0.0439 · 96157ms
    • 1. Observe0 tok · 1ms

      Halbzug 36, Schwarz am Zug. Phase: Mittelspiel. Weiss +5 Punkte. Legale Zuege: 16. Criticality: 0.10.

      • material-counter0ms
    • 2. Recall Position0 tok · 14ms

      recall: 5 similar position(s) found (limit=5).

      • nex_search14ms
    • 3. Recall Opponent0 tok · 5ms

      No pattern found for chess-sonnet-tm (tag=chess-sonnet-tm) — mandatory run documented.

      • nex_entity_search5ms
    • 4. Research0 tok · 0ms · skipped

      middlegame/endgame — research not relevant when both tools off.

    • 5. Plan4571 tok · 43322ms · claude-haiku-4-5 · $0.0228

      Phase: middlegame. Activate h8 rook to open files, push a7-a5 for passed-pawn threats, coordinate pieces to force White into passive defense within 3-5 moves. Transform the activated rook on open files and advanced a-paw…

      • llm.plan43322ms · $0.0228
      full reasoning
      Phase: middlegame. Activate h8 rook to open files, push a7-a5 for passed-pawn threats, coordinate pieces to force White into passive defense within 3-5 moves. Transform the activated rook on open files and advanced a-pawn into a favorable rook-endgame where piece coordination and passed pawns overcome the material deficit. Critical: White's consolidation threat: Rc3-d3 or e5 advance may stabilize position. Black must seize initiative now.; h8 rook is dormant; activate via h3, h2, or lateral moves to c-file to inject urgency and threaten back-rank.; a7 pawn must advance to a5 immediately to create passed-pawn tension and force White's pieces into blockade, reducing White's flexibility..
    • 6. Candidates1862 tok · 24424ms · claude-haiku-4-5 · $0.0093

      Candidates: a5 (Advances passed pawn, creates immediate threats, forces White into blockade.) | Bc5 (Most active bishop move, improves piece coordination, increases tactical pressure.) | Rg8 (Initiates rook activation se…

      • chess.js.legal_moves0ms
      • llm.candidates24423ms · $0.0093
      full reasoning
      Candidates: a5 (Advances passed pawn, creates immediate threats, forces White into blockade.) | Bc5 (Most active bishop move, improves piece coordination, increases tactical pressure.) | Rg8 (Initiates rook activation sequence from dormancy, prepares lateral mobility.)
    • 7. Verify0 tok · 1ms

      Alle 3 Kandidaten legal. cloud_eval disabled (default).

      • chess.js.legal_recheck0ms
    • 8. Reflect2373 tok · 28376ms · claude-haiku-4-5 · $0.0118

      Final pick: a5 — Passed pawn forces White's blockade commitment, frees Black's pieces for attack. White's Rooks must defend queenside, enabling rook activation and piece coordination. Critical tempo seizer when down mate…

      • llm.reflect28376ms · $0.0118
      full reasoning
      Final pick: a5 — Passed pawn forces White's blockade commitment, frees Black's pieces for attack. White's Rooks must defend queenside, enabling rook activation and piece coordination. Critical tempo seizer when down material.. Rejected: f8c5, h8g8.
    • 9. Commit0 tok · 0ms

      Commit a5 (a7a5).

  37. 37.Rc7+Sonnet946 tok · $0.0141 · 35811ms
    • 1. Observe0 tok · 0ms

      Halbzug 37, Weiss am Zug. Phase: Mittelspiel. Weiss +5 Punkte. Legale Zuege: 28. Criticality: 0.10.

      • material-counter0ms
    • 2. Recall Position0 tok · 11ms

      recall: 5 similar position(s) found (limit=5).

      • nex_search11ms
    • 3. Recall Opponent0 tok · 6ms

      No pattern found for chess-haiku-tm (tag=chess-haiku-tm) — mandatory run documented.

      • nex_entity_search6ms
    • 4. Research0 tok · 0ms · skipped

      middlegame/endgame — research not relevant when both tools off.

    • 5. Plan240 tok · 10007ms · claude-sonnet-4-6 · $0.0036

      Phase: middlegame. Penetrate to the 7th rank with check, force Black king into a mating net, convert +5 material advantage into a forced win or checkmate within 3-5 moves Drive both rooks to the 7th rank exploiting the n…

      • llm.plan10007ms · $0.0036
      full reasoning
      Phase: middlegame. Penetrate to the 7th rank with check, force Black king into a mating net, convert +5 material advantage into a forced win or checkmate within 3-5 moves Drive both rooks to the 7th rank exploiting the naked Black king on b7 — the open-file rooks heuristic (memory hit 1) confirms this is the structurally sound execution path; doubled rooks on the 7th is a classical winning mechanism. Critical: Black king on b7 has zero pawn shelter — 7th rank entry with check is immediately forcing; Memory: open file rooks heuristic validates Re7+ as the principled candidate; No opponent counter-threats of significance — Black bishop on f8 is passive, a5 pawn is irrelevant.
    • 6. Candidates551 tok · 16300ms · claude-sonnet-4-6 · $0.0082

      Candidates: Rc7+ (Rook penetrates 7th rank with check — open-file rooks heuristic confirms doubled rooks on 7th as classical winning mechanism against naked king.) | e5 (Advances passed pawn, restricts Black pieces and s…

      • chess.js.legal_moves0ms
      • llm.candidates16298ms · $0.0082
      full reasoning
      Candidates: Rc7+ (Rook penetrates 7th rank with check — open-file rooks heuristic confirms doubled rooks on 7th as classical winning mechanism against naked king.) | e5 (Advances passed pawn, restricts Black pieces and supports winning plan — trade only when ahead heuristic: simplify with material advantage.)
    • 7. Verify0 tok · 0ms

      Alle 2 Kandidaten legal. cloud_eval disabled (default).

      • chess.js.legal_recheck0ms
    • 8. Reflect155 tok · 9473ms · claude-sonnet-4-6 · $0.0023

      Final pick: Rc7+ — Rook penetrates 7th rank with check, forcing Black king to move while Re2 follows to e7 for devastating doubled rooks on 7th — the open-file rooks heuristic and king safety first principle both confirm…

      • llm.reflect9473ms · $0.0023
      full reasoning
      Final pick: Rc7+ — Rook penetrates 7th rank with check, forcing Black king to move while Re2 follows to e7 for devastating doubled rooks on 7th — the open-file rooks heuristic and king safety first principle both confirm this is immediately decisive.. Rejected: e4e5.
    • 9. Commit0 tok · 0ms

      Commit Rc7+ (c1c7).

  38. 38...Ka6Haiku16.402 tok · $0.0819 · 168077ms
    • 1. Observe0 tok · 0ms

      Halbzug 38, Schwarz am Zug. Phase: Mittelspiel. Weiss +5 Punkte. Legale Zuege: 5. Schach! Criticality: 0.55.

      • material-counter0ms
    • 2. Recall Position0 tok · 11ms

      recall: 5 similar position(s) found (limit=5).

      • nex_search11ms
    • 3. Recall Opponent0 tok · 5ms

      No pattern found for chess-sonnet-tm (tag=chess-sonnet-tm) — mandatory run documented.

      • nex_entity_search5ms
    • 4. Research0 tok · 0ms · skipped

      middlegame/endgame — research not relevant when both tools off.

    • 5. Plan1873 tok · 36288ms · claude-haiku-4-5 · $0.0093

      Phase: middlegame. Activate h8 rook via h-file or lateral c-file cross. Advance a5 to a4-a3. Force White's Rc7 into reactive moves. Inject urgency now — if White plays Rc3-d3 or e5, initiative is lost forever. Transform …

      • llm.plan36288ms · $0.0093
      full reasoning
      Phase: middlegame. Activate h8 rook via h-file or lateral c-file cross. Advance a5 to a4-a3. Force White's Rc7 into reactive moves. Inject urgency now — if White plays Rc3-d3 or e5, initiative is lost forever. Transform rook + passed pawns into coordinate attack on queenside, converting piece activity into compensation for material deficit in rook-endgame. Critical: White consolidates via Rc3-d3 (locks Black) or e5 (claims space). Window closes in 2-3 moves.; h8 rook comatose — tied to back rank. Must activate NOW.; a5 pawn is passed but isolated, lacks Luft. Advance creates tempo; forces White reaction..
    • 6. Candidates10958 tok · 94921ms · claude-haiku-4-5 · $0.0548

      Candidates: Kxc7 (Capture checking rook, eliminate White's most active piece, free rook and pawn activation.) | Kb6 (Advance king toward passed a-pawn, prepare ...a4, coordinate pieces for queenside attack.) | Ka6 (Suppo…

      • chess.js.legal_moves0ms
      • llm.candidates94921ms · $0.0548
      full reasoning
      Candidates: Kxc7 (Capture checking rook, eliminate White's most active piece, free rook and pawn activation.) | Kb6 (Advance king toward passed a-pawn, prepare ...a4, coordinate pieces for queenside attack.) | Ka6 (Support a-pawn directly, threaten ...a4 advance, force White into reactive defense mode.)
    • 7. Verify0 tok · 1ms

      Alle 3 Kandidaten legal. cloud_eval disabled (default).

      • chess.js.legal_recheck0ms
    • 8. Reflect3571 tok · 36843ms · claude-haiku-4-5 · $0.0178

      Final pick: Ka6 — Directly supports a5 pawn, threatens a4, forces White's Rc7 to react. Injects urgency now—one square closer to a4-a3 advance with king backing.. Rejected: b7c7, b7b6.

      • llm.reflect36843ms · $0.0178
    • 9. Commit0 tok · 0ms

      Commit Ka6 (b7a6).

  39. 39.Ra7+Sonnet709 tok · $0.0105 · 33890ms
    • 1. Observe0 tok · 0ms

      Halbzug 39, Weiss am Zug. Phase: Mittelspiel. Weiss +5 Punkte. Legale Zuege: 29. Criticality: 0.10.

      • material-counter0ms
    • 2. Recall Position0 tok · 6ms

      recall: 5 similar position(s) found (limit=5).

      • nex_search6ms
    • 3. Recall Opponent0 tok · 4ms

      No pattern found for chess-haiku-tm (tag=chess-haiku-tm) — mandatory run documented.

      • nex_entity_search4ms
    • 4. Research0 tok · 0ms · skipped

      middlegame/endgame — research not relevant when both tools off.

    • 5. Plan247 tok · 14088ms · claude-sonnet-4-6 · $0.0037

      Phase: middlegame. Drive both rooks to the 7th rank to create a mating net around the exposed Black king on a6; the open-file rooks heuristic confirms doubled rooks on the 7th is the classical winning mechanism. Force ki…

      • llm.plan14088ms · $0.0037
      full reasoning
      Phase: middlegame. Drive both rooks to the 7th rank to create a mating net around the exposed Black king on a6; the open-file rooks heuristic confirms doubled rooks on the 7th is the classical winning mechanism. Force king into a corner with check, then tighten the net. Convert the +5 material advantage into a forced checkmate by exploiting the naked Black king on a6 with coordinated rook pressure on the 7th rank and cutting off all escape squares. Critical: Black king on a6 has zero pawn shelter and no escape squares laterally; Open c- and e-files allow immediate rook penetration with check; Black's f8-bishop and h8-rook are passive and cannot defend the king in time; Own king on g1 is safe — no counterplay exists for Black.
    • 6. Candidates250 tok · 9411ms · claude-sonnet-4-6 · $0.0037

      Candidates: Ra7+ (Drives Black king to b6 or b5; open-file rook penetration with check exploits naked king on a6.) | Rc6+ (Check on c6 cuts off king's escape laterally; open c-file rook heuristic — immediate pressure wit…

      • chess.js.legal_moves0ms
      • llm.candidates9408ms · $0.0037
      full reasoning
      Candidates: Ra7+ (Drives Black king to b6 or b5; open-file rook penetration with check exploits naked king on a6.) | Rc6+ (Check on c6 cuts off king's escape laterally; open c-file rook heuristic — immediate pressure with tempo.) | Rxg7 (Captures pawn and doubles rooks toward 7th rank; passive f8-bishop and h8-rook cannot defend in time.)
    • 7. Verify0 tok · 1ms

      Alle 3 Kandidaten legal. cloud_eval disabled (default).

      • chess.js.legal_recheck0ms
    • 8. Reflect212 tok · 10374ms · claude-sonnet-4-6 · $0.0031

      Final pick: Ra7+ — Drives the naked king off a6 immediately with check, exploiting open-file rook penetration. King is forced to b6/b5 where Re7-e6+ or Ra6# patterns arise. King safety heuristic: our king on g1 is safe, …

      • llm.reflect10373ms · $0.0031
      full reasoning
      Final pick: Ra7+ — Drives the naked king off a6 immediately with check, exploiting open-file rook penetration. King is forced to b6/b5 where Re7-e6+ or Ra6# patterns arise. King safety heuristic: our king on g1 is safe, so we attack without restraint.. Rejected: c7c6, c7g7.
    • 9. Commit0 tok · 0ms

      Commit Ra7+ (c7a7).

  40. 40...Kxa7Haiku13.686 tok · $0.0683 · 123528ms
    • 1. Observe0 tok · 0ms

      Halbzug 40, Schwarz am Zug. Phase: Mittelspiel. Weiss +5 Punkte. Legale Zuege: 3. Schach! Criticality: 0.55.

      • material-counter0ms
    • 2. Recall Position0 tok · 12ms

      recall: 5 similar position(s) found (limit=5).

      • nex_search12ms
    • 3. Recall Opponent0 tok · 16ms

      No pattern found for chess-sonnet-tm (tag=chess-sonnet-tm) — mandatory run documented.

      • nex_entity_search16ms
    • 4. Research0 tok · 0ms · skipped

      middlegame/endgame — research not relevant when both tools off.

    • 5. Plan4079 tok · 38272ms · claude-haiku-4-5 · $0.0204

      Phase: middlegame. Escape the king check. Mobilize the dormant back-rank rook to create counterplay on open files. Advance the passed pawn to generate concrete threats before White consolidates the position. Convert mate…

      • llm.plan38272ms · $0.0204
      full reasoning
      Phase: middlegame. Escape the king check. Mobilize the dormant back-rank rook to create counterplay on open files. Advance the passed pawn to generate concrete threats before White consolidates the position. Convert material deficit into rook activity plus passed-pawn compensation, creating a complex endgame where Black's initiative and pawn threats force White into perpetual defense. Critical: White's rook dominates from the 7th rank with immediate check threat; Black's back-rank rook is comatose and must activate urgently; White's pawn advances or rook repositioning in next 2-3 moves will permanently seal Black's counterplay.
    • 6. Candidates4961 tok · 44914ms · claude-haiku-4-5 · $0.0248

      Candidates: Kxa7 (Wins checking rook, critical material for Black's counterplay on open files and rook activation.) | Kb5 (Escapes check, centralizes king toward White's pawn center, supports a-pawn advance and rook mobi…

      • chess.js.legal_moves0ms
      • llm.candidates44913ms · $0.0248
      full reasoning
      Candidates: Kxa7 (Wins checking rook, critical material for Black's counterplay on open files and rook activation.) | Kb5 (Escapes check, centralizes king toward White's pawn center, supports a-pawn advance and rook mobilization.) | Kb6 (Escapes check while maintaining king proximity to White's pieces. Keeps tactical flexibility for rook activation.)
    • 7. Verify0 tok · 1ms

      Alle 3 Kandidaten legal. cloud_eval disabled (default).

      • chess.js.legal_recheck0ms
    • 8. Reflect4646 tok · 40298ms · claude-haiku-4-5 · $0.0232

      Final pick: Kxa7 — Captures undefended rook, wins material decisively. Escapes check while activating Black's back-rank rook for immediate counterplay against White's weak king.. Rejected: a6b5, a6b6.

      • llm.reflect40298ms · $0.0232
    • 9. Commit0 tok · 0ms

      Commit Kxa7 (a6a7).

  41. 41.e5Sonnet755 tok · $0.0112 · 31734ms
    • 1. Observe0 tok · 0ms

      Halbzug 41, Weiss am Zug. Phase: Endspiel. Material gleich. Legale Zuege: 16. Criticality: 0.25.

      • material-counter0ms
    • 2. Recall Position0 tok · 16ms

      recall: 5 similar position(s) found (limit=5).

      • nex_search16ms
    • 3. Recall Opponent0 tok · 13ms

      No pattern found for chess-haiku-tm (tag=chess-haiku-tm) — mandatory run documented.

      • nex_entity_search13ms
    • 4. Research0 tok · 0ms · skipped

      middlegame/endgame — research not relevant when both tools off.

    • 5. Plan320 tok · 12934ms · claude-sonnet-4-6 · $0.0048

      Phase: endgame. Activate rook on e2 to the 7th rank (e7), threatening the Black king on a7 directly. Use the e-pawn as a passed pawn lever while coordinating king march toward center. Cut off Black king from pawns on a5 …

      • llm.plan12934ms · $0.0048
      full reasoning
      Phase: endgame. Activate rook on e2 to the 7th rank (e7), threatening the Black king on a7 directly. Use the e-pawn as a passed pawn lever while coordinating king march toward center. Cut off Black king from pawns on a5 and g7. Convert rook activity on the 7th rank into winning material gain by attacking Black's loose pawns (a5, g7, h7) while the Black king on a7 remains exposed and the Black rook on h8 is passive. Critical: Black king on a7 is exposed — Re7+ forces it to the back rank or corners; Philidor/Lucena heuristics confirm: active rook behind passed pawns is the winning mechanism here — Re7 targets Black's pawn structure directly; Black rook on h8 is completely passive and cannot defend both flanks simultaneously; Own king on g1 must begin centralizing toward e3-d4 to support pawn advances; Black's a5 pawn is isolated and vulnerable to rook attack once Re7 is established.
    • 6. Candidates242 tok · 9385ms · claude-sonnet-4-6 · $0.0036

      Candidates: Re1 (Prepares Re7 next move — active rook on 7th rank targets exposed Black king on a7 and passive rook on h8.) | e5 (Passed pawn lever advances; Philidor heuristic confirms active passed pawn behind rook is …

      • chess.js.legal_moves0ms
      • llm.candidates9385ms · $0.0036
      full reasoning
      Candidates: Re1 (Prepares Re7 next move — active rook on 7th rank targets exposed Black king on a7 and passive rook on h8.) | e5 (Passed pawn lever advances; Philidor heuristic confirms active passed pawn behind rook is the winning mechanism.) | Kg2 (King begins centralization toward e3-d4 to support pawn advances — king safety resolved, now activate.)
    • 7. Verify0 tok · 1ms

      Alle 3 Kandidaten legal. cloud_eval disabled (default).

      • chess.js.legal_recheck0ms
    • 8. Reflect193 tok · 9368ms · claude-sonnet-4-6 · $0.0029

      Final pick: e5 — Advances the passed pawn immediately, gaining space and threatening e6 next. Philidor heuristic: rook behind passed pawn is the winning mechanism. Forces Black to react while the a5 pawn stays isolated a…

      • llm.reflect9368ms · $0.0029
      full reasoning
      Final pick: e5 — Advances the passed pawn immediately, gaining space and threatening e6 next. Philidor heuristic: rook behind passed pawn is the winning mechanism. Forces Black to react while the a5 pawn stays isolated and vulnerable.. Rejected: e2e1, g1g2.
    • 9. Commit0 tok · 0ms

      Commit e5 (e4e5).

  42. 42...a4Haiku7.931 tok · $0.0395 · 89570ms
    • 1. Observe0 tok · 0ms

      Halbzug 42, Schwarz am Zug. Phase: Endspiel. Material gleich. Legale Zuege: 16. Criticality: 0.25.

      • material-counter0ms
    • 2. Recall Position0 tok · 7ms

      recall: 5 similar position(s) found (limit=5).

      • nex_search7ms
    • 3. Recall Opponent0 tok · 5ms

      No pattern found for chess-sonnet-tm (tag=chess-sonnet-tm) — mandatory run documented.

      • nex_entity_search5ms
    • 4. Research0 tok · 0ms · skipped

      middlegame/endgame — research not relevant when both tools off.

    • 5. Plan2800 tok · 30819ms · claude-haiku-4-5 · $0.0140

      Phase: endgame. Seize the initiative immediately with Rh1+ to force White's king away. Activate the dormant h8 rook via open files (h2, along the 3rd/2nd rank) to create threats against White's pawns and displace the e2 …

      • llm.plan30819ms · $0.0140
      full reasoning
      Phase: endgame. Seize the initiative immediately with Rh1+ to force White's king away. Activate the dormant h8 rook via open files (h2, along the 3rd/2nd rank) to create threats against White's pawns and displace the e2 rook. Simultaneously advance a-pawn to a4 to race against White's e5 passed pawn and create a second front. Prevent e6 by generating forcing rook + bishop tactics on both flanks. Convert the a-pawn into a genuine promotion threat that forces White into perpetual defense, achieving a draw through tempo play and perpetual checks if needed. Critical: White's e5 passed pawn will reach e6 within 2-3 moves and dominate—Black must disrupt this immediately with forcing moves; Black's h8 rook is dormant and must activate via Rh1+ or Rh2 before White's pawn advances further; White's e2 rook is the linchpin supporting the e-pawn; displacing it weakens White's attack; Black's a5 pawn is the sole counterasset—must advance to a4 before White consolidates control of the 6th rank.
    • 6. Candidates3034 tok · 32294ms · claude-haiku-4-5 · $0.0151

      Candidates: a4 (Advances passed pawn to race White's e5 threat, creating a second front that forces White into defensive calculations.) | Bd6 (Centralizes bishop to support queenside counter-attack, maintaining flexibili…

      • chess.js.legal_moves0ms
      • llm.candidates32294ms · $0.0151
      full reasoning
      Candidates: a4 (Advances passed pawn to race White's e5 threat, creating a second front that forces White into defensive calculations.) | Bd6 (Centralizes bishop to support queenside counter-attack, maintaining flexibility for rook support while controlling critical squares.) | Rg8 (Activates dormant rook away from the 8th rank, preparing to maneuver toward lower ranks for tactical opportunities.)
    • 7. Verify0 tok · 0ms

      Alle 3 Kandidaten legal. cloud_eval disabled (default).

      • chess.js.legal_recheck0ms
    • 8. Reflect2097 tok · 26437ms · claude-haiku-4-5 · $0.0104

      Final pick: a4 — Advances passed pawn creating immediate second front. Sets up Rh2 next move to displace e2 rook with tempo, forcing White to divide attention between e5 and a-pawn.. Rejected: f8d6, h8g8.

      • llm.reflect26437ms · $0.0104
    • 9. Commit0 tok · 0ms

      Commit a4 (a5a4).

  43. 43.e6Sonnet1.257 tok · $0.0187 · 39916ms
    • 1. Observe0 tok · 0ms

      Halbzug 43, Weiss am Zug. Phase: Endspiel. Material gleich. Legale Zuege: 16. Criticality: 0.25.

      • material-counter0ms
    • 2. Recall Position0 tok · 19ms

      recall: 5 similar position(s) found (limit=5).

      • nex_search19ms
    • 3. Recall Opponent0 tok · 16ms

      No pattern found for chess-haiku-tm (tag=chess-haiku-tm) — mandatory run documented.

      • nex_entity_search16ms
    • 4. Research0 tok · 0ms · skipped

      middlegame/endgame — research not relevant when both tools off.

    • 5. Plan349 tok · 13085ms · claude-sonnet-4-6 · $0.0052

      Phase: endgame. Activate rook to the 7th rank (e7), attacking Black king on a7 and loose pawns g7/h7. Use the e5 passed pawn as a lever to tie down Black's rook on h8. March White king toward center to support the passed…

      • llm.plan13085ms · $0.0052
      full reasoning
      Phase: endgame. Activate rook to the 7th rank (e7), attacking Black king on a7 and loose pawns g7/h7. Use the e5 passed pawn as a lever to tie down Black's rook on h8. March White king toward center to support the passed pawn and coordinate with rook. Convert rook activity on the 7th rank into decisive material gain by harvesting Black's kingside pawns while the passed e-pawn advances, aiming for a Lucena-type winning structure. Critical: Lucena heuristic applies: active rook behind passed pawn on 7th rank is the winning mechanism — Re7+ exposes Black king directly; Philidor heuristic warns: Black rook on h8 may activate with checks from behind if e-pawn advances carelessly — must coordinate king+rook before pushing; Black's a4-pawn is a counter-threat; White must not allow it to run while rook is on 7th; Black king on a7 is exposed but not mated — forcing it to a8 or b6 is the positional goal; Black bishop on f8 is passive but can defend g7; rook pressure must come before bishop can regroup.
    • 6. Candidates516 tok · 12876ms · claude-sonnet-4-6 · $0.0077

      Candidates: e6 (Advance passed pawn to tie down Black rook on h8, preventing it from activating with checks.) | Re4 (Rook centralizes to support e-pawn advance and guard against Black's a4 counter-threat.)

      • chess.js.legal_moves0ms
      • llm.candidates12875ms · $0.0077
    • 7. Verify0 tok · 0ms

      Alle 2 Kandidaten legal. cloud_eval disabled (default).

      • chess.js.legal_recheck0ms
    • 8. Reflect392 tok · 13906ms · claude-sonnet-4-6 · $0.0058 · err:LLM pickedUci not in verifiedCandidates (e2e7).

      Final pick: e6 — Advance passed pawn to tie down Black rook on h8, preventing it from activating with checks.. Rejected: e2e4. [LLM note: LLM pickedUci not in verifiedCandidates (e2e7).]

      • llm.reflect13906ms · $0.0058 · fail: LLM pickedUci not in verifiedCandidates (e2e7).
    • 9. Commit0 tok · 0ms

      Commit e6 (e5e6).

  44. 44...a3Haiku13.437 tok · $0.0671 · 133386ms
    • 1. Observe0 tok · 0ms

      Halbzug 44, Schwarz am Zug. Phase: Endspiel. Material gleich. Legale Zuege: 16. Criticality: 0.25.

      • material-counter0ms
    • 2. Recall Position0 tok · 12ms

      recall: 5 similar position(s) found (limit=5).

      • nex_search12ms
    • 3. Recall Opponent0 tok · 5ms

      No pattern found for chess-sonnet-tm (tag=chess-sonnet-tm) — mandatory run documented.

      • nex_entity_search5ms
    • 4. Research0 tok · 0ms · skipped

      middlegame/endgame — research not relevant when both tools off.

    • 5. Plan3712 tok · 37781ms · claude-haiku-4-5 · $0.0185

      Phase: endgame. Disrupt e7 promotion threat via Rh1+ forcing sequence; transition to Philidor defense (rook on 1st/3rd rank cutting king from e6 pawn); maintain draw through perpetual tactical tempo and a4 counter-threat…

      • llm.plan37781ms · $0.0185
      full reasoning
      Phase: endgame. Disrupt e7 promotion threat via Rh1+ forcing sequence; transition to Philidor defense (rook on 1st/3rd rank cutting king from e6 pawn); maintain draw through perpetual tactical tempo and a4 counter-threat. Hold draw by preventing e7-e8 promotion through forcing rook maneuvers and king cutoffs (Philidor principle), creating sufficient counter-threats with a4 pawn and bishop activity to achieve perpetual check or drawing position. Critical: e6 passer reaches e7 immediately if Black fails to create forcing sequence; Rh1+ is mandatory forcing move; displaces White king and enables rook to cut king from e-file; Philidor principle: rook must either cut king from promotion square or give back-rank checks; a4 pawn provides secondary counter-threat but cannot race; serves as practical drawing resource.
    • 6. Candidates7710 tok · 70784ms · claude-haiku-4-5 · $0.0385

      Candidates: Bd6 (Controls e7 diagonal, prevents e6-e7 advance while centralizing bishop. Solid defense.) | a3 (Pushes passed pawn, threatens a2-a1=Q. Forces White to choose between e7 push and a-pawn defense.) | Rg8 (Act…

      • chess.js.legal_moves0ms
      • llm.candidates70784ms · $0.0385
      full reasoning
      Candidates: Bd6 (Controls e7 diagonal, prevents e6-e7 advance while centralizing bishop. Solid defense.) | a3 (Pushes passed pawn, threatens a2-a1=Q. Forces White to choose between e7 push and a-pawn defense.) | Rg8 (Activates rook, prepares e8 defense or e-file shift. Enables coordinated Philidor-style rook structure.)
    • 7. Verify0 tok · 1ms

      Alle 3 Kandidaten legal. cloud_eval disabled (default).

      • chess.js.legal_recheck0ms
    • 8. Reflect2015 tok · 24787ms · claude-haiku-4-5 · $0.0100

      Final pick: a3 — a3 forces immediate decision: White chooses e7 (racing) or stops pawn (time-consuming). Creates forcing counter-threat supporting draw plan; Rh1+ sequence follows naturally after e7 push.. Rejected: f8d6…

      • llm.reflect24786ms · $0.0100
      full reasoning
      Final pick: a3 — a3 forces immediate decision: White chooses e7 (racing) or stops pawn (time-consuming). Creates forcing counter-threat supporting draw plan; Rh1+ sequence follows naturally after e7 push.. Rejected: f8d6, h8g8.
    • 9. Commit0 tok · 0ms

      Commit a3 (a4a3).

  45. 45.e7Sonnet1.060 tok · $0.0158 · 37149ms
    • 1. Observe0 tok · 0ms

      Halbzug 45, Weiss am Zug. Phase: Endspiel. Material gleich. Legale Zuege: 17. Criticality: 0.25.

      • material-counter0ms
    • 2. Recall Position0 tok · 16ms

      recall: 5 similar position(s) found (limit=5).

      • nex_search16ms
    • 3. Recall Opponent0 tok · 13ms

      No pattern found for chess-haiku-tm (tag=chess-haiku-tm) — mandatory run documented.

      • nex_entity_search13ms
    • 4. Research0 tok · 0ms · skipped

      middlegame/endgame — research not relevant when both tools off.

    • 5. Plan335 tok · 12401ms · claude-sonnet-4-6 · $0.0050

      Phase: endgame. Activate rook to e7 immediately, attacking the Black king on a7 and pressuring g7/h7. Use the e6 passed pawn as a permanent tie-down forcing Black's rook to stay passive on h8. March the White king toward…

      • llm.plan12401ms · $0.0050
      full reasoning
      Phase: endgame. Activate rook to e7 immediately, attacking the Black king on a7 and pressuring g7/h7. Use the e6 passed pawn as a permanent tie-down forcing Black's rook to stay passive on h8. March the White king toward d3-c4 to support the pawn advance and coordinate bridge-building toward the Lucena structure. Harvest Black's kingside pawns with the rook on the 7th rank while the e6 pawn advances to e7, then build the Lucena bridge to convert the rook-and-pawn advantage into a won position. Critical: Lucena heuristic: rook active on 7th rank behind passed pawn is the winning mechanism — Re7+ is the priority move; Philidor heuristic warns Black can draw if their rook reaches the 3rd rank to cut off the pawn — must prevent Black's rook from ever becoming active; Black's a3-pawn is a dangerous counter-threat: White king must not stray too far, and the b2 pawn needs monitoring; Black king on a7 is poorly placed but mobile — keep rook pressure to restrict its scope.
    • 6. Candidates565 tok · 15823ms · claude-sonnet-4-6 · $0.0084

      Candidates: e7 (Advances passed pawn to e7, activating Lucena mechanism; ties Black rook to h8 passively per Philidor heuristic.) | bxa3 (Eliminates dangerous a3 counter-pawn; per plan Black's a3-pawn is the primary coun…

      • chess.js.legal_moves0ms
      • llm.candidates15823ms · $0.0084
      full reasoning
      Candidates: e7 (Advances passed pawn to e7, activating Lucena mechanism; ties Black rook to h8 passively per Philidor heuristic.) | bxa3 (Eliminates dangerous a3 counter-pawn; per plan Black's a3-pawn is the primary counter-threat requiring neutralization.)
    • 7. Verify0 tok · 0ms

      Alle 2 Kandidaten legal. cloud_eval disabled (default).

      • chess.js.legal_recheck0ms
    • 8. Reflect160 tok · 8881ms · claude-sonnet-4-6 · $0.0024

      Final pick: e7 — Lucena heuristic: pawn on e7 ties Black rook permanently to h8 (Philidor defense impossible), forces Bf8 or Rxh-passivity, and creates unstoppable promotion threat. King safety is fine — no checks.. Reje…

      • llm.reflect8881ms · $0.0024
      full reasoning
      Final pick: e7 — Lucena heuristic: pawn on e7 ties Black rook permanently to h8 (Philidor defense impossible), forces Bf8 or Rxh-passivity, and creates unstoppable promotion threat. King safety is fine — no checks.. Rejected: b2a3.
    • 9. Commit0 tok · 0ms

      Commit e7 (e6e7).

  46. 46...Rg8Haiku13.864 tok · $0.0692 · 132321ms
    • 1. Observe0 tok · 0ms

      Halbzug 46, Schwarz am Zug. Phase: Endspiel. Material gleich. Legale Zuege: 12. Criticality: 0.25.

      • material-counter0ms
    • 2. Recall Position0 tok · 17ms

      recall: 5 similar position(s) found (limit=5).

      • nex_search17ms
    • 3. Recall Opponent0 tok · 6ms

      No pattern found for chess-sonnet-tm (tag=chess-sonnet-tm) — mandatory run documented.

      • nex_entity_search6ms
    • 4. Research0 tok · 0ms · skipped

      middlegame/endgame — research not relevant when both tools off.

    • 5. Plan2384 tok · 25281ms · claude-haiku-4-5 · $0.0119

      Phase: endgame. Prevent e8=Q via Rh1+ forcing move; establish Philidor rook defense (rook behind pawn on 1st rank); create perpetual check pattern through bishop and a3 counter-threats. Draw rook endgame by stopping e7 p…

      • llm.plan25281ms · $0.0119
      full reasoning
      Phase: endgame. Prevent e8=Q via Rh1+ forcing move; establish Philidor rook defense (rook behind pawn on 1st rank); create perpetual check pattern through bishop and a3 counter-threats. Draw rook endgame by stopping e7 promotion through Philidor technique and sustaining counter-play with bishop activity and a3 pawn advances, forcing perpetual check or material exchange. Critical: e8=Q is White's threat next move—mandatory disruption via Rh1+ check; After Rh1+ Kf2, establish Philidor position (rook on 1st rank behind pawn) to prevent promotion; Bishop must coordinate with rook to deliver checks from both flanks; a3 pawn provides counter-threat momentum (a4-a2 endgame race component); Perpetual check or forcing rook maneuvers essential to hold draw.
    • 6. Candidates5489 tok · 48257ms · claude-haiku-4-5 · $0.0274

      Candidates: Bxe7 (Directly removes e7 promotion threat. After Rxe7, transition to rook endgame with a3 pawn counter-play for draw.) | axb2 (Creates passed a-pawn threat (a2 push). Mutual threats force White to defend, su…

      • chess.js.legal_moves0ms
      • llm.candidates48257ms · $0.0274
      full reasoning
      Candidates: Bxe7 (Directly removes e7 promotion threat. After Rxe7, transition to rook endgame with a3 pawn counter-play for draw.) | axb2 (Creates passed a-pawn threat (a2 push). Mutual threats force White to defend, sustain drawing chances through complexity.) | Rg8 (Prepares Rxe8 to capture promoted queen. Activates rook for back-rank threats and perpetual check patterns.)
    • 7. Verify0 tok · 0ms

      Alle 3 Kandidaten legal. cloud_eval disabled (default).

      • chess.js.legal_recheck0ms
    • 8. Reflect5991 tok · 58745ms · claude-haiku-4-5 · $0.0299

      Final pick: Rg8 — Forces e8=Q Rxe8, trading rook for queen. Black retains bishop and reaches R+B+3P vs R+4P—bishop is vital for perpetual checks and coordinated defense in the resulting endgame.. Rejected: f8e7, a3b2.

      • llm.reflect58745ms · $0.0299
    • 9. Commit0 tok · 0ms

      Commit Rg8 (h8g8).

  47. 47.e8=QSonnet1.056 tok · $0.0157 · 42225ms
    • 1. Observe0 tok · 0ms

      Halbzug 47, Weiss am Zug. Phase: Endspiel. Material gleich. Legale Zuege: 25. Criticality: 0.25.

      • material-counter0ms
    • 2. Recall Position0 tok · 20ms

      recall: 5 similar position(s) found (limit=5).

      • nex_search20ms
    • 3. Recall Opponent0 tok · 10ms

      No pattern found for chess-haiku-tm (tag=chess-haiku-tm) — mandatory run documented.

      • nex_entity_search10ms
    • 4. Research0 tok · 0ms · skipped

      middlegame/endgame — research not relevant when both tools off.

    • 5. Plan384 tok · 13999ms · claude-sonnet-4-6 · $0.0057

      Phase: endgame. Activate rook to e7 to attack Black king on a7 and dominate the 7th rank, use the e7 pawn as a battering ram while marching White king toward c2-b3 to neutralize the a3 passed pawn before it queens — dual…

      • llm.plan13999ms · $0.0057
      full reasoning
      Phase: endgame. Activate rook to e7 to attack Black king on a7 and dominate the 7th rank, use the e7 pawn as a battering ram while marching White king toward c2-b3 to neutralize the a3 passed pawn before it queens — dual threats force Black into a losing defensive bind. Build the Lucena bridge: rook active on the 7th rank behind the e7 passed pawn converts the position, while the White king races to stop a3-a2 — winning by promoting e7 before Black's a-pawn can queen. Critical: Black's a3 pawn is the primary counter-threat — it must be stopped by the White king marching to b2 or the rook intercepting on a2; The Lucena heuristic demands rook activity on the 7th rank (Re7) to pin the Black king and restrict the Black rook on f8; Black rook on f8 is passive — it cannot both defend against Re7 pressure and support the a3 pawn advance; Philidor defense risk: if Black achieves rook to a8 or a1 harassing the White king, the a3 pawn becomes dangerous — White must resolve this before king walks too far; e7 pawn is already a monster — coordinating Re7 with king support completes the Lucena structure.
    • 6. Candidates506 tok · 17800ms · claude-sonnet-4-6 · $0.0076

      Candidates: e8=Q (Promotes immediately to queen; Philidor risk neutralized — a3 pawn stops mattering with Q+R.) | bxa3 (Stops a3 pawn cold — king safety first, eliminate primary counter-threat before advancing.)

      • chess.js.legal_moves0ms
      • llm.candidates17797ms · $0.0076
    • 7. Verify0 tok · 1ms

      Alle 2 Kandidaten legal. cloud_eval disabled (default).

      • chess.js.legal_recheck0ms
    • 8. Reflect166 tok · 10382ms · claude-sonnet-4-6 · $0.0025

      Final pick: e8=Q — Immediate promotion wins on the spot. Q+R vs R+B with a3 pawn is technically winning trivially — a3 stops mattering the moment the queen appears. Lucena structure complete: rook on e2 supports, queen d…

      • llm.reflect10382ms · $0.0025
      full reasoning
      Final pick: e8=Q — Immediate promotion wins on the spot. Q+R vs R+B with a3 pawn is technically winning trivially — a3 stops mattering the moment the queen appears. Lucena structure complete: rook on e2 supports, queen dominates.. Rejected: b2a3.
    • 9. Commit0 tok · 0ms

      Commit e8=Q (e7e8q).

  48. 48...Bd6Haiku13.842 tok · $0.0691 · 134403ms
    • 1. Observe0 tok · 0ms

      Halbzug 48, Schwarz am Zug. Phase: Endspiel. Weiss +8 Punkte. Legale Zuege: 13. Criticality: 0.10. AUFGABE empfohlen (Material-Floor).

      • material-counter0ms
    • 2. Recall Position0 tok · 15ms

      recall: 5 similar position(s) found (limit=5).

      • nex_search15ms
    • 3. Recall Opponent0 tok · 8ms

      No pattern found for chess-sonnet-tm (tag=chess-sonnet-tm) — mandatory run documented.

      • nex_entity_search8ms
    • 4. Research0 tok · 0ms · skipped

      middlegame/endgame — research not relevant when both tools off.

    • 5. Plan4018 tok · 38754ms · claude-haiku-4-5 · $0.0201

      Phase: endgame. Generate immediate tactical threats via rook checks (Rh1+, Rg2 attacking f2). Force White Queen into passive defense. Establish perpetual check pattern or dynamic Philidor fortress. Keep a3 pawn as shadow…

      • llm.plan38754ms · $0.0201
      full reasoning
      Phase: endgame. Generate immediate tactical threats via rook checks (Rh1+, Rg2 attacking f2). Force White Queen into passive defense. Establish perpetual check pattern or dynamic Philidor fortress. Keep a3 pawn as shadow counter-threat to occupy White's strategic attention. Disrupt White's Queen coordination through forcing checks. If perpetual checks available, lock them in. If not, deploy rook to first rank behind the passed pawn (Philidor defense) with bishop supporting. Draw via perpetual or fortress. Critical: White Queen on e8 is deep but harrassable via Rg1+/Rh1+/Rg2; a3 pawn is only concrete counter-asset; threatens to advance if White becomes entangled in checks; Rook must remain active—passive rook loses immediately; Bishop on f8 must coordinate with rook to defend and enable perpetual threats.
    • 6. Candidates3389 tok · 36274ms · claude-haiku-4-5 · $0.0169

      Candidates: axb2 (Advances passed pawn, forces White's Queen to manage a-file threat. Concrete counter-asset per plan.) | Be7 (Centralizes bishop for rook coordination. Prepares flexible defense backbone. Supports perpet…

      • chess.js.legal_moves0ms
      • llm.candidates36273ms · $0.0169
      full reasoning
      Candidates: axb2 (Advances passed pawn, forces White's Queen to manage a-file threat. Concrete counter-asset per plan.) | Be7 (Centralizes bishop for rook coordination. Prepares flexible defense backbone. Supports perpetual threat setup.) | Bd6 (Active bishop placement. Enables rook/bishop coordination for perpetual patterns. More forcing than passive retreat.)
    • 7. Verify0 tok · 0ms

      Alle 3 Kandidaten legal. cloud_eval disabled (default).

      • chess.js.legal_recheck0ms
    • 8. Reflect6435 tok · 59334ms · claude-haiku-4-5 · $0.0321

      Final pick: Bd6 — Centralizes bishop to enable Rg1+ perpetual check immediately. Maintains a3 pawn as live counter-threat. More forcing than Be7; axb2 loses pawn after Qb5+.. Rejected: a3b2, f8e7.

      • llm.reflect59334ms · $0.0321
    • 9. Commit0 tok · 0ms

      Commit Bd6 (f8d6).

  49. 49.bxa3Sonnet714 tok · $0.0106 · 35188ms
    • 1. Observe0 tok · 0ms

      Halbzug 49, Weiss am Zug. Phase: Endspiel. Weiss +8 Punkte. Legale Zuege: 36. Criticality: 0.20.

      • material-counter0ms
    • 2. Recall Position0 tok · 7ms

      recall: 5 similar position(s) found (limit=5).

      • nex_search7ms
    • 3. Recall Opponent0 tok · 8ms

      No pattern found for chess-haiku-tm (tag=chess-haiku-tm) — mandatory run documented.

      • nex_entity_search8ms
    • 4. Research0 tok · 0ms · skipped

      middlegame/endgame — research not relevant when both tools off.

    • 5. Plan297 tok · 13374ms · claude-sonnet-4-6 · $0.0044

      Phase: endgame. Activate the queen to deliver immediate threats against Black's king on a7 while simultaneously stopping the a3 passer — the Lucena heuristic applies: dominate with the major piece, march the White king t…

      • llm.plan13374ms · $0.0044
      full reasoning
      Phase: endgame. Activate the queen to deliver immediate threats against Black's king on a7 while simultaneously stopping the a3 passer — the Lucena heuristic applies: dominate with the major piece, march the White king to b2 to neutralize a3-a2 before it queens, then convert the e-pawn or g/h-pawn advantage. Win by combining queen pressure on Black's king with White king march to b2/a2 to stop the a3 passer, then promote one of White's advanced pawns while Black's material deficit is decisive. Critical: Black's a3 pawn is one step from a2 — if it queens, draw becomes possible; White king must reach b2 urgently; Black rook on g8 and bishop on d6 provide defensive resources — queen must not allow rook to become active; The Lucena heuristic confirms: major piece activity on the 7th rank combined with king centralization wins; the Philidor warning is irrelevant here as White is the attacker with queen superiority.
    • 6. Candidates243 tok · 10874ms · claude-sonnet-4-6 · $0.0036

      Candidates: Qf7+ (Drives Black king to a6/b6, activating queen on 7th rank per Lucena heuristic while gaining tempo.) | bxa3 (Eliminates the dangerous a3 passer immediately — king safety first, stop the pawn before it re…

      • chess.js.legal_moves0ms
      • llm.candidates10871ms · $0.0036
      full reasoning
      Candidates: Qf7+ (Drives Black king to a6/b6, activating queen on 7th rank per Lucena heuristic while gaining tempo.) | bxa3 (Eliminates the dangerous a3 passer immediately — king safety first, stop the pawn before it reaches a2.) | Qa4+ (Check forces Black king to move, dominating with major piece activity while keeping a3 pawn under observation.)
    • 7. Verify0 tok · 1ms

      Alle 3 Kandidaten legal. cloud_eval disabled (default).

      • chess.js.legal_recheck0ms
    • 8. Reflect174 tok · 10909ms · claude-sonnet-4-6 · $0.0026

      Final pick: bxa3 — King safety first: a3 pawn is one step from a2 queening. Eliminating it immediately removes the only drawing resource. White's queen, rook, and pawns then win easily with no counterplay.. Rejected: e8f…

      • llm.reflect10909ms · $0.0026
      full reasoning
      Final pick: bxa3 — King safety first: a3 pawn is one step from a2 queening. Eliminating it immediately removes the only drawing resource. White's queen, rook, and pawns then win easily with no counterplay.. Rejected: e8f7, e8a4.
    • 9. Commit0 tok · 0ms

      Commit bxa3 (b2a3).

  50. 50...Rxe8Haiku9.834 tok · $0.0491 · 98058ms
    • 1. Observe0 tok · 0ms

      Halbzug 50, Schwarz am Zug. Phase: Endspiel. Weiss +9 Punkte. Legale Zuege: 21. Criticality: 0.10. AUFGABE empfohlen (Material-Floor).

      • material-counter0ms
    • 2. Recall Position0 tok · 22ms

      recall: 5 similar position(s) found (limit=5).

      • nex_search22ms
    • 3. Recall Opponent0 tok · 17ms

      No pattern found for chess-sonnet-tm (tag=chess-sonnet-tm) — mandatory run documented.

      • nex_entity_search17ms
    • 4. Research0 tok · 0ms · skipped

      middlegame/endgame — research not relevant when both tools off.

    • 5. Plan2960 tok · 31382ms · claude-haiku-4-5 · $0.0148

      Phase: endgame. Disrupt White's piece coordination through forcing rook checks. Establish perpetual-check loop if White's King has limited escape squares; otherwise transition to Philidor fortress (rook on 3rd rank pivot…

      • llm.plan31382ms · $0.0148
      full reasoning
      Phase: endgame. Disrupt White's piece coordination through forcing rook checks. Establish perpetual-check loop if White's King has limited escape squares; otherwise transition to Philidor fortress (rook on 3rd rank pivoting to back rank). Bishop maintains a1 control. Goal: hold the a3 pawn long enough for draw. Force draw via perpetual checks or rook-bishop fortress defense. Prevent a3 pawn from advancing beyond a6 by sustaining back-rank pressure and promotion-square coverage. Critical: White Queen on e8 strong but not yet supporting pawn; rook checks from h1/h2 can disrupt coordination and loop perpetually if King escape limited; a3 pawn becomes unstoppable within 8–10 moves; must establish rook control before then or face fortress-endgame complexity; Bishop must never release a1; loss of promotion-square control is fatal; King on a7 can blockade pawn after forcing phase concludes; timing is critical.
    • 6. Candidates4709 tok · 41323ms · claude-haiku-4-5 · $0.0235

      Candidates: Bxh2+ (Forcing check disrupts White's King; opens h-file for subsequent rook activity; initiates pressure.) | Rxe8 (Removes White's Queen; drastically improves Black's drawing prospects in simplified rook end…

      • chess.js.legal_moves0ms
      • llm.candidates41323ms · $0.0235
      full reasoning
      Candidates: Bxh2+ (Forcing check disrupts White's King; opens h-file for subsequent rook activity; initiates pressure.) | Rxe8 (Removes White's Queen; drastically improves Black's drawing prospects in simplified rook endgame.) | Bxa3 (Eliminates dangerous passed a-pawn; prevents promotion threat; supports fortress defensive setup.)
    • 7. Verify0 tok · 0ms

      Alle 3 Kandidaten legal. cloud_eval disabled (default).

      • chess.js.legal_recheck0ms
    • 8. Reflect2165 tok · 25297ms · claude-haiku-4-5 · $0.0108

      Final pick: Rxe8 — Removes Queen, the dominant attacking piece. Simplifies to R+B vs R+pawns—a3 pawn controllable without Queen support. Black draws.. Rejected: d6h2, d6a3.

      • llm.reflect25297ms · $0.0108
    • 9. Commit0 tok · 0ms

      Commit Rxe8 (g8e8).

  51. 51.Rxe8Sonnet771 tok · $0.0115 · 32590ms
    • 1. Observe0 tok · 0ms

      Halbzug 51, Weiss am Zug. Phase: Endspiel. Material gleich. Legale Zuege: 17. Criticality: 0.15.

      • material-counter0ms
    • 2. Recall Position0 tok · 12ms

      recall: 5 similar position(s) found (limit=5).

      • nex_search12ms
    • 3. Recall Opponent0 tok · 9ms

      No pattern found for chess-haiku-tm (tag=chess-haiku-tm) — mandatory run documented.

      • nex_entity_search9ms
    • 4. Research0 tok · 0ms · skipped

      middlegame/endgame — research not relevant when both tools off.

    • 5. Plan318 tok · 13036ms · claude-sonnet-4-6 · $0.0047

      Phase: endgame. Activate the rook on e2 to cut off Black's king laterally, march White king toward d2-c2-b2 to blockade the a3 passer before it reaches a2, then advance the d- or e-pawn with rook support to force promoti…

      • llm.plan13036ms · $0.0047
      full reasoning
      Phase: endgame. Activate the rook on e2 to cut off Black's king laterally, march White king toward d2-c2-b2 to blockade the a3 passer before it reaches a2, then advance the d- or e-pawn with rook support to force promotion. Neutralize Black's a3 passer by marching the White king to b2/a2 (Lucena-derived king activation), then convert White's central pawn majority into a passed pawn that wins the endgame. Critical: Black's a3 pawn is one tempo from a2 — if it queens the game draws; White king must reach b2 urgently; Black rook on e8 is passive but can activate via e-file checks to slow White's king march; Philidor heuristic is irrelevant here (no Philidor defender role for White), but Lucena principle applies: White rook must shield the king from checks while king advances; Black bishop on d6 controls key diagonal but cannot stop both the king march and e-pawn advance simultaneously.
    • 6. Candidates248 tok · 9419ms · claude-sonnet-4-6 · $0.0037

      Candidates: Rxe8 (Eliminates Black's passive rook, removing all counterplay threats and e-file check harassment while king marches to b2.) | Kf1 (King activation toward b2 is urgent (Lucena principle): a3 passer must be …

      • chess.js.legal_moves0ms
      • llm.candidates9416ms · $0.0037
      full reasoning
      Candidates: Rxe8 (Eliminates Black's passive rook, removing all counterplay threats and e-file check harassment while king marches to b2.) | Kf1 (King activation toward b2 is urgent (Lucena principle): a3 passer must be blockaded before it reaches a2.) | d4 (Advances central pawn majority creating a second front; Black bishop on d6 cannot stop both king march and d-pawn simultaneously.)
    • 7. Verify0 tok · 0ms

      Alle 3 Kandidaten legal. cloud_eval disabled (default).

      • chess.js.legal_recheck0ms
    • 8. Reflect205 tok · 10098ms · claude-sonnet-4-6 · $0.0030

      Final pick: Rxe8 — Eliminating Black's rook removes all e-file check harassment that would slow the White king march to b2. Lucena principle: once rook is gone, king reaches b2 unimpeded and blockades a3 before it promot…

      • llm.reflect10098ms · $0.0030
      full reasoning
      Final pick: Rxe8 — Eliminating Black's rook removes all e-file check harassment that would slow the White king march to b2. Lucena principle: once rook is gone, king reaches b2 unimpeded and blockades a3 before it promotes.. Rejected: g1f1, d2d4.
    • 9. Commit0 tok · 0ms

      Commit Rxe8 (e2e8).

  52. 52...Bb4Haiku8.420 tok · $0.0420 · 90956ms
    • 1. Observe0 tok · 0ms

      Halbzug 52, Schwarz am Zug. Phase: Endspiel. Weiss +5 Punkte. Legale Zuege: 18. Criticality: 0.00.

      • material-counter0ms
    • 2. Recall Position0 tok · 11ms

      recall: 5 similar position(s) found (limit=5).

      • nex_search11ms
    • 3. Recall Opponent0 tok · 5ms

      No pattern found for chess-sonnet-tm (tag=chess-sonnet-tm) — mandatory run documented.

      • nex_entity_search5ms
    • 4. Research0 tok · 0ms · skipped

      middlegame/endgame — research not relevant when both tools off.

    • 5. Plan2247 tok · 28377ms · claude-haiku-4-5 · $0.0112

      Phase: endgame. Blockade a3 pawn with bishop on a4/b4 diagonal. Position king flexibly (b6/b7) to maintain options. Prevent White rook from infiltrating a8 or supporting pawn advance. Maintain drawing fortress or perpetu…

      • llm.plan28377ms · $0.0112
      full reasoning
      Phase: endgame. Blockade a3 pawn with bishop on a4/b4 diagonal. Position king flexibly (b6/b7) to maintain options. Prevent White rook from infiltrating a8 or supporting pawn advance. Maintain drawing fortress or perpetual defense of the a-pawn. Establish Philidor-style defensive fortress: bishop controls a-pawn promotion square and advance squares while king shadows from b-file. If White pushes a4, bishop shifts to back-rank control (a1/a8 if needed). Activate g/h pawns only after a-pawn is securely blockaded. Realistic goal: draw via indefinite defense. Critical: Opponent threats: a3-a4 pawn advance (most urgent), rook infiltration via a8 or e7-e1 line, king march to queenside to support pawn push; Own weaknesses: King on a7 is cramped; bishop stretched to cover both a-pawn blockade and back-rank tactics; g/h pawns too slow to create counterplay; Concrete tactics: bishop must immediately control a4 and b4 (prevent pawn advance); king to b6 for flexibility; rook checks must be met with bishop interposition or king shelter, not allowing rook to dominate 7th/8th rank.
    • 6. Candidates4020 tok · 37277ms · claude-haiku-4-5 · $0.0201

      Candidates: Bb4 (Blockades a4 immediately, preventing White's most dangerous pawn advance. Implements Philidor fortress: bishop controls a4/b4, ties down White's play.) | Bxa3 (Removes the advanced passed pawn; forces Wh…

      • chess.js.legal_moves0ms
      • llm.candidates37276ms · $0.0201
      full reasoning
      Candidates: Bb4 (Blockades a4 immediately, preventing White's most dangerous pawn advance. Implements Philidor fortress: bishop controls a4/b4, ties down White's play.) | Bxa3 (Removes the advanced passed pawn; forces White to work with a2-pawn. Buys time by eliminating immediate a3-a4 threat; bishop on a3 still controls promotion squares.) | Be5 (Centralizes bishop while maintaining control of key squares. Offers flexibility between defending a-pawn blockade and kingside counterplay; keeps piece active.)
    • 7. Verify0 tok · 0ms

      Alle 3 Kandidaten legal. cloud_eval disabled (default).

      • chess.js.legal_recheck0ms
    • 8. Reflect2153 tok · 25274ms · claude-haiku-4-5 · $0.0107

      Final pick: Bb4 — Blockades a4 immediately, preventing White's main threat. Bishop on b4 controls both a4 and b4 squares while remaining flexible for rook tactics.. Rejected: d6a3, d6e5.

      • llm.reflect25274ms · $0.0107
    • 9. Commit0 tok · 0ms

      Commit Bb4 (d6b4).

  53. 53.axb4Sonnet744 tok · $0.0111 · 31243ms
    • 1. Observe0 tok · 0ms

      Halbzug 53, Weiss am Zug. Phase: Endspiel. Weiss +5 Punkte. Legale Zuege: 25. Criticality: 0.00.

      • material-counter0ms
    • 2. Recall Position0 tok · 7ms

      recall: 5 similar position(s) found (limit=5).

      • nex_search7ms
    • 3. Recall Opponent0 tok · 5ms

      No pattern found for chess-haiku-tm (tag=chess-haiku-tm) — mandatory run documented.

      • nex_entity_search5ms
    • 4. Research0 tok · 0ms · skipped

      middlegame/endgame — research not relevant when both tools off.

    • 5. Plan287 tok · 11438ms · claude-sonnet-4-6 · $0.0043

      Phase: endgame. March White king to b2 immediately to blockade Black's b4-bishop and neutralize any a-pawn counterplay, then use the rook on e8 to cut off Black's king laterally while advancing the d/f pawns toward promo…

      • llm.plan11438ms · $0.0043
      full reasoning
      Phase: endgame. March White king to b2 immediately to blockade Black's b4-bishop and neutralize any a-pawn counterplay, then use the rook on e8 to cut off Black's king laterally while advancing the d/f pawns toward promotion. Convert White's +5 material advantage by building a Lucena-style bridge: king to b2 stops the bishop-supported passer, rook dominates the 8th rank cutting Black's king, then central pawns roll to promotion. Critical: Black bishop on b4 supports a pawn advance — White king must reach b2/a2 before bishop activates the a3 passer; Lucena principle: White rook on e8 already occupies the ideal cutting rank; maintain it to cage Black's king on a7; Black's king on a7 is passive but if White rook leaves e8, Black king escapes to b6 and defends actively — keep rook pressure.
    • 6. Candidates247 tok · 9388ms · claude-sonnet-4-6 · $0.0037

      Candidates: axb4 (Eliminates Black's b4-bishop immediately, removing the key defender supporting a-pawn counterplay. Lucena: trade the threat.) | Ra8+ (Cuts Black king on a-file, forcing it back. Rook dominance on 8th ra…

      • chess.js.legal_moves0ms
      • llm.candidates9387ms · $0.0037
      full reasoning
      Candidates: axb4 (Eliminates Black's b4-bishop immediately, removing the key defender supporting a-pawn counterplay. Lucena: trade the threat.) | Ra8+ (Cuts Black king on a-file, forcing it back. Rook dominance on 8th rank cages Black king per Lucena cutting principle.) | d4 (Advances central passer toward promotion. King safety already fine; pawn structure improvement rolls material advantage forward.)
    • 7. Verify0 tok · 1ms

      Alle 3 Kandidaten legal. cloud_eval disabled (default).

      • chess.js.legal_recheck0ms
    • 8. Reflect210 tok · 10399ms · claude-sonnet-4-6 · $0.0031

      Final pick: axb4 — Eliminating the b4-bishop removes Black's only active piece and sole defender of the a-pawn counterplay. With bishop gone, Black has no compensation — White's a2/d2/f2 passers roll freely to promotion …

      • llm.reflect10399ms · $0.0031
      full reasoning
      Final pick: axb4 — Eliminating the b4-bishop removes Black's only active piece and sole defender of the a-pawn counterplay. With bishop gone, Black has no compensation — White's a2/d2/f2 passers roll freely to promotion without any bishop-supported passer threat.. Rejected: e8a8, d2d4.
    • 9. Commit0 tok · 0ms

      Commit axb4 (a3b4).

  54. 54...Ka6Haiku6.102 tok · $0.0304 · 74961ms
    • 1. Observe0 tok · 0ms

      Halbzug 54, Schwarz am Zug. Phase: Endspiel. Weiss +8 Punkte. Legale Zuege: 7. Criticality: 0.00. AUFGABE empfohlen (Material-Floor).

      • material-counter0ms
    • 2. Recall Position0 tok · 11ms

      recall: 5 similar position(s) found (limit=5).

      • nex_search11ms
    • 3. Recall Opponent0 tok · 7ms

      No pattern found for chess-sonnet-tm (tag=chess-sonnet-tm) — mandatory run documented.

      • nex_entity_search7ms
    • 4. Research0 tok · 0ms · skipped

      middlegame/endgame — research not relevant when both tools off.

    • 5. Plan2723 tok · 32815ms · claude-haiku-4-5 · $0.0136

      Phase: endgame. Activate king toward a2-pawn blockade to prevent a2-a3-a4 advance; hold g/h pawns passively; exploit rook passivity or White error if available. Defend via king blockade on a3/a4 diagonal while rook stays…

      • llm.plan32815ms · $0.0136
      full reasoning
      Phase: endgame. Activate king toward a2-pawn blockade to prevent a2-a3-a4 advance; hold g/h pawns passively; exploit rook passivity or White error if available. Defend via king blockade on a3/a4 diagonal while rook stays distant; perpetual fortress is unrealistic—aim to make White work for the win and catch a mistake. Critical: a2-pawn promotion threat demands immediate king approach; White rook control of e-file enables infiltration (e7+ or e1); Black king on a7 must hurry to a3-a4 blockade zone before rook seals it.
    • 6. Candidates2096 tok · 24277ms · claude-haiku-4-5 · $0.0104

      Candidates: Ka6 (Direct king advance to a3/a4 blockade zone. Prevents a2-a3 advance; critical fortress defense.) | Kb6 (Activates king toward center while preparing blockade; maintains flexibility for counterplay attempt…

      • chess.js.legal_moves0ms
      • llm.candidates24277ms · $0.0104
      full reasoning
      Candidates: Ka6 (Direct king advance to a3/a4 blockade zone. Prevents a2-a3 advance; critical fortress defense.) | Kb6 (Activates king toward center while preparing blockade; maintains flexibility for counterplay attempts.) | Kb7 (Modest king advance toward queenside; conservative activation while preparing eventual blockade setup.)
    • 7. Verify0 tok · 0ms

      Alle 3 Kandidaten legal. cloud_eval disabled (default).

      • chess.js.legal_recheck0ms
    • 8. Reflect1283 tok · 17843ms · claude-haiku-4-5 · $0.0064

      Final pick: Ka6 — Initiates blockade of a2-pawn directly. Quickest path to a5 or a4 to stop White's a2-a3-a4 advance. Prevents losing a tempo to White's pawn push.. Rejected: a7b6, a7b7.

      • llm.reflect17843ms · $0.0064
    • 9. Commit0 tok · 0ms

      Commit Ka6 (a7a6).

  55. 55.b5+Sonnet721 tok · $0.0107 · 31341ms
    • 1. Observe0 tok · 0ms

      Halbzug 55, Weiss am Zug. Phase: Endspiel. Weiss +8 Punkte. Legale Zuege: 26. Criticality: 0.00.

      • material-counter0ms
    • 2. Recall Position0 tok · 17ms

      recall: 5 similar position(s) found (limit=5).

      • nex_search17ms
    • 3. Recall Opponent0 tok · 7ms

      No pattern found for chess-haiku-tm (tag=chess-haiku-tm) — mandatory run documented.

      • nex_entity_search7ms
    • 4. Research0 tok · 0ms · skipped

      middlegame/endgame — research not relevant when both tools off.

    • 5. Plan267 tok · 11368ms · claude-sonnet-4-6 · $0.0040

      Phase: endgame. Activate White king toward b2/a2 to neutralize any Black king counterplay, while rook on e8 keeps Black king cut off on the a-file. Then advance d and f pawns toward promotion using Lucena bridge principl…

      • llm.plan11368ms · $0.0040
      full reasoning
      Phase: endgame. Activate White king toward b2/a2 to neutralize any Black king counterplay, while rook on e8 keeps Black king cut off on the a-file. Then advance d and f pawns toward promotion using Lucena bridge principles. Convert the +8 material advantage by marching the king to support pawn advancement while the rook dominates the 8th rank, preventing Black's king from interfering with the promotion march. Critical: Black king on a6 is cut off laterally by Re8 — maintain this rook position (Lucena heuristic: rook cuts enemy king); White b4 pawn is advanced and needs king support to promote safely; Black g7/h7 pawns are irrelevant threats — Black has no counterplay with king on a6; Opposition principle: White king must approach actively, not passively wait.
    • 6. Candidates260 tok · 10412ms · claude-sonnet-4-6 · $0.0039

      Candidates: Kf1 (King activation toward b2/a2 support zone; Lucena principle: king must advance to support pawn promotion march.) | b5+ (Advances passed pawn with check, forcing Black king back; rook on e8 maintains late…

      • chess.js.legal_moves0ms
      • llm.candidates10410ms · $0.0039
      full reasoning
      Candidates: Kf1 (King activation toward b2/a2 support zone; Lucena principle: king must advance to support pawn promotion march.) | b5+ (Advances passed pawn with check, forcing Black king back; rook on e8 maintains lateral cut-off of Black king on a-file.) | Ra8+ (Drives Black king to b6/b7, disrupting its position; pawn structure heuristic: enemy king on a6 is maximally cut off after Ra8+.)
    • 7. Verify0 tok · 0ms

      Alle 3 Kandidaten legal. cloud_eval disabled (default).

      • chess.js.legal_recheck0ms
    • 8. Reflect194 tok · 9520ms · claude-sonnet-4-6 · $0.0029

      Final pick: b5+ — Advances passed pawn with check, forcing Black king to b7 or b6 — away from a5 blockade square. Lucena principle: king-cut by Re8 is maintained; b5 gains a tempo and shortens promotion distance immediat…

      • llm.reflect9520ms · $0.0029
      full reasoning
      Final pick: b5+ — Advances passed pawn with check, forcing Black king to b7 or b6 — away from a5 blockade square. Lucena principle: king-cut by Re8 is maintained; b5 gains a tempo and shortens promotion distance immediately.. Rejected: g1f1, e8a8.
    • 9. Commit0 tok · 0ms

      Commit b5+ (b4b5).

  56. 56...Kxb5Haiku15.837 tok · $0.0791 · 146992ms
    • 1. Observe0 tok · 0ms

      Halbzug 56, Schwarz am Zug. Phase: Endspiel. Weiss +8 Punkte. Legale Zuege: 5. Schach! Criticality: 0.45. AUFGABE empfohlen (Material-Floor).

      • material-counter0ms
    • 2. Recall Position0 tok · 9ms

      recall: 5 similar position(s) found (limit=5).

      • nex_search9ms
    • 3. Recall Opponent0 tok · 5ms

      No pattern found for chess-sonnet-tm (tag=chess-sonnet-tm) — mandatory run documented.

      • nex_entity_search5ms
    • 4. Research0 tok · 0ms · skipped

      middlegame/endgame — research not relevant when both tools off.

    • 5. Plan5514 tok · 51859ms · claude-haiku-4-5 · $0.0275

      Phase: endgame. Push king toward a2-pawn blockade (Kb4-Ka3/Ka4) within 2 moves; prevent a2-a3 advance and establish defensive fortress Build fortress blockade at a3/a4 to halt a-pawn promotion; passively defend g/h-pawns…

      • llm.plan51859ms · $0.0275
      full reasoning
      Phase: endgame. Push king toward a2-pawn blockade (Kb4-Ka3/Ka4) within 2 moves; prevent a2-a3 advance and establish defensive fortress Build fortress blockade at a3/a4 to halt a-pawn promotion; passively defend g/h-pawns while seeking technical draw or White miscalculation. Critical: a2-pawn advance to a3 is imminent (blocks blockade attempt); White rook penetration via Ra8, e-file, or back-rank tactics; Black king must reach blockade zone within 2 moves or a-pawn becomes unstoppable; g/h-pawns indefensible without fortress; overwhelming material disadvantage (R+5P vs 2P).
    • 6. Candidates2720 tok · 29841ms · claude-haiku-4-5 · $0.0136

      Candidates: Ka5 (Advances directly toward blockade at a4. Within 2 moves reaches critical position to stop a-pawn.) | Kxb5 (Captures advanced pawn, removes attacking material. Maintains path to Ka4 blockade within 2 move…

      • chess.js.legal_moves0ms
      • llm.candidates29841ms · $0.0136
      full reasoning
      Candidates: Ka5 (Advances directly toward blockade at a4. Within 2 moves reaches critical position to stop a-pawn.) | Kxb5 (Captures advanced pawn, removes attacking material. Maintains path to Ka4 blockade within 2 moves.) | Kb6 (Flexible approach toward Ka4/Ka5. Preserves options while king supports blockade zone containment.)
    • 7. Verify0 tok · 0ms

      Alle 3 Kandidaten legal. cloud_eval disabled (default).

      • chess.js.legal_recheck0ms
    • 8. Reflect7603 tok · 65271ms · claude-haiku-4-5 · $0.0380

      Final pick: Kxb5 — Captures b5 pawn while moving toward blockade at a4 within 2 moves. Reduces White's advancing pawns and improves Black's defensive prospects.. Rejected: a6a5, a6b6.

      • llm.reflect65271ms · $0.0380
    • 9. Commit0 tok · 0ms

      Commit Kxb5 (a6b5).

  57. 57.Rb8+Sonnet791 tok · $0.0118 · 33764ms
    • 1. Observe0 tok · 0ms

      Halbzug 57, Weiss am Zug. Phase: Endspiel. Weiss +7 Punkte. Legale Zuege: 25. Criticality: 0.00.

      • material-counter0ms
    • 2. Recall Position0 tok · 15ms

      recall: 5 similar position(s) found (limit=5).

      • nex_search15ms
    • 3. Recall Opponent0 tok · 12ms

      No pattern found for chess-haiku-tm (tag=chess-haiku-tm) — mandatory run documented.

      • nex_entity_search12ms
    • 4. Research0 tok · 0ms · skipped

      middlegame/endgame — research not relevant when both tools off.

    • 5. Plan323 tok · 13565ms · claude-sonnet-4-6 · $0.0048

      Phase: endgame. Activate White king toward center/queenside to support pawn advancement (d2, f2, a2 pawns), while rook on e8 maintains dominance of the 8th rank keeping Black king passive on b5. March the most advanced/s…

      • llm.plan13565ms · $0.0048
      full reasoning
      Phase: endgame. Activate White king toward center/queenside to support pawn advancement (d2, f2, a2 pawns), while rook on e8 maintains dominance of the 8th rank keeping Black king passive on b5. March the most advanced/supported pawn toward promotion. Convert the +7 material advantage by coordinating king and rook to escort a passed pawn to promotion — Lucena bridge principles apply once a pawn reaches the 7th rank. Critical: Lucena heuristic: rook on e8 cuts Black king laterally — maintain or improve this dominance; Black king on b5 is active; must not allow it to penetrate toward White pawns on d2/f2; King must advance from g1 toward d4/c4 to support central and queenside pawn march; Philidor reminder: if Black had a rook, we would need to consider 3rd-rank defense — here Black has no rook, so pure king+pawn coordination suffices; No immediate Black counterplay: g7/h7 pawns are blockaded by distance and Re8 controls promotion squares.
    • 6. Candidates262 tok · 10599ms · claude-sonnet-4-6 · $0.0039

      Candidates: Kf1 (King marches toward center (f1→e2→d3→c4) to escort d2/a2 pawns; Lucena principle: king active in pawn conversion.) | d4 (Advances most central passed pawn; Black king on b5 cannot intercept d4-d5-d6 quic…

      • chess.js.legal_moves0ms
      • llm.candidates10597ms · $0.0039
      full reasoning
      Candidates: Kf1 (King marches toward center (f1→e2→d3→c4) to escort d2/a2 pawns; Lucena principle: king active in pawn conversion.) | d4 (Advances most central passed pawn; Black king on b5 cannot intercept d4-d5-d6 quickly; pawn structure improvement.) | Rb8+ (Check drives Black king away from b5 activity; Lucena lateral cut maintained, king pushed further from White pawns.)
    • 7. Verify0 tok · 1ms

      Alle 3 Kandidaten legal. cloud_eval disabled (default).

      • chess.js.legal_recheck0ms
    • 8. Reflect206 tok · 9560ms · claude-sonnet-4-6 · $0.0031

      Final pick: Rb8+ — Check forces Black king away from b5, where it threatens to approach d2/f2 pawns. Lucena lateral cut principle: rook on b8 maintains dominance, king is driven to a4/a5/c4/c6 — all worse squares. Tempo …

      • llm.reflect9560ms · $0.0031
      full reasoning
      Final pick: Rb8+ — Check forces Black king away from b5, where it threatens to approach d2/f2 pawns. Lucena lateral cut principle: rook on b8 maintains dominance, king is driven to a4/a5/c4/c6 — all worse squares. Tempo gained.. Rejected: g1f1, d2d4.
    • 9. Commit0 tok · 0ms

      Commit Rb8+ (e8b8).

  58. 58...Ka4Haiku6.259 tok · $0.0312 · 73461ms
    • 1. Observe0 tok · 0ms

      Halbzug 58, Schwarz am Zug. Phase: Endspiel. Weiss +7 Punkte. Legale Zuege: 6. Schach! Criticality: 0.25.

      • material-counter0ms
    • 2. Recall Position0 tok · 14ms

      recall: 5 similar position(s) found (limit=5).

      • nex_search14ms
    • 3. Recall Opponent0 tok · 10ms

      No pattern found for chess-sonnet-tm (tag=chess-sonnet-tm) — mandatory run documented.

      • nex_entity_search10ms
    • 4. Research0 tok · 0ms · skipped

      middlegame/endgame — research not relevant when both tools off.

    • 5. Plan1637 tok · 21815ms · claude-haiku-4-5 · $0.0081

      Phase: endgame. Blockade a2-pawn by Ka4-Ka3 within next 2 moves. If a-pawn advances to a3 first, shift to Philidor/Lucena passive defense (rook 3rd-rank holding pattern). g/h pawns indefensible—fortress on a-pawn is only…

      • llm.plan21815ms · $0.0081
      full reasoning
      Phase: endgame. Blockade a2-pawn by Ka4-Ka3 within next 2 moves. If a-pawn advances to a3 first, shift to Philidor/Lucena passive defense (rook 3rd-rank holding pattern). g/h pawns indefensible—fortress on a-pawn is only survival route. Establish a3/a4 blockade within 2 moves; if achieved, Black holds for draw via technical fortress. If White plays a3 first, deploy Philidor (rook on 3rd rank vs pawn until 6th) or Lucena (back-rank check pattern) to prevent breakthrough. Critical: a2-pawn advance to a3 is imminent and will prevent blockade if moves this turn; Black king must reach a3/a4 or White queens in 2-3 moves; Rook on b8 can infiltrate via b1 (back-rank check) or lateral files—Black king blockade must be secured first; g/h pawns become liabilities once a-pawn queens; fortress is only legal draw.
    • 6. Candidates2280 tok · 24333ms · claude-haiku-4-5 · $0.0114

      Candidates: Ka4 (Direct blockade of a2-pawn before White pushes a3. Implements fortress plan.) | Ka5 (Supports blockade from alternate file. Maintains a3/a4 blockade option next move.) | Kc5 (Centralizes king toward quee…

      • chess.js.legal_moves0ms
      • llm.candidates24332ms · $0.0114
      full reasoning
      Candidates: Ka4 (Direct blockade of a2-pawn before White pushes a3. Implements fortress plan.) | Ka5 (Supports blockade from alternate file. Maintains a3/a4 blockade option next move.) | Kc5 (Centralizes king toward queenside. Explores counterplay; blockade still reachable in 2 moves.)
    • 7. Verify0 tok · 1ms

      Alle 3 Kandidaten legal. cloud_eval disabled (default).

      • chess.js.legal_recheck0ms
    • 8. Reflect2342 tok · 27280ms · claude-haiku-4-5 · $0.0117

      Final pick: Ka4 — Directly blockades a-pawn on a4 before White advances a3. Freezes promotion threat immediately, establishes fortress within critical 2-move window.. Rejected: b5a5, b5c5.

      • llm.reflect27280ms · $0.0117
    • 9. Commit0 tok · 0ms

      Commit Ka4 (b5a4).

  59. 59.Rb4+Sonnet749 tok · $0.0111 · 32299ms
    • 1. Observe0 tok · 0ms

      Halbzug 59, Weiss am Zug. Phase: Endspiel. Weiss +7 Punkte. Legale Zuege: 24. Criticality: 0.00.

      • material-counter0ms
    • 2. Recall Position0 tok · 11ms

      recall: 5 similar position(s) found (limit=5).

      • nex_search11ms
    • 3. Recall Opponent0 tok · 10ms

      No pattern found for chess-haiku-tm (tag=chess-haiku-tm) — mandatory run documented.

      • nex_entity_search10ms
    • 4. Research0 tok · 0ms · skipped

      middlegame/endgame — research not relevant when both tools off.

    • 5. Plan301 tok · 11433ms · claude-sonnet-4-6 · $0.0045

      Phase: endgame. Advance White king toward center/queenside to support pawn promotion, keep rook dominant on 8th rank cutting Black king laterally, march the d2 or a2 pawn toward queening square Convert +7 material advant…

      • llm.plan11433ms · $0.0045
      full reasoning
      Phase: endgame. Advance White king toward center/queenside to support pawn promotion, keep rook dominant on 8th rank cutting Black king laterally, march the d2 or a2 pawn toward queening square Convert +7 material advantage by coordinating king and rook to escort a passed pawn to promotion using Lucena bridge principles once pawn reaches 7th rank. Critical: Black king on a4 is dangerously close to White pawns on a2 and d2 — must not allow capture; Rook on b8 dominates 8th rank, cutting Black king from returning to back ranks — maintain this; Lucena heuristic: once a pawn reaches 7th rank with rook support, build the bridge to shelter White king from check; Philidor heuristic: irrelevant here as White is the winning side with material advantage — focus on active rook use; Black king on a4 threatens a2 pawn immediately — king activation toward a2 defense or rook interposition is critical.
    • 6. Candidates254 tok · 10450ms · claude-sonnet-4-6 · $0.0038

      Candidates: Rb4+ (Checks Black king, drives it away from a2 pawn. Lucena principle: rook must be active, not passive. Defends a2 while gaining tempo.) | d4 (Advances passed pawn toward promotion. King safety is fine; now…

      • chess.js.legal_moves0ms
      • llm.candidates10449ms · $0.0038
      full reasoning
      Candidates: Rb4+ (Checks Black king, drives it away from a2 pawn. Lucena principle: rook must be active, not passive. Defends a2 while gaining tempo.) | d4 (Advances passed pawn toward promotion. King safety is fine; now march the pawn. Cuts Black king's lateral options further.) | Ra8+ (Forces Black king to move, maintaining rook dominance on 8th rank per plan. Cuts king from back rank.)
    • 7. Verify0 tok · 0ms

      Alle 3 Kandidaten legal. cloud_eval disabled (default).

      • chess.js.legal_recheck0ms
    • 8. Reflect194 tok · 10384ms · claude-sonnet-4-6 · $0.0029

      Final pick: Rb4+ — Lucena active rook principle: Rb4+ checks Black king off a2, defends our pawn, and forces king away — gaining tempo while solving the immediate threat of Kxa2 in one move.. Rejected: d2d4, b8a8.

      • llm.reflect10384ms · $0.0029
    • 9. Commit0 tok · 0ms

      Commit Rb4+ (b8b4).

  60. 60...Ka3Haiku17.193 tok · $0.0859 · 177022ms
    • 1. Observe0 tok · 0ms

      Halbzug 60, Schwarz am Zug. Phase: Endspiel. Weiss +7 Punkte. Legale Zuege: 3. Schach! Criticality: 0.45.

      • material-counter0ms
    • 2. Recall Position0 tok · 15ms

      recall: 5 similar position(s) found (limit=5).

      • nex_search15ms
    • 3. Recall Opponent0 tok · 5ms

      No pattern found for chess-sonnet-tm (tag=chess-sonnet-tm) — mandatory run documented.

      • nex_entity_search5ms
    • 4. Research0 tok · 0ms · skipped

      middlegame/endgame — research not relevant when both tools off.

    • 5. Plan3807 tok · 41274ms · claude-haiku-4-5 · $0.0190

      Phase: endgame. Blockade a2-pawn at a3 in next 2 moves to establish fortress. If a3-advance occurs first, transition to Philidor defense (rook 3rd rank) then Lucena (back-rank checks) as pawn advances. Technical fortress…

      • llm.plan41274ms · $0.0190
      full reasoning
      Phase: endgame. Blockade a2-pawn at a3 in next 2 moves to establish fortress. If a3-advance occurs first, transition to Philidor defense (rook 3rd rank) then Lucena (back-rank checks) as pawn advances. Technical fortress draw via a-pawn blockade and Philidor-Lucena rook patterns. Exploit passive rook positioning to hold indefinitely against White's material advantage. Critical: a2-pawn must be blockaded at a3 within next moves or fortress collapses; if White plays a3 first, Philidor pattern (rook on 3rd rank vs pawn) becomes essential to prevent breakthrough; rook must transition to 1st rank checks (Lucena building-bridge) once pawn reaches a6.
    • 6. Candidates7082 tok · 73310ms · claude-haiku-4-5 · $0.0354

      Candidates: Ka3 (Blockades critical a2-pawn at a3, establishing fortress immediately per plan. Prevents breakthrough.) | Ka5 (Advances King actively, forces White's choice. Can blockade at a3 next move if needed.) | Kxb4…

      • chess.js.legal_moves0ms
      • llm.candidates73310ms · $0.0354
      full reasoning
      Candidates: Ka3 (Blockades critical a2-pawn at a3, establishing fortress immediately per plan. Prevents breakthrough.) | Ka5 (Advances King actively, forces White's choice. Can blockade at a3 next move if needed.) | Kxb4 (Removes attacking Rook but allows White King to capture g7/h7 pawns. Loses endgame.)
    • 7. Verify0 tok · 0ms

      Alle 3 Kandidaten legal. cloud_eval disabled (default).

      • chess.js.legal_recheck0ms
    • 8. Reflect6304 tok · 62406ms · claude-haiku-4-5 · $0.0315

      Final pick: Ka3 — Immediately blockades a2-pawn, forcing Ra4+ which either allows Kxa2 (removing threat) or repositioning to re-blockade. Establishes fortress in one move.. Rejected: a4a5, a4b4.

      • llm.reflect62406ms · $0.0315
    • 9. Commit0 tok · 0ms

      Commit Ka3 (a4a3).

  61. 61.Rb3+Sonnet717 tok · $0.0106 · 34303ms
    • 1. Observe0 tok · 0ms

      Halbzug 61, Weiss am Zug. Phase: Endspiel. Weiss +7 Punkte. Legale Zuege: 23. Criticality: 0.00.

      • material-counter0ms
    • 2. Recall Position0 tok · 8ms

      recall: 5 similar position(s) found (limit=5).

      • nex_search8ms
    • 3. Recall Opponent0 tok · 6ms

      No pattern found for chess-haiku-tm (tag=chess-haiku-tm) — mandatory run documented.

      • nex_entity_search6ms
    • 4. Research0 tok · 0ms · skipped

      middlegame/endgame — research not relevant when both tools off.

    • 5. Plan292 tok · 13017ms · claude-sonnet-4-6 · $0.0043

      Phase: endgame. Activate White king toward queenside to support a2 or d2 pawn advance, keep rook cutting Black king laterally, and march a passed pawn to promotion within 4-5 moves. Convert the +7 material advantage by c…

      • llm.plan13017ms · $0.0043
      full reasoning
      Phase: endgame. Activate White king toward queenside to support a2 or d2 pawn advance, keep rook cutting Black king laterally, and march a passed pawn to promotion within 4-5 moves. Convert the +7 material advantage by coordinating king and rook to escort a passed pawn to queening, using Lucena bridge principles once the pawn reaches the 7th rank. Critical: Black king on a3 is adjacent to White pawns a2 and d2 — king must advance to drive Black king back and protect pawns; Rook on b4 currently does NOT cut Black king laterally — repositioning to b-file or 8th rank needed to contain Black king; Memory heuristics: Lucena bridge (rook + pawn vs rook win method) and Opposition principle both confirm king activation is the priority before pawn advance; Black g7/h7 pawns are irrelevant threats for now — White's material edge wins if pawns are protected and king advances.
    • 6. Candidates238 tok · 9373ms · claude-sonnet-4-6 · $0.0035

      Candidates: Rb3+ (Checks Black king on a3, drives it back and protects a2/d2 pawns. Lucena: rook cuts laterally.) | Ra4+ (Check forces Black king away from a3, severs its grip on White pawns. Opposition principle: king g…

      • chess.js.legal_moves0ms
      • llm.candidates9372ms · $0.0035
      full reasoning
      Candidates: Rb3+ (Checks Black king on a3, drives it back and protects a2/d2 pawns. Lucena: rook cuts laterally.) | Ra4+ (Check forces Black king away from a3, severs its grip on White pawns. Opposition principle: king gains space.) | d4 (Advances passed d-pawn two squares toward promotion; king safety intact on g1.)
    • 7. Verify0 tok · 1ms

      Alle 3 Kandidaten legal. cloud_eval disabled (default).

      • chess.js.legal_recheck0ms
    • 8. Reflect187 tok · 11885ms · claude-sonnet-4-6 · $0.0028

      Final pick: Rb3+ — Check drives Black king off a3, immediately protecting a2 and d2 pawns. Rook on b3 cuts the 3rd rank laterally — Lucena principle: rook behind pawn, king advances next.. Rejected: b4a4, d2d4.

      • llm.reflect11885ms · $0.0028
    • 9. Commit0 tok · 0ms

      Commit Rb3+ (b4b3).

  62. 62...Kxa2Haiku15.013 tok · $0.0750 · 140402ms
    • 1. Observe0 tok · 0ms

      Halbzug 62, Schwarz am Zug. Phase: Endspiel. Weiss +7 Punkte. Legale Zuege: 2. Schach! Criticality: 0.45.

      • material-counter0ms
    • 2. Recall Position0 tok · 13ms

      recall: 5 similar position(s) found (limit=5).

      • nex_search13ms
    • 3. Recall Opponent0 tok · 6ms

      No pattern found for chess-sonnet-tm (tag=chess-sonnet-tm) — mandatory run documented.

      • nex_entity_search6ms
    • 4. Research0 tok · 0ms · skipped

      middlegame/endgame — research not relevant when both tools off.

    • 5. Plan2891 tok · 28297ms · claude-haiku-4-5 · $0.0144

      Phase: endgame. Blockade the a2-pawn at a3 within 2 moves to establish a fortress position. Prevent pawn breakthrough while exploiting White's awkwardly placed rook. Transition to Philidor pattern (rook 3rd rank control)…

      • llm.plan28297ms · $0.0144
      full reasoning
      Phase: endgame. Blockade the a2-pawn at a3 within 2 moves to establish a fortress position. Prevent pawn breakthrough while exploiting White's awkwardly placed rook. Transition to Philidor pattern (rook 3rd rank control) if a3-advance occurs. Hold a fortress draw despite material deficit via a2-pawn blockade and precise Philidor-Lucena rook defensive geometry. Critical: a2-pawn breakthrough is the only winning threat — must blockade immediately; White rook on b3 has limited scope — maintain king-rook coordination to restrict it further; Philidor position (rook 3rd rank until pawn reaches 6th) then Lucena (back-rank checks) are the technical foundation for this draw.
    • 6. Candidates4168 tok · 39250ms · claude-haiku-4-5 · $0.0208

      Candidates: Kxa2 (Captures a2 pawn, eliminates breakthrough threat, solidifies fortress foundation immediately.) | Ka4 (Moves king away from White rook, maintains activity; allows a3 advance next move.)

      • chess.js.legal_moves0ms
      • llm.candidates39250ms · $0.0208
    • 7. Verify0 tok · 0ms

      Alle 2 Kandidaten legal. cloud_eval disabled (default).

      • chess.js.legal_recheck0ms
    • 8. Reflect7954 tok · 72822ms · claude-haiku-4-5 · $0.0397

      Final pick: Kxa2 — Capture eliminates White's only winning threat immediately. Kxa2 prevents Rc3+ dislodging a blockade, secures the fortress foundation.. Rejected: a3a4.

      • llm.reflect72822ms · $0.0397
    • 9. Commit0 tok · 0ms

      Commit Kxa2 (a3a2).

  63. 63.Ra3+Sonnet567 tok · $0.0084 · 33436ms
    • 1. Observe0 tok · 0ms

      Halbzug 63, Weiss am Zug. Phase: Endspiel. Weiss +6 Punkte. Legale Zuege: 23. Criticality: 0.00.

      • material-counter0ms
    • 2. Recall Position0 tok · 21ms

      recall: 5 similar position(s) found (limit=5).

      • nex_search21ms
    • 3. Recall Opponent0 tok · 9ms

      No pattern found for chess-haiku-tm (tag=chess-haiku-tm) — mandatory run documented.

      • nex_entity_search9ms
    • 4. Research0 tok · 0ms · skipped

      middlegame/endgame — research not relevant when both tools off.

    • 5. Plan313 tok · 12427ms · claude-sonnet-4-6 · $0.0047

      Phase: endgame. Activate White king toward d2/c2 to shield pawns from Black king on a2, while repositioning rook to cut Black king or support pawn advance. Target: escort d2 or f2 pawn to promotion within 5 moves. Conver…

      • llm.plan12427ms · $0.0047
      full reasoning
      Phase: endgame. Activate White king toward d2/c2 to shield pawns from Black king on a2, while repositioning rook to cut Black king or support pawn advance. Target: escort d2 or f2 pawn to promotion within 5 moves. Convert +6 material advantage by coordinating king and rook to escort a passed pawn to queening — Lucena bridge principles apply once pawn reaches 7th rank. Critical: Black king on a2 is adjacent to White pawns d2 and f2 — immediate threat to capture one; Rook on b3 must either cut Black king laterally (Rb3-a3 check or rank cut) or support pawn push; Lucena bridge: once d2 reaches d7 with king in front, rook builds bridge to shelter king from Black rook checks; Philidor heuristic: Black has no rook so classical Philidor defense is irrelevant — pure K+R vs K+pawns scenario; Opposition heuristic: White king must gain opposition against Black king to drive it away from promotion square.
    • 6. Candidates254 tok · 9884ms · claude-sonnet-4-6 · $0.0038

      Candidates: Ra3+ (Cuts Black king on a-file immediately; opposition heuristic: forces Ka2-b1/b2, separating king from d2 pawn.) | Rb2+ (Check drives Black king away from d2/f2 pawns; Lucena bridge prep — rook repositions…

      • chess.js.legal_moves0ms
      • llm.candidates9883ms · $0.0038
      full reasoning
      Candidates: Ra3+ (Cuts Black king on a-file immediately; opposition heuristic: forces Ka2-b1/b2, separating king from d2 pawn.) | Rb2+ (Check drives Black king away from d2/f2 pawns; Lucena bridge prep — rook repositions to support pawn advance.) | d4 (Advances passed pawn with tempo; king safety first satisfied — White king on g1 is safe while pawn races forward.)
    • 7. Verify0 tok · 1ms

      Alle 3 Kandidaten legal. cloud_eval disabled (default).

      • chess.js.legal_recheck0ms
    • 8. Reflect0 tok · 11079ms · claude-sonnet-4-6

      Final pick: Ra3+ — Cuts Black king on a-file immediately (opposition heuristic: Ka2 forced to b1/b2, separating it from d2 and f2 pawns). Lucena bridge: rook on a3 can then slide to a7/a8 to shield king once pawn advance…

      • llm.reflect11079ms
      full reasoning
      Final pick: Ra3+ — Cuts Black king on a-file immediately (opposition heuristic: Ka2 forced to b1/b2, separating it from d2 and f2 pawns). Lucena bridge: rook on a3 can then slide to a7/a8 to shield king once pawn advances.. Rejected: b3b2, d2d4.
    • 9. Commit0 tok · 0ms

      Commit Ra3+ (b3a3).

  64. 64...Kxa3Haiku8.565 tok · $0.0427 · 103180ms
    • 1. Observe0 tok · 0ms

      Halbzug 64, Schwarz am Zug. Phase: Endspiel. Weiss +6 Punkte. Legale Zuege: 3. Schach! Criticality: 0.45.

      • material-counter0ms
    • 2. Recall Position0 tok · 20ms

      recall: 5 similar position(s) found (limit=5).

      • nex_search20ms
    • 3. Recall Opponent0 tok · 6ms

      No pattern found for chess-sonnet-tm (tag=chess-sonnet-tm) — mandatory run documented.

      • nex_entity_search6ms
    • 4. Research0 tok · 0ms · skipped

      middlegame/endgame — research not relevant when both tools off.

    • 5. Plan2371 tok · 35860ms · claude-haiku-4-5 · $0.0118

      Phase: endgame. Activate Black's king toward White's center pawns (d2, f2) within 3–5 moves to create blockade threats. Target d-file or c-file entry points. Escape passive confinement on the a-file. Force White's rook i…

      • llm.plan35860ms · $0.0118
      full reasoning
      Phase: endgame. Activate Black's king toward White's center pawns (d2, f2) within 3–5 moves to create blockade threats. Target d-file or c-file entry points. Escape passive confinement on the a-file. Force White's rook into defensive posture and create practical drawing chances through king activity and pawn-line disruption. Transform from a passive, trapped king position into an active fortress around White's advanced pawns (esp. d2), leveraging the rook's current limitation on a3 to slip the Black king toward the center. Critical: White's d-pawn is the acute threat — Black must either blockade it or create perpetual tactical pressure against it; Black's king on a2 is currently restricted by Ra3 but paradoxically semi-sheltered; next moves must escape toward c3/d3 via Kb1–Kb2 or similar; White's rook on a3 limits its own pawn-support tempo; Black must exploit this window before Kg1 advances or rook repositions; White's king (g1) is remote — critical window exists before it reaches d3 or e3 to support the center pawns; Black's g7 and h7 pawns are currently inert; win or draw depends entirely on king-blockade geometry around White's passed d-pawn.
    • 6. Candidates5195 tok · 47798ms · claude-haiku-4-5 · $0.0259

      Candidates: Kxa3 (Captures rook, wins decisive material. King blockades d2 in 2-3 moves via b3-b2.) | Kb2 (Activates king toward d2 blockade, escapes a-file passivity. Fits endgame plan directly.) | Kb1 (Retreats king; l…

      • chess.js.legal_moves0ms
      • llm.candidates47797ms · $0.0259
      full reasoning
      Candidates: Kxa3 (Captures rook, wins decisive material. King blockades d2 in 2-3 moves via b3-b2.) | Kb2 (Activates king toward d2 blockade, escapes a-file passivity. Fits endgame plan directly.) | Kb1 (Retreats king; less forcing than b2. Hedges against Ra2+ but slower blockade access.)
    • 7. Verify0 tok · 0ms

      Alle 3 Kandidaten legal. cloud_eval disabled (default).

      • chess.js.legal_recheck0ms
    • 8. Reflect999 tok · 19481ms · claude-haiku-4-5 · $0.0050

      Final pick: Kxa3 — Wins rook cleanly; Black secures decisive material advantage and converts to victory or fortress draw within 10 moves.. Rejected: a2b2, a2b1.

      • llm.reflect19481ms · $0.0050
    • 9. Commit0 tok · 0ms

      Commit Kxa3 (a2a3).

  65. 65.Kf1Sonnet807 tok · $0.0120 · 31878ms
    • 1. Observe0 tok · 1ms

      Halbzug 65, Weiss am Zug. Phase: Endspiel. Weiss +1 Punkte. Legale Zuege: 9. Criticality: 0.15.

      • material-counter0ms
    • 2. Recall Position0 tok · 20ms

      recall: 5 similar position(s) found (limit=5).

      • nex_search20ms
    • 3. Recall Opponent0 tok · 7ms

      No pattern found for chess-haiku-tm (tag=chess-haiku-tm) — mandatory run documented.

      • nex_entity_search7ms
    • 4. Research0 tok · 0ms · skipped

      middlegame/endgame — research not relevant when both tools off.

    • 5. Plan313 tok · 12424ms · claude-sonnet-4-6 · $0.0047

      Phase: endgame. Activate White king from g1 toward the center/d-file to shield d2 and f2 pawns from Black king on a3, then escort the most advanced pawn to promotion. Black king is dangerously close to White pawns — king…

      • llm.plan12424ms · $0.0047
      full reasoning
      Phase: endgame. Activate White king from g1 toward the center/d-file to shield d2 and f2 pawns from Black king on a3, then escort the most advanced pawn to promotion. Black king is dangerously close to White pawns — king must interpose before a pawn falls. March the White king to d3 or e3 to cut off the Black king from the d2/f2 pawns, then push one pawn to promotion while the king escorts it — Lucena bridge principles apply once pawn reaches 7th rank. Critical: Black king on a3 threatens to march to b2/c2 and capture d2 or f2 — immediate king activation required; Philidor/Lucena heuristics: no rook present, so king must serve as the escort — opposition control near d-file is decisive; White has three passed pawns (d2, f2, h2) — Black has g7/h7 counterplay but they are far back; converting one White pawn before Black passers become dangerous is the strategic race.
    • 6. Candidates253 tok · 9881ms · claude-sonnet-4-6 · $0.0038

      Candidates: Kf1 (King activation toward center — Lucena/escort principle: king must march to d3 to shield d2/f2 from Black king on a3.) | d4 (Advance most central passer; gains space and outpaces Black king march — Phili…

      • chess.js.legal_moves0ms
      • llm.candidates9881ms · $0.0038
      full reasoning
      Candidates: Kf1 (King activation toward center — Lucena/escort principle: king must march to d3 to shield d2/f2 from Black king on a3.) | d4 (Advance most central passer; gains space and outpaces Black king march — Philidor race heuristic favors pushing passed pawns.) | f4 (Second passer advances, creating dual promotion threats; Black king on a3 cannot cover both f-file and d-file simultaneously.)
    • 7. Verify0 tok · 0ms

      Alle 3 Kandidaten legal. cloud_eval disabled (default).

      • chess.js.legal_recheck0ms
    • 8. Reflect241 tok · 9535ms · claude-sonnet-4-6 · $0.0036

      Final pick: Kf1 — King must activate immediately toward d3 to interpose between Black king (a3) and the d2/f2 pawns. Lucena escort principle: without king escort, Black king reaches b2/c2 and captures a pawn before any p…

      • llm.reflect9535ms · $0.0036
      full reasoning
      Final pick: Kf1 — King must activate immediately toward d3 to interpose between Black king (a3) and the d2/f2 pawns. Lucena escort principle: without king escort, Black king reaches b2/c2 and captures a pawn before any promotion. Pawn moves gain space but abandon the king on g1, letting Black king run to c2 unchallenged.. Rejected: d2d4, f2f4.
    • 9. Commit0 tok · 0ms

      Commit Kf1 (g1f1).

  66. 66...Kb4Haiku12.253 tok · $0.0612 · 119444ms
    • 1. Observe0 tok · 0ms

      Halbzug 66, Schwarz am Zug. Phase: Endspiel. Weiss +1 Punkte. Legale Zuege: 9. Criticality: 0.15.

      • material-counter0ms
    • 2. Recall Position0 tok · 20ms

      recall: 5 similar position(s) found (limit=5).

      • nex_search20ms
    • 3. Recall Opponent0 tok · 14ms

      No pattern found for chess-sonnet-tm (tag=chess-sonnet-tm) — mandatory run documented.

      • nex_entity_search14ms
    • 4. Research0 tok · 0ms · skipped

      middlegame/endgame — research not relevant when both tools off.

    • 5. Plan1713 tok · 20882ms · claude-haiku-4-5 · $0.0085

      Phase: endgame. Activate Black's king from a3 toward d-file (blockade or harass d2 pawn within 3 moves). Simultaneously prepare g7→g5 push to generate kingside counterplay before White's king can defend both flanks. Tran…

      • llm.plan20882ms · $0.0085
      full reasoning
      Phase: endgame. Activate Black's king from a3 toward d-file (blockade or harass d2 pawn within 3 moves). Simultaneously prepare g7→g5 push to generate kingside counterplay before White's king can defend both flanks. Transform passive, confined king position into active fortress around d2 pawn via Kb4-Kc3, forcing White's king into defensive duty while Black races kingside pawns. Critical: d2 pawn advance beyond d3 is catastrophic; must blockade or attack it immediately; White's king on f1 is too far right to defend both d2 and kingside; exploit this lag; Opposition and zugzwang in K+P endgames are lethal — avoid moves that gift White the tempo.
    • 6. Candidates6194 tok · 56678ms · claude-haiku-4-5 · $0.0309

      Candidates: Kb4 (Activate king toward d-file to blockade d2 pawn within 3 moves (Kc3 next). Urgent per plan.) | g5 (Generate immediate kingside counterplay before White's distant f1 king can defend both flanks.) | Kb3 (A…

      • chess.js.legal_moves0ms
      • llm.candidates56678ms · $0.0309
      full reasoning
      Candidates: Kb4 (Activate king toward d-file to blockade d2 pawn within 3 moves (Kc3 next). Urgent per plan.) | g5 (Generate immediate kingside counterplay before White's distant f1 king can defend both flanks.) | Kb3 (Alternative centralized path toward d-file to harass d2 pawn blockade. Similar goal to Kb4.)
    • 7. Verify0 tok · 1ms

      Alle 3 Kandidaten legal. cloud_eval disabled (default).

      • chess.js.legal_recheck0ms
    • 8. Reflect4346 tok · 41834ms · claude-haiku-4-5 · $0.0217

      Final pick: Kb4 — Directly activates king toward d-file blockade (Kc3 next move). Forcing White to respond. Urgently stops d2 pawn advance before d3. Maximum pressure.. Rejected: g7g5, a3b3.

      • llm.reflect41834ms · $0.0217
    • 9. Commit0 tok · 0ms

      Commit Kb4 (a3b4).

  67. 67.Ke2Sonnet804 tok · $0.0120 · 41202ms
    • 1. Observe0 tok · 0ms

      Halbzug 67, Weiss am Zug. Phase: Endspiel. Weiss +1 Punkte. Legale Zuege: 10. Criticality: 0.15.

      • material-counter0ms
    • 2. Recall Position0 tok · 19ms

      recall: 5 similar position(s) found (limit=5).

      • nex_search19ms
    • 3. Recall Opponent0 tok · 8ms

      No pattern found for chess-haiku-tm (tag=chess-haiku-tm) — mandatory run documented.

      • nex_entity_search8ms
    • 4. Research0 tok · 0ms · skipped

      middlegame/endgame — research not relevant when both tools off.

    • 5. Plan360 tok · 19806ms · claude-sonnet-4-6 · $0.0054

      Phase: endgame. March White king toward d3/e3 to shield the d2 and f2 pawns from the Black king on b4, then escort the most advanced pawn (d2 or f2) to promotion using king escort principles. Activate White king centrall…

      • llm.plan19806ms · $0.0054
      full reasoning
      Phase: endgame. March White king toward d3/e3 to shield the d2 and f2 pawns from the Black king on b4, then escort the most advanced pawn (d2 or f2) to promotion using king escort principles. Activate White king centrally to cut off Black king, then promote one pawn while the king escorts it — applying opposition principles to outmaneuver the Black king and reach a winning K+Q vs K endgame. Critical: Black king on b4 threatens c3/c2, directly attacking d2 and f2 pawns — immediate king interposition required; Memory hit [ENDGAME opposition]: White must seize opposition to push Black king back and escort a pawn safely; Memory hit [ENDGAME lucena rook]: Lucena bridge principles apply once a pawn nears promotion — though rook absent, king escort fulfills the same shielding role; White has three pawns (d2, f2, h2) vs Black's two (g7, h7) — material edge, but pawns are far back and king must act before Black king eats them; 10 legal moves available — king activation via Ke2 or Ke1-d1 toward the queenside pawn is highest priority.
    • 6. Candidates241 tok · 10974ms · claude-sonnet-4-6 · $0.0036

      Candidates: Ke2 (King centralization toward d2/f2 pawns; seizes opposition principle — cuts off Black king on b4 from approaching d2.) | Ke1 (King moves toward queenside via d1, preparing to escort d2 pawn; king safety f…

      • chess.js.legal_moves0ms
      • llm.candidates10974ms · $0.0036
      full reasoning
      Candidates: Ke2 (King centralization toward d2/f2 pawns; seizes opposition principle — cuts off Black king on b4 from approaching d2.) | Ke1 (King moves toward queenside via d1, preparing to escort d2 pawn; king safety first before pawn advances.) | d4 (Advances most-threatened pawn two squares; gains space but king must follow immediately per Lucena escort principle.)
    • 7. Verify0 tok · 0ms

      Alle 3 Kandidaten legal. cloud_eval disabled (default).

      • chess.js.legal_recheck0ms
    • 8. Reflect203 tok · 10383ms · claude-sonnet-4-6 · $0.0030

      Final pick: Ke2 — Ke2 centralizes the king immediately between d2 and f2 pawns, seizing opposition against Black king on b4 — cuts off approach to c3/d2 while escorting both pawns. King safety first before advancing pawn…

      • llm.reflect10383ms · $0.0030
      full reasoning
      Final pick: Ke2 — Ke2 centralizes the king immediately between d2 and f2 pawns, seizing opposition against Black king on b4 — cuts off approach to c3/d2 while escorting both pawns. King safety first before advancing pawns.. Rejected: f1e1, d2d4.
    • 9. Commit0 tok · 0ms

      Commit Ke2 (f1e2).

  68. 68...Kc4Haiku9.627 tok · $0.0480 · 95358ms
    • 1. Observe0 tok · 0ms

      Halbzug 68, Schwarz am Zug. Phase: Endspiel. Weiss +1 Punkte. Legale Zuege: 11. Criticality: 0.15.

      • material-counter0ms
    • 2. Recall Position0 tok · 18ms

      recall: 5 similar position(s) found (limit=5).

      • nex_search18ms
    • 3. Recall Opponent0 tok · 7ms

      No pattern found for chess-sonnet-tm (tag=chess-sonnet-tm) — mandatory run documented.

      • nex_entity_search7ms
    • 4. Research0 tok · 0ms · skipped

      middlegame/endgame — research not relevant when both tools off.

    • 5. Plan5197 tok · 48253ms · claude-haiku-4-5 · $0.0259

      Phase: endgame. Activate Black's king toward the center to directly threaten White's advanced d-pawn, force White into a critical decision (advance d3 or defend with king), and simultaneously threaten kingside pawn expan…

      • llm.plan48253ms · $0.0259
      full reasoning
      Phase: endgame. Activate Black's king toward the center to directly threaten White's advanced d-pawn, force White into a critical decision (advance d3 or defend with king), and simultaneously threaten kingside pawn expansion to generate dynamic counterplay. Establish Black's king as a permanent blockader of White's d-pawn, forcing White's king into perpetual kingside defense while Black's g/h pawns create passed-pawn threats. Critical: White's d-pawn threatens to escape beyond d4. If unchecked past d3, Black loses immediately. Blockade via king activation is non-negotiable.; Black's kingside pawns (g7, h7) advance slowly. Pure pawn race against d-pawn loses by tempo. Blockade strategy is safer than counterplay alone.; White's king on e2 is poorly positioned to defend both d-pawn blockade and kingside simultaneously. Exploit this lag with king activation, forcing zugzwang or concession..
    • 6. Candidates3220 tok · 28777ms · claude-haiku-4-5 · $0.0161

      Candidates: Kc4 (Directly threatens d3 blockade; forces White to choose between advancing d3 or defending with king.) | g5 (Initiates kingside counterplay and passed-pawn threat while king blockades d-pawn. Dual-pressure…

      • chess.js.legal_moves0ms
      • llm.candidates28776ms · $0.0161
      full reasoning
      Candidates: Kc4 (Directly threatens d3 blockade; forces White to choose between advancing d3 or defending with king.) | g5 (Initiates kingside counterplay and passed-pawn threat while king blockades d-pawn. Dual-pressure strategy.) | Kc5 (Alternative king centralization toward blockade; maintains flexibility and threatens d4. Supports primary strategy.)
    • 7. Verify0 tok · 0ms

      Alle 3 Kandidaten legal. cloud_eval disabled (default).

      • chess.js.legal_recheck0ms
    • 8. Reflect1210 tok · 18287ms · claude-haiku-4-5 · $0.0060

      Final pick: Kc4 — Directly threatens d3 blockade, forcing White to choose between advancing d3 or defending with king. Most forcing continuation exploiting White's poorly positioned king.. Rejected: g7g5, b4c5.

      • llm.reflect18286ms · $0.0060
    • 9. Commit0 tok · 0ms

      Commit Kc4 (b4c4).

  69. 69.Ke3Sonnet739 tok · $0.0110 · 37219ms
    • 1. Observe0 tok · 0ms

      Halbzug 69, Weiss am Zug. Phase: Endspiel. Weiss +1 Punkte. Legale Zuege: 11. Criticality: 0.15.

      • material-counter0ms
    • 2. Recall Position0 tok · 19ms

      recall: 5 similar position(s) found (limit=5).

      • nex_search19ms
    • 3. Recall Opponent0 tok · 6ms

      No pattern found for chess-haiku-tm (tag=chess-haiku-tm) — mandatory run documented.

      • nex_entity_search6ms
    • 4. Research0 tok · 0ms · skipped

      middlegame/endgame — research not relevant when both tools off.

    • 5. Plan282 tok · 10589ms · claude-sonnet-4-6 · $0.0042

      Phase: endgame. Advance White king to e3/d3 to shield d2 and f2 pawns, then escort the d-pawn toward promotion while maintaining opposition against Black king on c4 to prevent infiltration. Use king opposition principles…

      • llm.plan10589ms · $0.0042
      full reasoning
      Phase: endgame. Advance White king to e3/d3 to shield d2 and f2 pawns, then escort the d-pawn toward promotion while maintaining opposition against Black king on c4 to prevent infiltration. Use king opposition principles to outmaneuver the Black king and escort one pawn — ideally d2 — to promotion, reaching a winning K+Q vs K endgame. Critical: Black king on c4 directly threatens d2 and e2 squares — White king must interpose immediately on e3 or d3; Memory hit [ENDGAME opposition]: White must seize direct opposition to push Black king back from the promotion path; h2/g7 and h7 pawns are irrelevant short-term; focus entirely on the d2 pawn escort with king centralization; White king on e2 is the key move — blocks Black king from d3 and shields d2, enabling controlled pawn advance.
    • 6. Candidates251 tok · 17251ms · claude-sonnet-4-6 · $0.0037

      Candidates: Ke3 (Seizes opposition against Black king on c4, shields d2 pawn, controls d3/f3 — endgame opposition principle directly applied.) | d3+ (Advances d-pawn with check, forcing Black king back and accelerating p…

      • chess.js.legal_moves0ms
      • llm.candidates17251ms · $0.0037
      full reasoning
      Candidates: Ke3 (Seizes opposition against Black king on c4, shields d2 pawn, controls d3/f3 — endgame opposition principle directly applied.) | d3+ (Advances d-pawn with check, forcing Black king back and accelerating promotion escort; trades tempo for pawn progress.) | d4 (Pushes d-pawn two squares toward promotion while Black king on c4 cannot immediately capture; gains space on promotion path.)
    • 7. Verify0 tok · 0ms

      Alle 3 Kandidaten legal. cloud_eval disabled (default).

      • chess.js.legal_recheck0ms
    • 8. Reflect206 tok · 9341ms · claude-sonnet-4-6 · $0.0031

      Final pick: Ke3 — Seizes direct opposition against Black king on c4, blocking infiltration to d3/d2. Memory heuristic [ENDGAME opposition]: king must interpose immediately. Ke3 shields d2 and controls d3/f3 before advanc…

      • llm.reflect9341ms · $0.0031
      full reasoning
      Final pick: Ke3 — Seizes direct opposition against Black king on c4, blocking infiltration to d3/d2. Memory heuristic [ENDGAME opposition]: king must interpose immediately. Ke3 shields d2 and controls d3/f3 before advancing the pawn.. Rejected: d2d3, d2d4.
    • 9. Commit0 tok · 0ms

      Commit Ke3 (e2e3).

  70. 70...Kd5Haiku7.041 tok · $0.0351 · 72439ms
    • 1. Observe0 tok · 0ms

      Halbzug 70, Schwarz am Zug. Phase: Endspiel. Weiss +1 Punkte. Legale Zuege: 9. Criticality: 0.15.

      • material-counter0ms
    • 2. Recall Position0 tok · 10ms

      recall: 5 similar position(s) found (limit=5).

      • nex_search10ms
    • 3. Recall Opponent0 tok · 5ms

      No pattern found for chess-sonnet-tm (tag=chess-sonnet-tm) — mandatory run documented.

      • nex_entity_search5ms
    • 4. Research0 tok · 0ms · skipped

      middlegame/endgame — research not relevant when both tools off.

    • 5. Plan3332 tok · 30292ms · claude-haiku-4-5 · $0.0166

      Phase: endgame. Centralize king to blockade White's most dangerous pawn. Force White to defend or accept stalled position. Kingside pawns generate counterplay, tying down White's king. Draw via permanent blockade of adva…

      • llm.plan30292ms · $0.0166
      full reasoning
      Phase: endgame. Centralize king to blockade White's most dangerous pawn. Force White to defend or accept stalled position. Kingside pawns generate counterplay, tying down White's king. Draw via permanent blockade of advanced pawn while kingside pawns maintain enough counterplay to prevent breakthrough. White's king remains tied to defense. Critical: Opponent's pawn must not advance unopposed—blockade is critical; Own king centralization to blockading square before opponent pushes; Kingside pawns are only winning resource—must maintain as living threat; Opponent's king is constrained to pawn defense; exploit this rigidity.
    • 6. Candidates2180 tok · 23756ms · claude-haiku-4-5 · $0.0109

      Candidates: Kd5 (Blockade d2-pawn on d5 immediately. Centralizes king per plan, prevents d3 advance before White pushes.) | g5 (Aggressive kingside push (2 squares). Creates faster counterplay threat, forces White's king…

      • chess.js.legal_moves0ms
      • llm.candidates23755ms · $0.0109
      full reasoning
      Candidates: Kd5 (Blockade d2-pawn on d5 immediately. Centralizes king per plan, prevents d3 advance before White pushes.) | g5 (Aggressive kingside push (2 squares). Creates faster counterplay threat, forces White's king to defend multiple fronts.) | g6 (Sustained kingside pawn advance. Creates living counterplay threat while blockade holds d5. Tighter control.)
    • 7. Verify0 tok · 0ms

      Alle 3 Kandidaten legal. cloud_eval disabled (default).

      • chess.js.legal_recheck0ms
    • 8. Reflect1529 tok · 18365ms · claude-haiku-4-5 · $0.0076

      Final pick: Kd5 — Blockade d2-pawn immediately on d5, centralizing king before White pushes. Prevents opponent's main threat while maintaining kingside counterplay.. Rejected: g7g5, g7g6.

      • llm.reflect18365ms · $0.0076
    • 9. Commit0 tok · 0ms

      Commit Kd5 (c4d5).

  71. 71.Kd3Sonnet768 tok · $0.0114 · 28118ms
    • 1. Observe0 tok · 0ms

      Halbzug 71, Weiss am Zug. Phase: Endspiel. Weiss +1 Punkte. Legale Zuege: 10. Criticality: 0.15.

      • material-counter0ms
    • 2. Recall Position0 tok · 19ms

      recall: 5 similar position(s) found (limit=5).

      • nex_search19ms
    • 3. Recall Opponent0 tok · 12ms

      No pattern found for chess-haiku-tm (tag=chess-haiku-tm) — mandatory run documented.

      • nex_entity_search12ms
    • 4. Research0 tok · 0ms · skipped

      middlegame/endgame — research not relevant when both tools off.

    • 5. Plan303 tok · 10610ms · claude-sonnet-4-6 · $0.0045

      Phase: endgame. Advance White king toward d3 to shield d2-pawn, seize opposition against Black king on d5, then escort d2 or f2 pawn to promotion while Black king is kept at bay Use king opposition to freeze the Black ki…

      • llm.plan10610ms · $0.0045
      full reasoning
      Phase: endgame. Advance White king toward d3 to shield d2-pawn, seize opposition against Black king on d5, then escort d2 or f2 pawn to promotion while Black king is kept at bay Use king opposition to freeze the Black king out of the promotion path and march one White pawn — ideally d2 — to queen, converting the material advantage into a won K+Q vs K endgame. Critical: Black king on d5 is centralized and dangerously close to both d2 and f2 pawns — White king must seize direct opposition immediately; Memory hit [ENDGAME opposition]: White king must achieve direct opposition (e3 vs d5 diagonal approach, or d3 directly in front of d2-pawn) to push Black king back from the promotion corridor; h2-pawn and Black g7/h7 pawns are irrelevant in the short term — the d2 and f2 pawns are the winning instruments; do not allow Black king to reach c3 or e3.
    • 6. Candidates262 tok · 8514ms · claude-sonnet-4-6 · $0.0039

      Candidates: Kd3 (Seizes direct opposition in front of d2-pawn; memory hit [ENDGAME opposition]: Kd3 freezes Black king away from c3/e3 promotion corridors.) | Ke2 (King escorts d2-pawn from behind; blocks Black king entr…

      • chess.js.legal_moves0ms
      • llm.candidates8513ms · $0.0039
      full reasoning
      Candidates: Kd3 (Seizes direct opposition in front of d2-pawn; memory hit [ENDGAME opposition]: Kd3 freezes Black king away from c3/e3 promotion corridors.) | Ke2 (King escorts d2-pawn from behind; blocks Black king entry to e3 while preparing to advance pawn safely.) | d4 (Advances d-pawn toward promotion, gains space; pawn structure improvement per heuristic suggestion, forcing Black king to react.)
    • 7. Verify0 tok · 1ms

      Alle 3 Kandidaten legal. cloud_eval disabled (default).

      • chess.js.legal_recheck0ms
    • 8. Reflect203 tok · 8946ms · claude-sonnet-4-6 · $0.0030

      Final pick: Kd3 — Seizes direct opposition in front of d2-pawn, freezing Black king on d5 away from c3/e3. Memory heuristic [ENDGAME opposition] confirmed: Kd3 controls c3 and e3 simultaneously, preventing Black king fro…

      • llm.reflect8946ms · $0.0030
      full reasoning
      Final pick: Kd3 — Seizes direct opposition in front of d2-pawn, freezing Black king on d5 away from c3/e3. Memory heuristic [ENDGAME opposition] confirmed: Kd3 controls c3 and e3 simultaneously, preventing Black king from entering the promotion corridor.. Rejected: e3e2, d2d4.
    • 9. Commit0 tok · 0ms

      Commit Kd3 (e3d3).

  72. 72...g5Haiku7.030 tok · $0.0350 · 84017ms
    • 1. Observe0 tok · 1ms

      Halbzug 72, Schwarz am Zug. Phase: Endspiel. Weiss +1 Punkte. Legale Zuege: 9. Criticality: 0.15.

      • material-counter0ms
    • 2. Recall Position0 tok · 12ms

      recall: 5 similar position(s) found (limit=5).

      • nex_search12ms
    • 3. Recall Opponent0 tok · 5ms

      No pattern found for chess-sonnet-tm (tag=chess-sonnet-tm) — mandatory run documented.

      • nex_entity_search5ms
    • 4. Research0 tok · 0ms · skipped

      middlegame/endgame — research not relevant when both tools off.

    • 5. Plan2155 tok · 23867ms · claude-haiku-4-5 · $0.0107

      Phase: endgame. Blockade d-pawn with king while advancing kingside pawns to create dual threats. Force White to choose: support d-pawn (allowing g/h pawns breakthrough) or stop kingside (letting blockade crack). Draw via…

      • llm.plan23867ms · $0.0107
      full reasoning
      Phase: endgame. Blockade d-pawn with king while advancing kingside pawns to create dual threats. Force White to choose: support d-pawn (allowing g/h pawns breakthrough) or stop kingside (letting blockade crack). Draw via perpetual blockade of d-pawn combined with kingside pawn counterplay; maintain zugzwang-like position where White cannot constructively advance without abandoning pawn support. Critical: d-pawn advance (d3-d4) must be blockaded—opponent's most dangerous threat; kingside pawns must advance with tempo to create second front (not stall); White's king cannot simultaneously defend d-pawn and stop g7/h7 breakthroughs.
    • 6. Candidates3062 tok · 35323ms · claude-haiku-4-5 · $0.0153

      Candidates: Ke5 (Centralizes king, maintains blockade flexibility while preparing kingside support) | g6 (Advances kingside pawn creating second-front threat, maintains d-pawn blockade) | g5 (Pushes kingside pawn with te…

      • chess.js.legal_moves0ms
      • llm.candidates35322ms · $0.0153
      full reasoning
      Candidates: Ke5 (Centralizes king, maintains blockade flexibility while preparing kingside support) | g6 (Advances kingside pawn creating second-front threat, maintains d-pawn blockade) | g5 (Pushes kingside pawn with tempo, forces position toward endgame breakthrough)
    • 7. Verify0 tok · 1ms

      Alle 3 Kandidaten legal. cloud_eval disabled (default).

      • chess.js.legal_recheck0ms
    • 8. Reflect1813 tok · 24798ms · claude-haiku-4-5 · $0.0090

      Final pick: g5 — Creates tempo by threatening g4 with kingside breakthrough, forces White to choose between advancing d4 (allowing g4 tactic) or defending kingside, maintaining zugzwang where both objectives can't be met…

      • llm.reflect24798ms · $0.0090
      full reasoning
      Final pick: g5 — Creates tempo by threatening g4 with kingside breakthrough, forces White to choose between advancing d4 (allowing g4 tactic) or defending kingside, maintaining zugzwang where both objectives can't be met simultaneously.. Rejected: d5e5, g7g6.
    • 9. Commit0 tok · 0ms

      Commit g5 (g7g5).

  73. 73.Ke2Sonnet913 tok · $0.0136 · 31248ms
    • 1. Observe0 tok · 0ms

      Halbzug 73, Weiss am Zug. Phase: Endspiel. Weiss +1 Punkte. Legale Zuege: 8. Criticality: 0.15.

      • material-counter0ms
    • 2. Recall Position0 tok · 17ms

      recall: 5 similar position(s) found (limit=5).

      • nex_search17ms
    • 3. Recall Opponent0 tok · 7ms

      No pattern found for chess-haiku-tm (tag=chess-haiku-tm) — mandatory run documented.

      • nex_entity_search7ms
    • 4. Research0 tok · 0ms · skipped

      middlegame/endgame — research not relevant when both tools off.

    • 5. Plan278 tok · 10378ms · claude-sonnet-4-6 · $0.0041

      Phase: endgame. Seize direct opposition against Black king on d5, then escort d2-pawn toward promotion while keeping Black king away from the queening square Convert the extra pawn into a queen by using king opposition (…

      • llm.plan10378ms · $0.0041
      full reasoning
      Phase: endgame. Seize direct opposition against Black king on d5, then escort d2-pawn toward promotion while keeping Black king away from the queening square Convert the extra pawn into a queen by using king opposition (memory: ENDGAME opposition) to freeze the Black king out of d1/e1 and march d2 to d8 Critical: Black king on d5 is dangerously close to d2 and f2 — White king must achieve direct opposition immediately (e4 or c4 to challenge d5); Memory heuristic [ENDGAME opposition]: White must hold opposition to push Black king back from the pawn promotion path; Black g5/h7 pawns are passed but far — White ignores them for now and focuses on d2 promotion race; No rook present, so Philidor/Lucena memory hits are irrelevant here — pure K+P endgame logic applies.
    • 6. Candidates476 tok · 11387ms · claude-sonnet-4-6 · $0.0071

      Candidates: Ke3 (Steps toward e4 opposition next move; keeps king near d2 pawn escort route.) | Ke2 (Guards d2 pawn directly and prepares to escort it toward promotion square.)

      • chess.js.legal_moves0ms
      • llm.candidates11387ms · $0.0071
    • 7. Verify0 tok · 1ms

      Alle 2 Kandidaten legal. cloud_eval disabled (default).

      • chess.js.legal_recheck0ms
    • 8. Reflect159 tok · 9443ms · claude-sonnet-4-6 · $0.0023

      Final pick: Ke2 — Ke2 directly guards d2 pawn and takes the key escort square. Black king on d5 cannot reach d2 in time — White king on e2 controls d1/d3 and marches the pawn immediately.. Rejected: d3e3.

      • llm.reflect9443ms · $0.0023
    • 9. Commit0 tok · 0ms

      Commit Ke2 (d3e2).

  74. 74...Kd4Haiku17.600 tok · $0.0879 · 156977ms
    • 1. Observe0 tok · 0ms

      Halbzug 74, Schwarz am Zug. Phase: Endspiel. Weiss +1 Punkte. Legale Zuege: 11. Criticality: 0.15.

      • material-counter0ms
    • 2. Recall Position0 tok · 21ms

      recall: 5 similar position(s) found (limit=5).

      • nex_search21ms
    • 3. Recall Opponent0 tok · 7ms

      No pattern found for chess-sonnet-tm (tag=chess-sonnet-tm) — mandatory run documented.

      • nex_entity_search7ms
    • 4. Research0 tok · 0ms · skipped

      middlegame/endgame — research not relevant when both tools off.

    • 5. Plan2296 tok · 25778ms · claude-haiku-4-5 · $0.0114

      Phase: endgame. Blockade White's d-pawn with king while advancing kingside pawns (g4, h5) to create second front. Force zugzwang: White cannot safely defend both d-pawn and kingside threats. Draw via perpetual blockade +…

      • llm.plan25778ms · $0.0114
      full reasoning
      Phase: endgame. Blockade White's d-pawn with king while advancing kingside pawns (g4, h5) to create second front. Force zugzwang: White cannot safely defend both d-pawn and kingside threats. Draw via perpetual blockade + kingside counterplay. Hold draw despite material deficit by creating two independent threats that White cannot address simultaneously—d-pawn blockade plus kingside pawn breakthrough—maintaining zugzwang until both sides approach parity or perpetual stalemate. Critical: d2-d3-d4 sequence is White's winning attempt; blockade with Kd5 must be maintained; g5-g4 breakthrough must happen with tempo before White king reaches kingside; If g/h pawns stall without creating real threats, White's material advantage converts—time pressure against Black; White king mobility: if it defends d-pawn, kingside runs; if it stops kingside, d-pawn dies. Zugzwang window is narrow..
    • 6. Candidates5707 tok · 48747ms · claude-haiku-4-5 · $0.0285

      Candidates: Kd4 (Directly attack d-pawn, force White's response, initiate blockade while preparing kingside breakthrough) | g4 (Push kingside pawn with tempo, create second front, force zugzwang where White cannot defend…

      • chess.js.legal_moves0ms
      • llm.candidates48745ms · $0.0285
      full reasoning
      Candidates: Kd4 (Directly attack d-pawn, force White's response, initiate blockade while preparing kingside breakthrough) | g4 (Push kingside pawn with tempo, create second front, force zugzwang where White cannot defend both) | Ke5 (Centralize king supporting kingside pawns, maintain d-pawn pressure from distance, prepare zugzwang)
    • 7. Verify0 tok · 0ms

      Alle 3 Kandidaten legal. cloud_eval disabled (default).

      • chess.js.legal_recheck0ms
    • 8. Reflect9597 tok · 82410ms · claude-haiku-4-5 · $0.0479

      Final pick: Kd4 — Directly blockades d2 pawn on d4, preventing d3 advance. Next g4 creates two threats White cannot defend. Forces zugzwang.. Rejected: g5g4, d5e5.

      • llm.reflect82410ms · $0.0479
    • 9. Commit0 tok · 0ms

      Commit Kd4 (d5d4).

  75. 75.Ke1Sonnet691 tok · $0.0103 · 31779ms
    • 1. Observe0 tok · 0ms

      Halbzug 75, Weiss am Zug. Phase: Endspiel. Weiss +1 Punkte. Legale Zuege: 9. Criticality: 0.15.

      • material-counter0ms
    • 2. Recall Position0 tok · 14ms

      recall: 5 similar position(s) found (limit=5).

      • nex_search14ms
    • 3. Recall Opponent0 tok · 5ms

      No pattern found for chess-haiku-tm (tag=chess-haiku-tm) — mandatory run documented.

      • nex_entity_search5ms
    • 4. Research0 tok · 0ms · skipped

      middlegame/endgame — research not relevant when both tools off.

    • 5. Plan251 tok · 10969ms · claude-sonnet-4-6 · $0.0037

      Phase: endgame. Achieve direct opposition against Black king on d4, then escort the d2-pawn toward promotion while keeping Black king away from d1/e1 queening path over 3-5 moves Use king opposition (memory: ENDGAME oppo…

      • llm.plan10969ms · $0.0037
      full reasoning
      Phase: endgame. Achieve direct opposition against Black king on d4, then escort the d2-pawn toward promotion while keeping Black king away from d1/e1 queening path over 3-5 moves Use king opposition (memory: ENDGAME opposition) to freeze Black king out of the promotion square and convert the d2-pawn to a queen before Black's g5/h7 pawns become threatening. Critical: Black king on d4 is one step from d2-pawn — White king must achieve direct opposition immediately (e3 challenges d4); Memory [ENDGAME opposition]: White must hold opposition to push Black king back from d2/d1 promotion path; Black g5-pawn is a passed pawn — if White king wanders too far, Black queens first; pawn race awareness essential.
    • 6. Candidates252 tok · 10399ms · claude-sonnet-4-6 · $0.0037

      Candidates: Ke1 (Direct opposition: Ke1 vs Kd4 forces Black king back, clearing d2-pawn's promotion path to d1/e1.) | Kf3 (Kf3 approaches d4 diagonally, maintaining king activity while watching Black's g5 pawn threat.) |…

      • chess.js.legal_moves0ms
      • llm.candidates10399ms · $0.0037
      full reasoning
      Candidates: Ke1 (Direct opposition: Ke1 vs Kd4 forces Black king back, clearing d2-pawn's promotion path to d1/e1.) | Kf3 (Kf3 approaches d4 diagonally, maintaining king activity while watching Black's g5 pawn threat.) | d3 (Advances pawn with tempo, forcing Black king to react; pawn race awareness — d3 threatens d4 square.)
    • 7. Verify0 tok · 1ms

      Alle 3 Kandidaten legal. cloud_eval disabled (default).

      • chess.js.legal_recheck0ms
    • 8. Reflect188 tok · 10378ms · claude-sonnet-4-6 · $0.0028

      Final pick: Ke1 — Direct opposition: Ke1 vs Kd4 forces Black king back from d2/d1 promotion path. Memory heuristic ENDGAME opposition confirmed — White king on e1 holds direct opposition, Black must yield, allowing d2-d1…

      • llm.reflect10378ms · $0.0028
      full reasoning
      Final pick: Ke1 — Direct opposition: Ke1 vs Kd4 forces Black king back from d2/d1 promotion path. Memory heuristic ENDGAME opposition confirmed — White king on e1 holds direct opposition, Black must yield, allowing d2-d1 promotion.. Rejected: e2f3, d2d3.
    • 9. Commit0 tok · 0ms

      Commit Ke1 (e2e1).

  76. 76...g4Haiku17.814 tok · $0.0890 · 166157ms
    • 1. Observe0 tok · 1ms

      Halbzug 76, Schwarz am Zug. Phase: Endspiel. Weiss +1 Punkte. Legale Zuege: 9. Criticality: 0.15.

      • material-counter0ms
    • 2. Recall Position0 tok · 18ms

      recall: 5 similar position(s) found (limit=5).

      • nex_search18ms
    • 3. Recall Opponent0 tok · 7ms

      No pattern found for chess-sonnet-tm (tag=chess-sonnet-tm) — mandatory run documented.

      • nex_entity_search7ms
    • 4. Research0 tok · 0ms · skipped

      middlegame/endgame — research not relevant when both tools off.

    • 5. Plan1702 tok · 20269ms · claude-haiku-4-5 · $0.0085

      Phase: endgame. Blockade d2-pawn with Kd5 or Kd3 while launching g5→g4→h5 kingside breakthrough. Force zugzwang: White cannot simultaneously defend the d-pawn AND stop the kingside threat. Draw via perpetual blockade com…

      • llm.plan20269ms · $0.0085
      full reasoning
      Phase: endgame. Blockade d2-pawn with Kd5 or Kd3 while launching g5→g4→h5 kingside breakthrough. Force zugzwang: White cannot simultaneously defend the d-pawn AND stop the kingside threat. Draw via perpetual blockade combined with kingside pawn counterplay. Two independent threats (d-pawn blockade + g/h pawn breakthrough) exhaust White's defensive resources. Critical: d2 pawn advances to d3-d4 and wins if unblocked—blockade with Kd5/Kd3 is mandatory; Black down material (2 pawns vs 3)—passive play loses; must create second front NOW; g4 breakthrough is only drawing resource; after g4, h5 follows to create real threat White cannot ignore.
    • 6. Candidates7380 tok · 64272ms · claude-haiku-4-5 · $0.0369

      Candidates: g4 (Launches g5→g4→h5 kingside breakthrough creating second front. Forces zugzwang: White cannot defend d-pawn and kingside pawns simultaneously.) | Kd5 (Blockades d2-pawn from strong central square while sup…

      • chess.js.legal_moves0ms
      • llm.candidates64271ms · $0.0369
      full reasoning
      Candidates: g4 (Launches g5→g4→h5 kingside breakthrough creating second front. Forces zugzwang: White cannot defend d-pawn and kingside pawns simultaneously.) | Kd5 (Blockades d2-pawn from strong central square while supporting kingside breakthrough. Prevents d3-d4 White advance, mandatory per plan.) | Kd3 (Most restrictive blockade of d2-pawn, sitting adjacent. Prevents d3 push directly while enabling draw-by-zugzwang strategy. Mandatory blockading option.)
    • 7. Verify0 tok · 1ms

      Alle 3 Kandidaten legal. cloud_eval disabled (default).

      • chess.js.legal_recheck0ms
    • 8. Reflect8732 tok · 81577ms · claude-haiku-4-5 · $0.0436

      Final pick: g4 — g4 forces White's immediate response (d3 or f3), launching kingside breakthrough now. Passive King moves allow d3-d4 advance before Black's kingside threatens materialize. Tempo critical when down materi…

      • llm.reflect81577ms · $0.0436
      full reasoning
      Final pick: g4 — g4 forces White's immediate response (d3 or f3), launching kingside breakthrough now. Passive King moves allow d3-d4 advance before Black's kingside threatens materialize. Tempo critical when down material.. Rejected: d4d5, d4d3.
    • 9. Commit0 tok · 0ms

      Commit g4 (g5g4).

  77. 77.Ke2Sonnet673 tok · $0.0100 · 29197ms
    • 1. Observe0 tok · 0ms

      Halbzug 77, Weiss am Zug. Phase: Endspiel. Weiss +1 Punkte. Legale Zuege: 8. Criticality: 0.15.

      • material-counter0ms
    • 2. Recall Position0 tok · 8ms

      recall: 5 similar position(s) found (limit=5).

      • nex_search8ms
    • 3. Recall Opponent0 tok · 5ms

      No pattern found for chess-haiku-tm (tag=chess-haiku-tm) — mandatory run documented.

      • nex_entity_search5ms
    • 4. Research0 tok · 0ms · skipped

      middlegame/endgame — research not relevant when both tools off.

    • 5. Plan245 tok · 10408ms · claude-sonnet-4-6 · $0.0036

      Phase: endgame. Achieve direct opposition on e3 vs d4 to freeze Black king, then escort d2-pawn to promotion while preventing Black king from reaching d1/e1 queening square over 3-5 moves. Convert the d2-pawn to a queen …

      • llm.plan10408ms · $0.0036
      full reasoning
      Phase: endgame. Achieve direct opposition on e3 vs d4 to freeze Black king, then escort d2-pawn to promotion while preventing Black king from reaching d1/e1 queening square over 3-5 moves. Convert the d2-pawn to a queen using king opposition (memory: ENDGAME opposition) before Black's g4/h7 pawns become dangerous, keeping White king between Black king and the promotion path. Critical: Black king on d4 is one step from d2 — White king must occupy e3 immediately to achieve direct opposition and deny d3/d2 entry; Memory [ENDGAME opposition]: holding opposition forces Black king back from promotion squares d1/e1; Black g4-pawn is a long-term counter-threat — must queen d2 before g4 advances further.
    • 6. Candidates247 tok · 9396ms · claude-sonnet-4-6 · $0.0037

      Candidates: Ke2 (Centralizes king toward e3 opposition zone; blocks Black king from d2/e1 entry per ENDGAME opposition memory heuristic.) | d3 (Advances pawn closer to promotion; forces Black king to respond, supporting …

      • chess.js.legal_moves0ms
      • llm.candidates9396ms · $0.0037
      full reasoning
      Candidates: Ke2 (Centralizes king toward e3 opposition zone; blocks Black king from d2/e1 entry per ENDGAME opposition memory heuristic.) | d3 (Advances pawn closer to promotion; forces Black king to respond, supporting king opposition plan on e3.) | Kd1 (Guards d2 promotion square directly; denies Black king on d4 immediate entry to d3/d2 critical squares.)
    • 7. Verify0 tok · 1ms

      Alle 3 Kandidaten legal. cloud_eval disabled (default).

      • chess.js.legal_recheck0ms
    • 8. Reflect181 tok · 9371ms · claude-sonnet-4-6 · $0.0027

      Final pick: Ke2 — Ke2 achieves direct opposition against Black king on d4 next move (Ke3 = opposition), blocking d3/d2 entry per ENDGAME opposition memory. King must lead the pawn, not trail it.. Rejected: d2d3, e1d1.

      • llm.reflect9371ms · $0.0027
    • 9. Commit0 tok · 0ms

      Commit Ke2 (e1e2).

  78. 78...h5Haiku8.368 tok · $0.0417 · 84959ms
    • 1. Observe0 tok · 0ms

      Halbzug 78, Schwarz am Zug. Phase: Endspiel. Weiss +1 Punkte. Legale Zuege: 8. Criticality: 0.15.

      • material-counter0ms
    • 2. Recall Position0 tok · 10ms

      recall: 5 similar position(s) found (limit=5).

      • nex_search10ms
    • 3. Recall Opponent0 tok · 6ms

      No pattern found for chess-sonnet-tm (tag=chess-sonnet-tm) — mandatory run documented.

      • nex_entity_search6ms
    • 4. Research0 tok · 0ms · skipped

      middlegame/endgame — research not relevant when both tools off.

    • 5. Plan3462 tok · 33265ms · claude-haiku-4-5 · $0.0173

      Phase: endgame. Blockade d2 with Kd3 or Kd5 while launching h4→h3 and h7→h5/h6 kingside breakthrough. Force White into zugzwang: cannot defend d-pawn AND stop kingside threat simultaneously. Draw through perpetual blocka…

      • llm.plan33265ms · $0.0173
      full reasoning
      Phase: endgame. Blockade d2 with Kd3 or Kd5 while launching h4→h3 and h7→h5/h6 kingside breakthrough. Force White into zugzwang: cannot defend d-pawn AND stop kingside threat simultaneously. Draw through perpetual blockade of d2 combined with h-pawn counterplay; sacrifice one h-pawn if needed to stop White's pawns while promoting survivor. Critical: d2-pawn advance unstoppable if unblocked; h-pawns must advance NOW to create second threat; White cannot defend both threats—zugzwang key to survival.
    • 6. Candidates2880 tok · 29418ms · claude-haiku-4-5 · $0.0144

      Candidates: Kd5 (Blockade d2-pawn from ideal square. Prevents d3 advance, forces White into zugzwang: cannot defend d-pawn AND stop kingside simultaneously.) | h5 (Launch kingside breakthrough NOW. Creates second unstopp…

      • chess.js.legal_moves0ms
      • llm.candidates29417ms · $0.0144
      full reasoning
      Candidates: Kd5 (Blockade d2-pawn from ideal square. Prevents d3 advance, forces White into zugzwang: cannot defend d-pawn AND stop kingside simultaneously.) | h5 (Launch kingside breakthrough NOW. Creates second unstoppable threat independent of blockade; h-pawn becomes dangerous while d2 is pinned down.) | g3 (Aggressive g-pawn push toward g2. Forces f2xg3 or creates imminent promotion threat; spreads White's defense across two flanks.)
    • 7. Verify0 tok · 1ms

      Alle 3 Kandidaten legal. cloud_eval disabled (default).

      • chess.js.legal_recheck0ms
    • 8. Reflect2026 tok · 22251ms · claude-haiku-4-5 · $0.0101

      Final pick: h5 — h5 forces zugzwang immediately. White's king cannot defend d2-pawn and stop h4-h3 breakthrough simultaneously. Creates second threat NOW before d3 materializes.. Rejected: d4d5, g4g3.

      • llm.reflect22251ms · $0.0101
    • 9. Commit0 tok · 0ms

      Commit h5 (h7h5).

  79. 79.Ke1Sonnet665 tok · $0.0099 · 28174ms
    • 1. Observe0 tok · 0ms

      Halbzug 79, Weiss am Zug. Phase: Endspiel. Weiss +1 Punkte. Legale Zuege: 8. Criticality: 0.15.

      • material-counter0ms
    • 2. Recall Position0 tok · 15ms

      recall: 5 similar position(s) found (limit=5).

      • nex_search15ms
    • 3. Recall Opponent0 tok · 5ms

      No pattern found for chess-haiku-tm (tag=chess-haiku-tm) — mandatory run documented.

      • nex_entity_search5ms
    • 4. Research0 tok · 0ms · skipped

      middlegame/endgame — research not relevant when both tools off.

    • 5. Plan213 tok · 9851ms · claude-sonnet-4-6 · $0.0032

      Phase: endgame. Occupy e3 to achieve direct opposition against Black king on d4, freezing it and clearing the path for d2-pawn promotion over the next 3-5 moves. Convert the d2-pawn to a queen by maintaining king opposit…

      • llm.plan9851ms · $0.0032
      full reasoning
      Phase: endgame. Occupy e3 to achieve direct opposition against Black king on d4, freezing it and clearing the path for d2-pawn promotion over the next 3-5 moves. Convert the d2-pawn to a queen by maintaining king opposition (memory: ENDGAME opposition) and preventing Black king from reaching d1/e1 before White queens. Critical: Black king on d4 is one step from d2 — White king must reach e3 immediately; Black g4/h5 pawns are passed but slow; White must queen before they advance critically; Memory [ENDGAME opposition]: direct opposition on e3 vs d4 forces Black king away from promotion square.
    • 6. Candidates252 tok · 9395ms · claude-sonnet-4-6 · $0.0037

      Candidates: Ke1 (Sidesteps to e1, clearing path to e2-e3 next move, establishing opposition vs Black king on d4.) | Kf1 (Kf1-e2-e3 route achieves opposition in two moves; avoids stepping toward d1 where Black king threat…

      • chess.js.legal_moves0ms
      • llm.candidates9395ms · $0.0037
      full reasoning
      Candidates: Ke1 (Sidesteps to e1, clearing path to e2-e3 next move, establishing opposition vs Black king on d4.) | Kf1 (Kf1-e2-e3 route achieves opposition in two moves; avoids stepping toward d1 where Black king threatens d2-pawn.) | d3 (Advances d-pawn toward promotion, but risks Black king on d4 capturing immediately — memory: king safety first.)
    • 7. Verify0 tok · 1ms

      Alle 3 Kandidaten legal. cloud_eval disabled (default).

      • chess.js.legal_recheck0ms
    • 8. Reflect200 tok · 8892ms · claude-sonnet-4-6 · $0.0030

      Final pick: Ke1 — Ke1 reaches e2 next move and then e3 in two moves, establishing direct opposition vs Black king on d4. Memory [ENDGAME opposition]: direct opposition on e3 vs d4 freezes Black king away from d2 promotio…

      • llm.reflect8892ms · $0.0030
      full reasoning
      Final pick: Ke1 — Ke1 reaches e2 next move and then e3 in two moves, establishing direct opposition vs Black king on d4. Memory [ENDGAME opposition]: direct opposition on e3 vs d4 freezes Black king away from d2 promotion square.. Rejected: e2f1, d2d3.
    • 9. Commit0 tok · 0ms

      Commit Ke1 (e2e1).

  80. 80...Kd3Haiku11.784 tok · $0.0588 · 115879ms
    • 1. Observe0 tok · 0ms

      Halbzug 80, Schwarz am Zug. Phase: Endspiel. Weiss +1 Punkte. Legale Zuege: 8. Criticality: 0.15.

      • material-counter0ms
    • 2. Recall Position0 tok · 17ms

      recall: 5 similar position(s) found (limit=5).

      • nex_search17ms
    • 3. Recall Opponent0 tok · 7ms

      No pattern found for chess-sonnet-tm (tag=chess-sonnet-tm) — mandatory run documented.

      • nex_entity_search7ms
    • 4. Research0 tok · 0ms · skipped

      middlegame/endgame — research not relevant when both tools off.

    • 5. Plan3330 tok · 32287ms · claude-haiku-4-5 · $0.0166

      Phase: endgame. Blockade d2 with Kd3, launch h-pawn counterattack (h4→h3, h5 advance), force White into zugzwang by creating dual threats king cannot meet. Achieve draw through perpetual d2-blockade combined with unstopp…

      • llm.plan32287ms · $0.0166
      full reasoning
      Phase: endgame. Blockade d2 with Kd3, launch h-pawn counterattack (h4→h3, h5 advance), force White into zugzwang by creating dual threats king cannot meet. Achieve draw through perpetual d2-blockade combined with unstoppable h-pawn breakthrough that forces White to abandon one critical threat. Critical: d2-pawn must be blockaded immediately before reaching d3; h-pawns must advance now to create real counterplay while blockade holds; White cannot defend both d2 and kingside simultaneously—zugzwang is the only surviving mechanism.
    • 6. Candidates2140 tok · 27321ms · claude-haiku-4-5 · $0.0107

      Candidates: Kd3 (Blockade d2 pawn immediately, prevent d3 advance, lock White's threat permanently) | h4 (Launch h-pawn breakthrough h4→h3→h2, force White to defend kingside while d2 blockaded) | g3 (Create dual h/g pawn…

      • chess.js.legal_moves0ms
      • llm.candidates27320ms · $0.0107
      full reasoning
      Candidates: Kd3 (Blockade d2 pawn immediately, prevent d3 advance, lock White's threat permanently) | h4 (Launch h-pawn breakthrough h4→h3→h2, force White to defend kingside while d2 blockaded) | g3 (Create dual h/g pawn threats, force White king into zugzwang defending multiple breaks)
    • 7. Verify0 tok · 0ms

      Alle 3 Kandidaten legal. cloud_eval disabled (default).

      • chess.js.legal_recheck0ms
    • 8. Reflect6314 tok · 56235ms · claude-haiku-4-5 · $0.0315

      Final pick: Kd3 — Blockade d2 pawn immediately by occupying d3, eliminating White's main threat. Forces White king into zugzwang: if Kd1 (support), then h4 breaks kingside while pawn stays locked; if Kf3 (attack pawns), …

      • llm.reflect56235ms · $0.0315
      full reasoning
      Final pick: Kd3 — Blockade d2 pawn immediately by occupying d3, eliminating White's main threat. Forces White king into zugzwang: if Kd1 (support), then h4 breaks kingside while pawn stays locked; if Kf3 (attack pawns), then Kxd2 wins it outright. Dual-threat zugzwang only emerges after blockade is secure.. Rejected: h5h4, g4g3.
    • 9. Commit0 tok · 1ms

      Commit Kd3 (d4d3).

  81. 81.Kd1Sonnet660 tok · $0.0098 · 27884ms
    • 1. Observe0 tok · 0ms

      Halbzug 81, Weiss am Zug. Phase: Endspiel. Weiss +1 Punkte. Legale Zuege: 6. Criticality: 0.15.

      • material-counter0ms
    • 2. Recall Position0 tok · 9ms

      recall: 5 similar position(s) found (limit=5).

      • nex_search9ms
    • 3. Recall Opponent0 tok · 5ms

      No pattern found for chess-haiku-tm (tag=chess-haiku-tm) — mandatory run documented.

      • nex_entity_search5ms
    • 4. Research0 tok · 0ms · skipped

      middlegame/endgame — research not relevant when both tools off.

    • 5. Plan233 tok · 10378ms · claude-sonnet-4-6 · $0.0035

      Phase: endgame. Maintain king opposition on e3 to freeze Black king on d3/d4, then advance d2-pawn toward promotion. Memory [ENDGAME opposition]: direct opposition forces Black king away from d1/e1 promotion squares. Bla…

      • llm.plan10378ms · $0.0035
      full reasoning
      Phase: endgame. Maintain king opposition on e3 to freeze Black king on d3/d4, then advance d2-pawn toward promotion. Memory [ENDGAME opposition]: direct opposition forces Black king away from d1/e1 promotion squares. Black g4/h5 pawns are distant; White must queen d2 before they become critical. Queen the d2-pawn by holding king opposition and preventing Black king from blocking or capturing on d1. Critical: Black king on d3 is one step from d2 — White king must contest e3 immediately; Black g4/h5 passed pawns are slow but will advance if White king drifts; f2/h2 pawns are static anchors, not promotion threats — d2 is the winning pawn.
    • 6. Candidates244 tok · 9444ms · claude-sonnet-4-6 · $0.0036

      Candidates: Kd1 (Direct opposition heuristic: king contests d2 promotion square, blocks Black king on d3 from capturing d2.) | Kf1 (Sidesteps Black king, prepares to re-establish opposition on e2/d1 next move while guard…

      • chess.js.legal_moves0ms
      • llm.candidates9444ms · $0.0036
      full reasoning
      Candidates: Kd1 (Direct opposition heuristic: king contests d2 promotion square, blocks Black king on d3 from capturing d2.) | Kf1 (Sidesteps Black king, prepares to re-establish opposition on e2/d1 next move while guarding f2 anchor pawn.) | f3 (Static anchor pawn advance; slows Black king infiltration via e3 and keeps pawn structure solid.)
    • 7. Verify0 tok · 0ms

      Alle 3 Kandidaten legal. cloud_eval disabled (default).

      • chess.js.legal_recheck0ms
    • 8. Reflect183 tok · 8039ms · claude-sonnet-4-6 · $0.0027

      Final pick: Kd1 — Direct opposition on d1 contests the d2 promotion square immediately. Black king on d3 cannot capture d2 without stepping into opposition loss. Memory heuristic: king opposition freezes Black king from …

      • llm.reflect8039ms · $0.0027
      full reasoning
      Final pick: Kd1 — Direct opposition on d1 contests the d2 promotion square immediately. Black king on d3 cannot capture d2 without stepping into opposition loss. Memory heuristic: king opposition freezes Black king from blocking promotion.. Rejected: e1f1, f2f3.
    • 9. Commit0 tok · 0ms

      Commit Kd1 (e1d1).

  82. 82...g3Haiku13.894 tok · $0.0694 · 134275ms
    • 1. Observe0 tok · 0ms

      Halbzug 82, Schwarz am Zug. Phase: Endspiel. Weiss +1 Punkte. Legale Zuege: 5. Criticality: 0.35.

      • material-counter0ms
    • 2. Recall Position0 tok · 12ms

      recall: 5 similar position(s) found (limit=5).

      • nex_search12ms
    • 3. Recall Opponent0 tok · 8ms

      No pattern found for chess-sonnet-tm (tag=chess-sonnet-tm) — mandatory run documented.

      • nex_entity_search8ms
    • 4. Research0 tok · 0ms · skipped

      middlegame/endgame — research not relevant when both tools off.

    • 5. Plan3151 tok · 32756ms · claude-haiku-4-5 · $0.0157

      Phase: endgame. Advance kingside pawns to create dual threats while maintaining blockade on White's center pawn. Force White king into zugzwang where defending the advanced pawn and stopping pawns becomes impossible. Ach…

      • llm.plan32756ms · $0.0157
      full reasoning
      Phase: endgame. Advance kingside pawns to create dual threats while maintaining blockade on White's center pawn. Force White king into zugzwang where defending the advanced pawn and stopping pawns becomes impossible. Achieve draw through perpetual blockade equilibrium. Convert material deficit into perpetual draw by achieving zugzwang: White king cannot defend both the d-pawn blockade and contain kingside promotion threats, making any move suboptimal for White. Critical: Blockade of advanced White pawn is critical—must be maintained or White promotes; Kingside pawns must accelerate now while blockade holds, before White defensive consolidation; White king geometry creates inherent zugzwang potential—defending multiple threats simultaneously is impossible.
    • 6. Candidates4627 tok · 43775ms · claude-haiku-4-5 · $0.0231

      Candidates: g3 (Accelerates g-pawn to maximum threat (2 moves to queen). Creates dual promotion threats forcing White king into zugzwang defending blockade and stopping pawns.) | h4 (Advances h-pawn while maintaining blo…

      • chess.js.legal_moves0ms
      • llm.candidates43774ms · $0.0231
      full reasoning
      Candidates: g3 (Accelerates g-pawn to maximum threat (2 moves to queen). Creates dual promotion threats forcing White king into zugzwang defending blockade and stopping pawns.) | h4 (Advances h-pawn while maintaining blockade. Creates unstoppable kingside threats. White must choose defending d-pawn or stopping promotion.) | Kd4 (Maintains blockade (king controls d3) while centralizing. Optimizes zugzwang positioning—White cannot defend d-pawn and stop both kingside pawns.)
    • 7. Verify0 tok · 1ms

      Alle 3 Kandidaten legal. cloud_eval disabled (default).

      • chess.js.legal_recheck0ms
    • 8. Reflect6116 tok · 57715ms · claude-haiku-4-5 · $0.0305

      Final pick: g3 — Accelerates g-pawn immediately (2 moves to queen). Forces White into zugzwang where defending d-pawn blockade and stopping promotion threat simultaneously becomes impossible. Maximally forcing.. Rejected…

      • llm.reflect57715ms · $0.0305
      full reasoning
      Final pick: g3 — Accelerates g-pawn immediately (2 moves to queen). Forces White into zugzwang where defending d-pawn blockade and stopping promotion threat simultaneously becomes impossible. Maximally forcing.. Rejected: h5h4, d3d4.
    • 9. Commit0 tok · 0ms

      Commit g3 (g4g3).

  83. 83.Ke1Sonnet747 tok · $0.0111 · 29785ms
    • 1. Observe0 tok · 0ms

      Halbzug 83, Weiss am Zug. Phase: Endspiel. Weiss +1 Punkte. Legale Zuege: 8. Criticality: 0.15.

      • material-counter0ms
    • 2. Recall Position0 tok · 7ms

      recall: 5 similar position(s) found (limit=5).

      • nex_search7ms
    • 3. Recall Opponent0 tok · 8ms

      No pattern found for chess-haiku-tm (tag=chess-haiku-tm) — mandatory run documented.

      • nex_entity_search8ms
    • 4. Research0 tok · 0ms · skipped

      middlegame/endgame — research not relevant when both tools off.

    • 5. Plan294 tok · 10935ms · claude-sonnet-4-6 · $0.0044

      Phase: endgame. Maintain or recapture king opposition to freeze Black king away from d2, then advance d2-pawn toward promotion while keeping f2/h2 as anchors. Queen the d2-pawn by using king opposition (heuristic: [ENDGA…

      • llm.plan10935ms · $0.0044
      full reasoning
      Phase: endgame. Maintain or recapture king opposition to freeze Black king away from d2, then advance d2-pawn toward promotion while keeping f2/h2 as anchors. Queen the d2-pawn by using king opposition (heuristic: [ENDGAME opposition] — opposition forces Black king back from d1/e1 promotion squares) before Black's distant g3/h5 pawns become threats. Critical: Black king on d3 threatens to step to d2 or e2 and block/capture the d2-pawn — White king must contest e3 immediately; Black g3-pawn is one step from g2, dangerous if White king drifts; h5-pawn is slower; Heuristic [ENDGAME opposition]: direct opposition on e3 is the key mechanism — without it Black king penetrates to d2 and wins the pawn; f2 and h2 pawns are static anchors, not promotion candidates; focus is solely on d2.
    • 6. Candidates252 tok · 9437ms · claude-sonnet-4-6 · $0.0037

      Candidates: Ke1 (King moves toward e2/e3 to contest opposition against Black king on d3, protecting d2-pawn from capture.) | fxg3 (Eliminates dangerous g3-pawn one step from g2; heuristic [ENDGAME opposition] — removing …

      • chess.js.legal_moves0ms
      • llm.candidates9436ms · $0.0037
      full reasoning
      Candidates: Ke1 (King moves toward e2/e3 to contest opposition against Black king on d3, protecting d2-pawn from capture.) | fxg3 (Eliminates dangerous g3-pawn one step from g2; heuristic [ENDGAME opposition] — removing threats lets king focus on d2.) | hxg3 (Alternative pawn capture on g3, anchors h-file structure while neutralizing Black's most advanced passed pawn threat.)
    • 7. Verify0 tok · 1ms

      Alle 3 Kandidaten legal. cloud_eval disabled (default).

      • chess.js.legal_recheck0ms
    • 8. Reflect201 tok · 9388ms · claude-sonnet-4-6 · $0.0030

      Final pick: Ke1 — King must contest opposition immediately — heuristic [ENDGAME opposition] requires White king on e2/e3 to freeze Black king away from d2. Without Ke1→e2→e3, Black king steps to d2 and captures or blocks…

      • llm.reflect9387ms · $0.0030
      full reasoning
      Final pick: Ke1 — King must contest opposition immediately — heuristic [ENDGAME opposition] requires White king on e2/e3 to freeze Black king away from d2. Without Ke1→e2→e3, Black king steps to d2 and captures or blocks the pawn.. Rejected: f2g3, h2g3.
    • 9. Commit0 tok · 0ms

      Commit Ke1 (d1e1).

  84. 84...gxf2+Haiku13.086 tok · $0.0653 · 122932ms
    • 1. Observe0 tok · 0ms

      Halbzug 84, Schwarz am Zug. Phase: Endspiel. Weiss +1 Punkte. Legale Zuege: 8. Criticality: 0.15.

      • material-counter0ms
    • 2. Recall Position0 tok · 8ms

      recall: 5 similar position(s) found (limit=5).

      • nex_search8ms
    • 3. Recall Opponent0 tok · 6ms

      No pattern found for chess-sonnet-tm (tag=chess-sonnet-tm) — mandatory run documented.

      • nex_entity_search6ms
    • 4. Research0 tok · 0ms · skipped

      middlegame/endgame — research not relevant when both tools off.

    • 5. Plan9399 tok · 81152ms · claude-haiku-4-5 · $0.0470

      Phase: endgame. Push g3→g2 and advance h5→h4 to create dual kingside threats forcing White king response. Maintain blockade of d2 pawn. Achieve promotion race win or force zugzwang. Race Black's g-pawn to promotion (g2, …

      • llm.plan81152ms · $0.0470
      full reasoning
      Phase: endgame. Push g3→g2 and advance h5→h4 to create dual kingside threats forcing White king response. Maintain blockade of d2 pawn. Achieve promotion race win or force zugzwang. Race Black's g-pawn to promotion (g2, g1+) before White d2 can advance past blockade. If White diverts king to stop kingside, d2 becomes undefended. Draw via perpetual blockade if promotion race fails. Critical: d2 pawn must remain blockaded—king cannot abandon d-file; g3 pawn is 2 moves from queening—this is Black's main asset; White king on e1 is too distant to support f2/h2 defense or d2 attack; h5 pawn serves as secondary threat; even one promotion force wins.
    • 6. Candidates2287 tok · 22738ms · claude-haiku-4-5 · $0.0114

      Candidates: gxf2+ (Check forces White king away; g1=Q threat next move. Wins promotion race.) | g2 (g-pawn advances one move from queening. g1=Q threat forces White immediate response.) | gxh2 (Removes kingside pawn; h1=…

      • chess.js.legal_moves0ms
      • llm.candidates22737ms · $0.0114
      full reasoning
      Candidates: gxf2+ (Check forces White king away; g1=Q threat next move. Wins promotion race.) | g2 (g-pawn advances one move from queening. g1=Q threat forces White immediate response.) | gxh2 (Removes kingside pawn; h1=Q threat next. Clears h-file, accelerates promotion.)
    • 7. Verify0 tok · 1ms

      Alle 3 Kandidaten legal. cloud_eval disabled (default).

      • chess.js.legal_recheck0ms
    • 8. Reflect1400 tok · 19017ms · claude-haiku-4-5 · $0.0070

      Final pick: gxf2+ — gxf2+ forces the king away with check. After any king move (Kd1, Ke2, Kf1), g2 is unstoppable and g1=Q follows. Wins the race.. Rejected: g3g2, g3h2.

      • llm.reflect19017ms · $0.0070
    • 9. Commit0 tok · 0ms

      Commit gxf2+ (g3f2).

  85. 85.Kd1Sonnet682 tok · $0.0101 · 30656ms
    • 1. Observe0 tok · 0ms

      Halbzug 85, Weiss am Zug. Phase: Endspiel. Material gleich. Legale Zuege: 3. Schach! Criticality: 0.60.

      • material-counter0ms
    • 2. Recall Position0 tok · 12ms

      recall: 5 similar position(s) found (limit=5).

      • nex_search12ms
    • 3. Recall Opponent0 tok · 8ms

      No pattern found for chess-haiku-tm (tag=chess-haiku-tm) — mandatory run documented.

      • nex_entity_search8ms
    • 4. Research0 tok · 0ms · skipped

      middlegame/endgame — research not relevant when both tools off.

    • 5. Plan265 tok · 13199ms · claude-sonnet-4-6 · $0.0039

      Phase: endgame. Contest e3 immediately to deny Black king access to d2/e2. The d2-pawn is our winning asset — Black king on d3 threatens to step directly onto d2 and capture it. White king must seize opposition to freeze…

      • llm.plan13199ms · $0.0039
      full reasoning
      Phase: endgame. Contest e3 immediately to deny Black king access to d2/e2. The d2-pawn is our winning asset — Black king on d3 threatens to step directly onto d2 and capture it. White king must seize opposition to freeze Black king and shepherd d2 to promotion. Use king opposition (heuristic: [ENDGAME opposition]) to drive Black king away from d2, promote the d-pawn before Black's f2-pawn promotes, accepting trade if necessary. Critical: Black king d3 threatens d2-pawn capture next move; f2-pawn is one step from promotion — Black queens if White ignores it; h5-pawn is distant and slow; White has only 3 legal moves — must choose the one that contests d2-pawn survival; opposition heuristic: White king must reach e3 or f3 to maintain tension against Black king.
    • 6. Candidates239 tok · 8875ms · claude-sonnet-4-6 · $0.0035

      Candidates: Kxf2 (Captures f2-pawn immediately, eliminating Black's promotion threat while keeping king active near d2.) | Kd1 (King guards d2-pawn directly; contests Black king on d3 with opposition, freezing enemy king…

      • chess.js.legal_moves0ms
      • llm.candidates8875ms · $0.0035
      full reasoning
      Candidates: Kxf2 (Captures f2-pawn immediately, eliminating Black's promotion threat while keeping king active near d2.) | Kd1 (King guards d2-pawn directly; contests Black king on d3 with opposition, freezing enemy king.) | Kf1 (Prepares Kxf2 next while staying near d2; avoids immediate pawn loss but tempo is slow.)
    • 7. Verify0 tok · 1ms

      Alle 3 Kandidaten legal. cloud_eval disabled (default).

      • chess.js.legal_recheck0ms
    • 8. Reflect178 tok · 8551ms · claude-sonnet-4-6 · $0.0026

      Final pick: Kd1 — Direct opposition against Black king on d3 freezes it — Black king cannot step to d2 or e2. Guards d2-pawn while applying opposition principle; White wins the pawn race.. Rejected: e1f2, e1f1.

      • llm.reflect8551ms · $0.0026
    • 9. Commit0 tok · 0ms

      Commit Kd1 (e1d1).

  86. 86...f1=Q#Haiku14.834 tok · $0.0741 · 140037ms
    • 1. Observe0 tok · 0ms

      Halbzug 86, Schwarz am Zug. Phase: Endspiel. Material gleich. Legale Zuege: 8. Criticality: 0.15.

      • material-counter0ms
    • 2. Recall Position0 tok · 12ms

      recall: 5 similar position(s) found (limit=5).

      • nex_search12ms
    • 3. Recall Opponent0 tok · 6ms

      No pattern found for chess-sonnet-tm (tag=chess-sonnet-tm) — mandatory run documented.

      • nex_entity_search6ms
    • 4. Research0 tok · 0ms · skipped

      middlegame/endgame — research not relevant when both tools off.

    • 5. Plan2672 tok · 35277ms · claude-haiku-4-5 · $0.0133

      Phase: endgame. Force f2→f1=Q immediately, or extract White concessions (d2 abandonment) to enable promotion. Dual-threaten with h5→h4 if White diverts. Achieve queen-promotion within 1-2 moves. Promote the f-pawn to a q…

      • llm.plan35277ms · $0.0133
      full reasoning
      Phase: endgame. Force f2→f1=Q immediately, or extract White concessions (d2 abandonment) to enable promotion. Dual-threaten with h5→h4 if White diverts. Achieve queen-promotion within 1-2 moves. Promote the f-pawn to a queen before White's d2 can advance past the blockade, converting material equality into a winning advantage. Critical: f2 pawn is one move from queening; this is Black's only immediate threat and dominates White's response; d2 pawn is blockaded by Black's king (Kd3); if king moves away, d2 marches but f1=Q still wins; if king stays, promotion is unstoppable; White king on d1 is too distant to defend the kingside (h2) or stop f1=Q; must choose between defending d2 or moving toward f-pawn; h5 pawn as secondary threat (h5→h4) forces White to account for multiple tactics; h2 is immobile and defenseless; zugzwang structure: White cannot improve position without losing d2 or allowing promotion.
    • 6. Candidates6808 tok · 57366ms · claude-haiku-4-5 · $0.0340

      Candidates: f1=R# (Promotes f-pawn to rook, delivering immediate checkmate. King on d1 has no escape.) | f1=Q# (Promotes f-pawn to queen, delivering immediate checkmate. Wins game immediately.) | Kd4 (Centralizes king wh…

      • chess.js.legal_moves0ms
      • llm.candidates57365ms · $0.0340
      full reasoning
      Candidates: f1=R# (Promotes f-pawn to rook, delivering immediate checkmate. King on d1 has no escape.) | f1=Q# (Promotes f-pawn to queen, delivering immediate checkmate. Wins game immediately.) | Kd4 (Centralizes king while maintaining blockade on d2 pawn. Prepares secondary threats.)
    • 7. Verify0 tok · 1ms

      Alle 3 Kandidaten legal. cloud_eval disabled (default).

      • chess.js.legal_recheck0ms
    • 8. Reflect5354 tok · 47357ms · claude-haiku-4-5 · $0.0267

      Final pick: f1=Q# — f1=Q delivers checkmate immediately. Rook underpromotion unnecessary; queen ensures fastest victory. King move abandons winning promotion.. Rejected: f2f1r, d3d4.

      • llm.reflect47356ms · $0.0267
    • 9. Commit0 tok · 0ms

      Commit f1=Q# (f2f1q).

PGN

PGN anzeigen
[Event "Tournament Pairing 5"]
[Site "?"]
[Date "2026-05-30"]
[Round "?"]
[White "chess-sonnet-tm"]
[Black "chess-haiku-tm"]
[Result "*"]

1. e4 d5 2. exd5 Nf6 3. Nf3 Qxd5 4. Nc3 Nc6 5. Nxd5 Bg4 6. Nxc7+ Kd7 7. Bc4 Kxc7 8. Bxf7 Nd4 9. O-O Nxf3+ 10. Qxf3 Bxf3 11. gxf3 Nd5 12. Bxd5 e5 13. Rd1 e4 14. Bxb7 Kxb7 15. fxe4 Rc8 16. Re1 Rxc2 17. Re2 Rxc1+ 18. Rxc1 a5 19. Rc7+ Ka6 20. Ra7+ Kxa7 21. e5 a4 22. e6 a3 23. e7 Rg8 24. e8=Q Bd6 25. bxa3 Rxe8 26. Rxe8 Bb4 27. axb4 Ka6 28. b5+ Kxb5 29. Rb8+ Ka4 30. Rb4+ Ka3 31. Rb3+ Kxa2 32. Ra3+ Kxa3 33. Kf1 Kb4 34. Ke2 Kc4 35. Ke3 Kd5 36. Kd3 g5 37. Ke2 Kd4 38. Ke1 g4 39. Ke2 h5 40. Ke1 Kd3 41. Kd1 g3 42. Ke1 gxf2+ 43. Kd1 f1=Q# *