aklow labs·chess

SonnetvsSonnet

* · in progress · 0 Halbzuege · $1.3151 Kosten · 177 in / 87.638 out · Langfuse-Trace ↗

Keine Halbzuege — Spiel noch nicht begonnen.

Halbzuege (16)

  1. 1.e4Sonnet705 tok · $0.0105 · 30513ms
    • 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 · 3ms

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

      • nex_entity_search3ms
    • 4. Research0 tok · 0ms · skipped

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

    • 5. Plan262 tok · 12400ms · claude-sonnet-4-6 · $0.0039

      Phase: opening. Occupy the center with a pawn on e4, develop knights to f3 and c3, then bishops, and castle kingside within 7 moves. Aim for a classically strong pawn center that restricts Black's counterplay. Establish …

      • llm.plan12400ms · $0.0039
      full reasoning
      Phase: opening. Occupy the center with a pawn on e4, develop knights to f3 and c3, then bishops, and castle kingside within 7 moves. Aim for a classically strong pawn center that restricts Black's counterplay. Establish central dominance via e4+d4, develop all pieces harmoniously, and transition into middlegame with a spatial advantage and open lines for active piece play. Critical: No opponent threats on move 1 — full freedom to choose optimal opening structure; Memory confirms: central control (e4/d4) is the highest-priority opening principle; Memory confirms: knights before bishops — Nf3 should follow the first pawn move; 20 legal moves available; e4 or d4 are objectively strongest for central control; Avoid early queen development per heuristic — keep her back until development is complete.
    • 6. Candidates248 tok · 9377ms · claude-sonnet-4-6 · $0.0037

      Candidates: e4 (Occupies center immediately, opens diagonals for bishop and queen, enables rapid kingside development per classical principles.) | d4 (Claims central space with d-pawn, supports e4 follow-up, aligns with …

      • chess.js.legal_moves0ms
      • llm.candidates9374ms · $0.0037
      full reasoning
      Candidates: e4 (Occupies center immediately, opens diagonals for bishop and queen, enables rapid kingside development per classical principles.) | d4 (Claims central space with d-pawn, supports e4 follow-up, aligns with memory heuristic: central control is highest-priority opening principle.) | Nf3 (Knights before bishops heuristic confirmed in memory; controls e5/d4 central squares while keeping all pawn options open.)
    • 7. Verify0 tok · 1ms

      Alle 3 Kandidaten legal. cloud_eval disabled (default).

      • chess.js.legal_recheck0ms
    • 8. Reflect195 tok · 8544ms · claude-sonnet-4-6 · $0.0029

      Final pick: e4 — Immediately occupies the center, opens diagonals for Bc4 and the queen, and enables rapid Nf3+Bc4+0-0 kingside development — the most forcing start toward classical central dominance.. Rejected: d2d4, g1…

      • llm.reflect8543ms · $0.0029
      full reasoning
      Final pick: e4 — Immediately occupies the center, opens diagonals for Bc4 and the queen, and enables rapid Nf3+Bc4+0-0 kingside development — the most forcing start toward classical central dominance.. Rejected: d2d4, g1f3.
    • 9. Commit0 tok · 0ms

      Commit e4 (e2e4).

  2. 2...c5Sonnet3.254 tok · $0.0487 · 88835ms
    • 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 · 0ms · skipped

      recall_position disabled for this agent (tool_config.memory_recall=false).

    • 3. Recall Opponent0 tok · 0ms · skipped

      recall_opponent disabled for this agent (tool_config.memory_recall=false).

    • 4. Research0 tok · 504ms

      Web search returned no SearXNG results (empty).

      • web_search.searxng504ms · fail
    • 5. Plan1506 tok · 44253ms · claude-sonnet-4-6 · $0.0225

      Phase: opening. Challenge or undermine White's e4 space claim immediately. According to the Chess.com tiered analysis, Black's best practical options either fight symmetrically for the center or create asymmetric queensi…

      • llm.plan44253ms · $0.0225
      full reasoning
      Phase: opening. Challenge or undermine White's e4 space claim immediately. According to the Chess.com tiered analysis, Black's best practical options either fight symmetrically for the center or create asymmetric queenside counter-play. Goal: reach a position with clear piece-development plan and no structural weaknesses within 3–5 moves. Steer toward an asymmetric middlegame where Black can generate independent counter-play rather than merely reacting to White's initiative — the web research consistently ranks combative counter-central systems highest for Black winning chances. Critical: White's e4 pawn controls d5 and f5 — Black must decide whether to contest the center directly or undermine it from the flank; First-move choice locks in the entire opening repertoire — no neutral options exist; Development lag is zero now but conceding more center space for free would be a critical error.
    • 6. Candidates984 tok · 20834ms · claude-sonnet-4-6 · $0.0147

      Candidates: e5 (Classical symmetric counter-claim; directly contests e4 and establishes equal central presence from move one.) | c5 (Sicilian: asymmetric queenside counter-play, fights d4 not e4; web research ranks this …

      • chess.js.legal_moves0ms
      • llm.candidates20832ms · $0.0147
      full reasoning
      Candidates: e5 (Classical symmetric counter-claim; directly contests e4 and establishes equal central presence from move one.) | c5 (Sicilian: asymmetric queenside counter-play, fights d4 not e4; web research ranks this highest for Black winning chances.) | c6 (Caro-Kann setup; prepares …d5 to undermine e4 solidly while avoiding early concessions of structural weaknesses.)
    • 7. Verify0 tok · 2ms

      Alle 3 Kandidaten legal. cloud_eval disabled (default).

      • chess.js.legal_recheck0ms
    • 8. Reflect764 tok · 23226ms · claude-sonnet-4-6 · $0.0114

      Final pick: c5 — According to the plan's web research synthesis, the Sicilian ranks highest for Black winning chances — c5 contests d4, not e4, forcing asymmetric counterplay on the queenside while denying White a free s…

      • llm.reflect23226ms · $0.0114
      full reasoning
      Final pick: c5 — According to the plan's web research synthesis, the Sicilian ranks highest for Black winning chances — c5 contests d4, not e4, forcing asymmetric counterplay on the queenside while denying White a free symmetric center.. Rejected: e7e5, c7c6.
    • 9. Commit0 tok · 0ms

      Commit c5 (c7c5).

  3. 3.Nf3Sonnet2.611 tok · $0.0391 · 69467ms
    • 1. Observe0 tok · 0ms

      Halbzug 3, Weiss am Zug. Phase: Eroeffnung. Material gleich. Legale Zuege: 30. Criticality: 0.30.

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

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

      • nex_search19ms
    • 3. Recall Opponent0 tok · 4ms

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

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

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

    • 5. Plan1045 tok · 25735ms · claude-sonnet-4-6 · $0.0156

      Phase: opening. Play Nf3 per the 'knights before bishops' heuristic, then follow with d4 to challenge Black's c5 Sicilian pawn and open the center. After cxd4 Nxd4, develop Nc3 and a bishop toward the Open Sicilian struc…

      • llm.plan25735ms · $0.0156
      full reasoning
      Phase: opening. Play Nf3 per the 'knights before bishops' heuristic, then follow with d4 to challenge Black's c5 Sicilian pawn and open the center. After cxd4 Nxd4, develop Nc3 and a bishop toward the Open Sicilian structure — three moves that establish a lead in development and central tension. Execute the Open Sicilian: use the d4 pawn break to dismantle Black's central anchor on c5, achieve a spatial advantage with active piece play on the kingside and center, and transition to a middlegame where White's better-coordinated pieces exploit half-open d-file and kingside attacking chances. Critical: Black's c5 directly contests d4 — the central control heuristic (e4+d4) demands we push d4 soon or cede the initiative; Delaying Nf3 allows Black to consolidate the Sicilian without pressure — knights before bishops is the tiebreaker here; No immediate tactical threats from Black on move 2 — full freedom to develop optimally; Avoid premature queen development (queen-late heuristic) — no Qh5+ or similar gimmicks that lose tempo against solid Sicilian setups.
    • 6. Candidates239 tok · 10921ms · claude-sonnet-4-6 · $0.0035

      Candidates: Nf3 (Knights before bishops heuristic; develops piece, controls d4/e5, prepares Open Sicilian d4 break.) | d4 (Central control heuristic demands immediate d4 to dismantle Black's c5 anchor and seize initiativ…

      • chess.js.legal_moves0ms
      • llm.candidates10919ms · $0.0035
      full reasoning
      Candidates: Nf3 (Knights before bishops heuristic; develops piece, controls d4/e5, prepares Open Sicilian d4 break.) | d4 (Central control heuristic demands immediate d4 to dismantle Black's c5 anchor and seize initiative.) | Nc3 (Develops knight toward center, supports future d4 push, active piece play without committing pawns.)
    • 7. Verify0 tok · 1ms

      Alle 3 Kandidaten legal. cloud_eval disabled (default).

      • chess.js.legal_recheck0ms
    • 8. Reflect1327 tok · 32758ms · claude-sonnet-4-6 · $0.0199

      Final pick: Nf3 — Knights-before-bishops heuristic plus the central-control imperative both point here: Nf3 eyes d4 and e5 simultaneously, letting White play d4 next move with Nxd4 recapture available — no queen-tempo lo…

      • llm.reflect32758ms · $0.0199
      full reasoning
      Final pick: Nf3 — Knights-before-bishops heuristic plus the central-control imperative both point here: Nf3 eyes d4 and e5 simultaneously, letting White play d4 next move with Nxd4 recapture available — no queen-tempo loss.. Rejected: d2d4, b1c3.
    • 9. Commit0 tok · 0ms

      Commit Nf3 (g1f3).

  4. 4...Nf6Sonnet4.237 tok · $0.0634 · 100117ms
    • 1. Observe0 tok · 0ms

      Halbzug 4, Schwarz am Zug. Phase: Eroeffnung. Material gleich. Legale Zuege: 22. Criticality: 0.30.

      • material-counter0ms
    • 2. Recall Position0 tok · 0ms · skipped

      recall_position disabled for this agent (tool_config.memory_recall=false).

    • 3. Recall Opponent0 tok · 0ms · skipped

      recall_opponent disabled for this agent (tool_config.memory_recall=false).

    • 4. Research0 tok · 120ms

      Web search returned no SearXNG results (empty).

      • web_search.searxng120ms · fail
    • 5. Plan2040 tok · 52482ms · claude-sonnet-4-6 · $0.0305

      Phase: opening. Commit to an asymmetric Sicilian structure by preparing to meet White's d2-d4 advance. Black aims to recapture on d4 with a piece (not a pawn), keeping the pawn structure fluid. Over the next 3–5 moves: d…

      • llm.plan52482ms · $0.0305
      full reasoning
      Phase: opening. Commit to an asymmetric Sicilian structure by preparing to meet White's d2-d4 advance. Black aims to recapture on d4 with a piece (not a pawn), keeping the pawn structure fluid. Over the next 3–5 moves: develop the g8-knight to f6, aim for ...d7-d6 or ...e7-e6 to solidify the center, then castle kingside. Exploit the asymmetric pawn structure — Black's queenside c-file majority and potential ...d5 or ...b5 breaks will generate independent counterplay against White's central space advantage; according to the Chess.com Sicilian overview, this wing-vs-center tension is the defining strategic theme that gives Black the highest winning chances. Critical: White's imminent d2-d4 break must be met with a recapture that keeps the position dynamic; Avoiding 3.Bb5 Rossolimo lines that grant White comfortable positional pressure via Bxc6 doubling; No weakening of the d6 or e6 squares prematurely.
    • 6. Candidates1088 tok · 23231ms · claude-sonnet-4-6 · $0.0163

      Candidates: Nc6 (Classic Open Sicilian development; pressures e4 and prepares fluid cxd4/piece recapture as the plan demands.) | Nf6 (Plan explicitly targets g8-knight to f6; attacks e4, enables quick kingside castling.)…

      • chess.js.legal_moves0ms
      • llm.candidates23229ms · $0.0163
      full reasoning
      Candidates: Nc6 (Classic Open Sicilian development; pressures e4 and prepares fluid cxd4/piece recapture as the plan demands.) | Nf6 (Plan explicitly targets g8-knight to f6; attacks e4, enables quick kingside castling.) | d6 (Solidifies center per plan's Scheveningen/Najdorf approach; keeps e6 available for later structural flexibility.)
    • 7. Verify0 tok · 0ms

      Alle 3 Kandidaten legal. cloud_eval disabled (default).

      • chess.js.legal_recheck0ms
    • 8. Reflect1109 tok · 24264ms · claude-sonnet-4-6 · $0.0166

      Final pick: Nf6 — Plan explicitly targets g8-knight to f6; attacks e4 immediately; critically avoids inviting 3.Bb5 Rossolimo (only triggered by Nc6), which the plan warns grants White comfortable Bxc6 doubling pressure.…

      • llm.reflect24264ms · $0.0166
      full reasoning
      Final pick: Nf6 — Plan explicitly targets g8-knight to f6; attacks e4 immediately; critically avoids inviting 3.Bb5 Rossolimo (only triggered by Nc6), which the plan warns grants White comfortable Bxc6 doubling pressure.. Rejected: b8c6, d7d6.
    • 9. Commit0 tok · 0ms

      Commit Nf6 (g8f6).

  5. 5.Nc3Sonnet6.224 tok · $0.0933 · 131154ms
    • 1. Observe0 tok · 0ms

      Halbzug 5, Weiss am Zug. Phase: Eroeffnung. Material gleich. Legale Zuege: 28. Criticality: 0.30.

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

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

      • nex_search9ms
    • 3. Recall Opponent0 tok · 3ms

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

      • nex_entity_search3ms
    • 4. Research0 tok · 0ms · skipped

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

    • 5. Plan2522 tok · 57343ms · claude-sonnet-4-6 · $0.0378

      Phase: opening. Address the tactical pressure on e4 from Black's knight on f6 — either reinforce the center with the queen-knight, advance the e-pawn to force the knight back, or push the d-pawn break while accounting fo…

      • llm.plan57343ms · $0.0378
      full reasoning
      Phase: opening. Address the tactical pressure on e4 from Black's knight on f6 — either reinforce the center with the queen-knight, advance the e-pawn to force the knight back, or push the d-pawn break while accounting for the undefended e4 pawn. Develop the queen-knight and aim for rapid piece coordination. Three moves: stabilize center, develop knight, prepare bishop deployment. Dissolve Black's c5 anchor via the d-pawn break, seize central and spatial superiority in an Open Sicilian structure, and build a kingside initiative exploiting the half-open d-file and better-coordinated pieces — consistent with the heuristics 'knights before bishops' (Nf3 already executed) and 'central control' (e4 established, d4 next). Critical: Black's knight on f6 directly attacks the e4 pawn — the d-pawn break creates a moment where e4 is undefended and Black can capture it; must be calculated before committing; Own weakness: e4 pawn needs a defender (queen-knight to c3) or the pawn tension must be resolved by advancing before Black exploits it; Concrete tactical threat: if the d-pawn advances and Black captures, the f6 knight can immediately win the e4 pawn — this fork threat is the single highest-priority factor at this ply.
    • 6. Candidates254 tok · 10901ms · claude-sonnet-4-6 · $0.0038

      Candidates: Nc3 (Defends undefended e4 pawn immediately; follows 'knights before bishops' heuristic and enables d4 break safely.) | d4 (Central d-pawn break dissolves Black's c5 anchor; seizes spatial superiority in Open…

      • chess.js.legal_moves0ms
      • llm.candidates10897ms · $0.0038
      full reasoning
      Candidates: Nc3 (Defends undefended e4 pawn immediately; follows 'knights before bishops' heuristic and enables d4 break safely.) | d4 (Central d-pawn break dissolves Black's c5 anchor; seizes spatial superiority in Open Sicilian — but requires calculation of Nxe4 response.) | Bc4 (Develops bishop to active diagonal targeting f7; maintains central tension while preparing kingside initiative via piece coordination.)
    • 7. Verify0 tok · 2ms

      Alle 3 Kandidaten legal. cloud_eval disabled (default).

      • chess.js.legal_recheck0ms
    • 8. Reflect3448 tok · 62876ms · claude-sonnet-4-6 · $0.0517

      Final pick: Nc3 — Immediately plugs the undefended e4 pawn against Nxe4, follows 'knights before bishops' heuristic, and safely enables the d4 break next move without requiring any tactical calculation. Maximum control, …

      • llm.reflect62876ms · $0.0517
      full reasoning
      Final pick: Nc3 — Immediately plugs the undefended e4 pawn against Nxe4, follows 'knights before bishops' heuristic, and safely enables the d4 break next move without requiring any tactical calculation. Maximum control, zero risk.. Rejected: d2d4, f1c4.
    • 9. Commit0 tok · 0ms

      Commit Nc3 (b1c3).

  6. 6...Nc6Sonnet6.720 tok · $0.1006 · 148124ms
    • 1. Observe0 tok · 1ms

      Halbzug 6, Schwarz am Zug. Phase: Eroeffnung. Material gleich. Legale Zuege: 24. Criticality: 0.30.

      • material-counter0ms
    • 2. Recall Position0 tok · 0ms · skipped

      recall_position disabled for this agent (tool_config.memory_recall=false).

    • 3. Recall Opponent0 tok · 0ms · skipped

      recall_opponent disabled for this agent (tool_config.memory_recall=false).

    • 4. Research0 tok · 576ms

      Web search returned no SearXNG results (empty).

      • web_search.searxng576ms · fail
    • 5. Plan3131 tok · 73270ms · claude-sonnet-4-6 · $0.0469

      Phase: opening. Develop the b8-knight (to c6), play ...d7-d6 to brace the center, then castle kingside — all before White's d2-d4 thrust forces a reaction. The c5 pawn must stay as an outpost anchor, not a concession. Ex…

      • llm.plan73270ms · $0.0469
      full reasoning
      Phase: opening. Develop the b8-knight (to c6), play ...d7-d6 to brace the center, then castle kingside — all before White's d2-d4 thrust forces a reaction. The c5 pawn must stay as an outpost anchor, not a concession. Exploit the Sicilian asymmetry confirmed by the Chess.com overview: surrender the center temporarily to White's e4-d4 space, then generate independent queenside counterplay via the c-file and a future ...b5 break while White's central pawns become targets, not assets. Critical: White's primary threat is d2-d4 — must recapture with a piece (cxd4 Nxd4 or Nxd4) to avoid doubled or isolated c-pawns; Nf6 is tactically exposed if White plays e4-e5, forcing the knight back and losing tempo; ...d7-d6 neutralizes this immediately; Own weakness: b8-knight is still home, creating a development lag; delaying ...Nc6 risks White seizing full center before Black consolidates; No useful web result for the exact line 2.Nf3 Nf6 3.Nc3 — falling back to confirmed Sicilian general principles: wing-vs-center tension is the defining structural theme.
    • 6. Candidates1334 tok · 27958ms · claude-sonnet-4-6 · $0.0200

      Candidates: Nc6 (Plan explicitly names Nc6 as priority: closes development lag, anchors c5 pawn, prevents White's d4 thrust unopposed.) | d6 (Plan names d6 to neutralize e4-e5 threat against Nf6 and brace center before W…

      • chess.js.legal_moves0ms
      • llm.candidates27957ms · $0.0200
      full reasoning
      Candidates: Nc6 (Plan explicitly names Nc6 as priority: closes development lag, anchors c5 pawn, prevents White's d4 thrust unopposed.) | d6 (Plan names d6 to neutralize e4-e5 threat against Nf6 and brace center before White's d4 forces reaction.) | e6 (Prepares kingside castling per plan, solidifies center, and keeps Sicilian wing-vs-center asymmetry intact.)
    • 7. Verify0 tok · 1ms

      Alle 3 Kandidaten legal. cloud_eval disabled (default).

      • chess.js.legal_recheck0ms
    • 8. Reflect2255 tok · 46291ms · claude-sonnet-4-6 · $0.0338

      Final pick: Nc6 — Closes the development lag immediately while defending c5 concretely. After 4.d4 cxd4 5.Nxd4, Black recaptures with a piece (Nxd4) — the Classical Sicilian structure where White's d4-pawn vanishes and B…

      • llm.reflect46291ms · $0.0338
      full reasoning
      Final pick: Nc6 — Closes the development lag immediately while defending c5 concretely. After 4.d4 cxd4 5.Nxd4, Black recaptures with a piece (Nxd4) — the Classical Sicilian structure where White's d4-pawn vanishes and Black's queenside counterplay via ...b5 becomes the engine.. Rejected: d7d6, e7e6.
    • 9. Commit0 tok · 0ms

      Commit Nc6 (b8c6).

  7. 7.d4Sonnet2.737 tok · $0.0409 · 70584ms
    • 1. Observe0 tok · 0ms

      Halbzug 7, 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 · 3ms

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

      • nex_entity_search3ms
    • 4. Research0 tok · 0ms · skipped

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

    • 5. Plan1356 tok · 35825ms · claude-sonnet-4-6 · $0.0203

      Phase: opening. Push d4 to dissolve Black's c5 anchor and enter Open Sicilian. After d4 cxd4 Nxd4, recentralize the knight and deploy bishops actively. Three moves: d4 break, recapture on d4, develop dark-square bishop t…

      • llm.plan35825ms · $0.0203
      full reasoning
      Phase: opening. Push d4 to dissolve Black's c5 anchor and enter Open Sicilian. After d4 cxd4 Nxd4, recentralize the knight and deploy bishops actively. Three moves: d4 break, recapture on d4, develop dark-square bishop toward e3 or e2 while targeting kingside castling. Seize full center with d4-e4 pawn duo, recapture on d4 with the knight for dominant central control, then develop bishops and castle kingside before launching a coordinated kingside initiative against Black's uncastled king. Critical: Black Nf6 pressures e4 — d4 advances the center and makes e4 less of a target; Black c5 controls d4 — must be challenged immediately or White loses central grip; Both knights developed per heuristic 2; d4 now opens diagonals for bishops per heuristic 1 — timing is correct; Queen must stay back per heuristic 3 — next piece to move is a bishop, not the queen.
    • 6. Candidates243 tok · 9449ms · claude-sonnet-4-6 · $0.0036

      Candidates: d4 (Challenges c5 anchor directly, opens diagonals for bishops, establishes e4-d4 pawn duo for full center control.) | Bc4 (Active bishop development targeting f7, coordinates with Nf3 pressure, prepares king…

      • chess.js.legal_moves0ms
      • llm.candidates9446ms · $0.0036
      full reasoning
      Candidates: d4 (Challenges c5 anchor directly, opens diagonals for bishops, establishes e4-d4 pawn duo for full center control.) | Bc4 (Active bishop development targeting f7, coordinates with Nf3 pressure, prepares kingside castling rapidly.) | Bb5 (Pins Nc6, creates immediate tension, active piece play per Generation 0 directive without premature material sacrifice.)
    • 7. Verify0 tok · 0ms

      Alle 3 Kandidaten legal. cloud_eval disabled (default).

      • chess.js.legal_recheck0ms
    • 8. Reflect1138 tok · 25278ms · claude-sonnet-4-6 · $0.0170

      Final pick: d4 — Directly dissolves the c5 anchor per Generation 0 directive: after cxd4 Nxd4, White achieves the full e4-d4 duo, opens the c1-bishop diagonal (heuristic 1 — timing confirmed with both knights already act…

      • llm.reflect25278ms · $0.0170
      full reasoning
      Final pick: d4 — Directly dissolves the c5 anchor per Generation 0 directive: after cxd4 Nxd4, White achieves the full e4-d4 duo, opens the c1-bishop diagonal (heuristic 1 — timing confirmed with both knights already active per heuristic 2), and seizes uncontested central space.. Rejected: f1c4, f1b5.
    • 9. Commit0 tok · 0ms

      Commit d4 (d2d4).

  8. 8...e6Sonnet6.322 tok · $0.0947 · 128141ms
    • 1. Observe0 tok · 0ms

      Halbzug 8, Schwarz am Zug. Phase: Eroeffnung. Material gleich. Legale Zuege: 29. Criticality: 0.30.

      • material-counter0ms
    • 2. Recall Position0 tok · 0ms · skipped

      recall_position disabled for this agent (tool_config.memory_recall=false).

    • 3. Recall Opponent0 tok · 0ms · skipped

      recall_opponent disabled for this agent (tool_config.memory_recall=false).

    • 4. Research384 tok · 16839ms · claude-sonnet-4-6 · $0.0057

      Web search (opening, SearXNG + summary): This position arises from the Four Knights / Double-Pawn Opening complex — specifically resembling a Symmetrical English or a transposition into a Four Knights Game after 1.e4 c5 …

      • web_search.searxng2955ms
      • llm.research_summary13883ms · $0.0057
      full reasoning
      Web search (opening, SearXNG + summary): This position arises from the Four Knights / Double-Pawn Opening complex — specifically resembling a Symmetrical English or a transposition into a Four Knights Game after 1.e4 c5 2.Nf3 Nc6 3.d4 cxd4 4.Nxd4 (or similar), but the FEN shows Wh…
    • 5. Plan1953 tok · 37766ms · claude-sonnet-4-6 · $0.0293

      Phase: opening. Resolve central tension immediately — White's d4-e4 duo cannot be left unchallenged. Prioritize either ...cxd4 (simplifying into a Sicilian-type structure) or a direct central strike via ...e6 and ...d5 i…

      • llm.plan37766ms · $0.0293
      full reasoning
      Phase: opening. Resolve central tension immediately — White's d4-e4 duo cannot be left unchallenged. Prioritize either ...cxd4 (simplifying into a Sicilian-type structure) or a direct central strike via ...e6 and ...d5 in 2–3 moves, while activating the dark-squared bishop before kingside castling. Accept Sicilian asymmetry: surrender central space temporarily, complete development (Bc8 activation → kingside castle), then generate counterplay via the c-file, ...b5 queenside break, and pressure on White's eventually overextended central pawns. Critical: White's d4-e4 duo dominates space — passivity now concedes a structural advantage that compounds quickly; The dark-squared bishop on c8 is the key undeveloped piece; ...e6 unblocks it while also preparing ...d5; The c5 pawn is currently solid but could become a weakness if White plays d5, cramping Black's queenside; According to the web research synthesis, ...d5 or ...e6+...d5 is the principled response to this Four Knights/Sicilian hybrid — direct central confrontation over passive development.
    • 6. Candidates1577 tok · 29226ms · claude-sonnet-4-6 · $0.0236

      Candidates: e6 (Unblocks dark-squared bishop immediately, prepares ...d5 central break — plan's two-move strike sequence.) | cxd4 (Resolves central tension at once; plan explicitly cites ...cxd4 as simplifying into Sicil…

      • chess.js.legal_moves0ms
      • llm.candidates29224ms · $0.0236
      full reasoning
      Candidates: e6 (Unblocks dark-squared bishop immediately, prepares ...d5 central break — plan's two-move strike sequence.) | cxd4 (Resolves central tension at once; plan explicitly cites ...cxd4 as simplifying into Sicilian-type asymmetry.) | d5 (Immediate direct central confrontation; web research flags ...d5 as principled counter to White's d4-e4 duo.)
    • 7. Verify0 tok · 2ms

      Alle 3 Kandidaten legal. cloud_eval disabled (default).

      • chess.js.legal_recheck0ms
    • 8. Reflect2408 tok · 44286ms · claude-sonnet-4-6 · $0.0361

      Final pick: e6 — Prepares ...d5 when the c5 pawn is still safe. After e6, if White plays exd5 or d5, Black recaptures cleanly; the dark-squared bishop is unblocked; and the ...d5 central strike lands next move fully supp…

      • llm.reflect44286ms · $0.0361
      full reasoning
      Final pick: e6 — Prepares ...d5 when the c5 pawn is still safe. After e6, if White plays exd5 or d5, Black recaptures cleanly; the dark-squared bishop is unblocked; and the ...d5 central strike lands next move fully supported.. Rejected: c5d4, d7d5.
    • 9. Commit0 tok · 0ms

      Commit e6 (e7e6).

  9. 9.Bc4Sonnet5.100 tok · $0.0764 · 101569ms
    • 1. Observe0 tok · 0ms

      Halbzug 9, Weiss am Zug. Phase: Eroeffnung. Material gleich. Legale Zuege: 38. Criticality: 0.40.

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

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

      • nex_search11ms
    • 3. Recall Opponent0 tok · 4ms

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

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

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

    • 5. Plan1614 tok · 31279ms · claude-sonnet-4-6 · $0.0242

      Phase: opening. Develop dark-square bishop actively (Bc4 or Be3), maintain d4-e4 center tension, and castle kingside within 2 moves. The d4-c5 confrontation must be resolved: either d5 to gain space or dxc5 to open the d…

      • llm.plan31279ms · $0.0242
      full reasoning
      Phase: opening. Develop dark-square bishop actively (Bc4 or Be3), maintain d4-e4 center tension, and castle kingside within 2 moves. The d4-c5 confrontation must be resolved: either d5 to gain space or dxc5 to open the d-file. Memory heuristic 1 confirmed: d4+e4 already control the critical center squares — preserve that advantage. Use the d4-e4 space advantage to keep Black cramped in the center; with both knights developed (memory heuristic 2: knights before bishops fulfilled), now activate bishops and castle before launching a coordinated kingside attack against Black's uncastled king. Critical: Black Nf6 exerts pressure on e4 — any bishop development to c4 or e3 must account for this; Black c5 vs d4 tension: if Black plays cxd4 next, White recaptures with Nxd4 for dominant central knight; Black king still in center — do not allow Black to castle before we strike or equalize piece activity; d5 advance is a concrete option that gains space and reduces Black's c5 anchor.
    • 6. Candidates1251 tok · 23831ms · claude-sonnet-4-6 · $0.0187

      Candidates: Bc4 (Active bishop development targeting f7; enables kingside castling immediately; heuristic 1: preserves d4-e4 center while adding piece pressure.) | d5 (Resolves c5 tension with space gain; cramps Nc6; heu…

      • chess.js.legal_moves0ms
      • llm.candidates23825ms · $0.0187
      full reasoning
      Candidates: Bc4 (Active bishop development targeting f7; enables kingside castling immediately; heuristic 1: preserves d4-e4 center while adding piece pressure.) | d5 (Resolves c5 tension with space gain; cramps Nc6; heuristic 1: d4-e4 advantage expanded — reduces Black's c5 anchor per plan directive.) | Be3 (Active bishop development; reinforces d4 against c5 pressure; heuristic 2: completes bishop activation after knights, enabling castling next move.)
    • 7. Verify0 tok · 0ms

      Alle 3 Kandidaten legal. cloud_eval disabled (default).

      • chess.js.legal_recheck0ms
    • 8. Reflect2235 tok · 46427ms · claude-sonnet-4-6 · $0.0335

      Final pick: Bc4 — Targets f7 aggressively where Black's uncastled king is vulnerable; enables immediate O-O; maintains d4-e4 tension (heuristic 1) while threatening Ng5 next, creating multiple concrete threats before Bla…

      • llm.reflect46427ms · $0.0335
      full reasoning
      Final pick: Bc4 — Targets f7 aggressively where Black's uncastled king is vulnerable; enables immediate O-O; maintains d4-e4 tension (heuristic 1) while threatening Ng5 next, creating multiple concrete threats before Black completes development.. Rejected: d4d5, c1e3.
    • 9. Commit0 tok · 0ms

      Commit Bc4 (f1c4).

  10. 10...cxd4Sonnet9.349 tok · $0.1401 · 223058ms
    • 1. Observe0 tok · 0ms

      Halbzug 10, Schwarz am Zug. Phase: Eroeffnung. Material gleich. Legale Zuege: 32. Criticality: 0.30.

      • material-counter0ms
    • 2. Recall Position0 tok · 0ms · skipped

      recall_position disabled for this agent (tool_config.memory_recall=false).

    • 3. Recall Opponent0 tok · 0ms · skipped

      recall_opponent disabled for this agent (tool_config.memory_recall=false).

    • 4. Research0 tok · 333ms

      Web search returned no SearXNG results (empty).

      • web_search.searxng333ms · fail
    • 5. Plan5587 tok · 118967ms · claude-sonnet-4-6 · $0.0837

      Phase: opening. Capture cxd4 immediately to dissolve the d4–e4 tension and enter a Sicilian-type structure. After Nxd4 respond, develop the dark-squared bishop (Bc8 to e7 or b7), then castle kingside. Avoid passive waiti…

      • llm.plan118967ms · $0.0837
      full reasoning
      Phase: opening. Capture cxd4 immediately to dissolve the d4–e4 tension and enter a Sicilian-type structure. After Nxd4 respond, develop the dark-squared bishop (Bc8 to e7 or b7), then castle kingside. Avoid passive waiting — White consolidates a dominant center if Black dithers. Exploit Sicilian asymmetry post ...cxd4: open c-file pressure, queenside expansion via ...b5–b4 to hassle the d4 knight, and convert White's central space advantage into a target once pieces are active and the king is safe. Critical: According to the ChessBase article on 'Sicilian experiment 1.e4 c5 2.Nf3 Nc6 3.Bc4', Black's ...e6 already neutralizes the f7 pressure — Bc4 is structurally defused, but tactical f7 tricks return if Black delays castling; Bc8 is the single most critical undeveloped piece — no real counterplay until it activates; White can respond to passive play with e5, kicking Nf6 and gaining further space — so ...cxd4 must come now, not later.
    • 6. Candidates1023 tok · 21295ms · claude-sonnet-4-6 · $0.0153

      Candidates: cxd4 (Primary plan move: dissolves d4-e4 tension immediately, opens c-file, enters Sicilian asymmetry before White consolidates center.) | Be7 (Activates the critical dark-squared bishop, prepares kingside ca…

      • chess.js.legal_moves0ms
      • llm.candidates21293ms · $0.0153
      full reasoning
      Candidates: cxd4 (Primary plan move: dissolves d4-e4 tension immediately, opens c-file, enters Sicilian asymmetry before White consolidates center.) | Be7 (Activates the critical dark-squared bishop, prepares kingside castling, neutralizes f7 tactical tricks from Bc4.) | Nxd4 (Captures on d4 with tempo, challenges White's center directly and forces recapture, accelerating piece activity.)
    • 7. Verify0 tok · 0ms

      Alle 3 Kandidaten legal. cloud_eval disabled (default).

      • chess.js.legal_recheck0ms
    • 8. Reflect2739 tok · 82446ms · claude-sonnet-4-6 · $0.0410

      Final pick: cxd4 — According to the ChessBase Bc4-Sicilian article, cxd4 is the mainline response — opens the c-file, enters Sicilian asymmetry, and avoids the Bxf7+ tactical shot that refutes Nxd4.. Rejected: f8e7, c6d4…

      • llm.reflect82446ms · $0.0410
      full reasoning
      Final pick: cxd4 — According to the ChessBase Bc4-Sicilian article, cxd4 is the mainline response — opens the c-file, enters Sicilian asymmetry, and avoids the Bxf7+ tactical shot that refutes Nxd4.. Rejected: f8e7, c6d4.
    • 9. Commit0 tok · 0ms

      Commit cxd4 (c5d4).

  11. 11.Nxd4Sonnet8.948 tok · $0.1341 · 170433ms
    • 1. Observe0 tok · 0ms

      Halbzug 11, Weiss am Zug. Phase: Eroeffnung. Schwarz +1 Punkte. Legale Zuege: 44. Criticality: 0.40.

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

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

      • nex_search11ms
    • 3. Recall Opponent0 tok · 3ms

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

      • nex_entity_search3ms
    • 4. Research0 tok · 0ms · skipped

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

    • 5. Plan4217 tok · 77803ms · claude-sonnet-4-6 · $0.0632

      Phase: opening. Neutralize the d4 pawn immediately by capturing it (eliminating the ...dxc3 structural threat), then develop Bc1 to an active diagonal (Be3 or Bg5), and castle kingside. Memory heuristic 1 (central contro…

      • llm.plan77803ms · $0.0632
      full reasoning
      Phase: opening. Neutralize the d4 pawn immediately by capturing it (eliminating the ...dxc3 structural threat), then develop Bc1 to an active diagonal (Be3 or Bg5), and castle kingside. Memory heuristic 1 (central control) is at risk: the d4 pawn erodes White's e4–d4 grip — recapturing restores that advantage. Memory heuristic 2 (knights before bishops) is already satisfied; now priority shifts to bishop activation and king safety. After recapturing d4 and castling, exploit the active Bc4 diagonal against f7, coordinate rooks on central files, and press Black's king that remains in the center with no clear castling path in view. Critical: ...dxc3 threat — d4 pawn attacks Nc3 directly; this must be defused this move or next; White king in center at move 6 — every tempo spent not castling increases exposure; Bc1 idle — dark-square bishop must enter play alongside or immediately after resolving d4.
    • 6. Candidates2357 tok · 48333ms · claude-sonnet-4-6 · $0.0353

      Candidates: Nxd4 (Recaptures d4 restoring e4–d4 central grip (heuristic 1); knight to active post, eliminates ...dxc3 structural threat.) | Be3 (Activates idle dark-square bishop (plan priority, heuristic 2); fights d4 s…

      • chess.js.legal_moves0ms
      • llm.candidates48327ms · $0.0353
      full reasoning
      Candidates: Nxd4 (Recaptures d4 restoring e4–d4 central grip (heuristic 1); knight to active post, eliminates ...dxc3 structural threat.) | Be3 (Activates idle dark-square bishop (plan priority, heuristic 2); fights d4 square and coordinates with Bc4.) | O-O (Removes king from center immediately; plan's king-safety step, connects rooks for central pressure after d4 resolved.)
    • 7. Verify0 tok · 0ms

      Alle 3 Kandidaten legal. cloud_eval disabled (default).

      • chess.js.legal_recheck0ms
    • 8. Reflect2374 tok · 44261ms · claude-sonnet-4-6 · $0.0356

      Final pick: Nxd4 — Eliminates the d4-pawn that threatens dxc3 winning Nc3 for a pawn — a forced material loss if ignored. Restores e4–d4 central grip (heuristic 1) and places the knight on an active central post.. Reject…

      • llm.reflect44261ms · $0.0356
      full reasoning
      Final pick: Nxd4 — Eliminates the d4-pawn that threatens dxc3 winning Nc3 for a pawn — a forced material loss if ignored. Restores e4–d4 central grip (heuristic 1) and places the knight on an active central post.. Rejected: c1e3, e1g1.
    • 9. Commit0 tok · 0ms

      Commit Nxd4 (f3d4).

  12. 12...Bc5Sonnet8.195 tok · $0.1227 · 196800ms
    • 1. Observe0 tok · 0ms

      Halbzug 12, Schwarz am Zug. Phase: Eroeffnung. Material gleich. Legale Zuege: 34. Criticality: 0.30.

      • material-counter0ms
    • 2. Recall Position0 tok · 0ms · skipped

      recall_position disabled for this agent (tool_config.memory_recall=false).

    • 3. Recall Opponent0 tok · 0ms · skipped

      recall_opponent disabled for this agent (tool_config.memory_recall=false).

    • 4. Research0 tok · 354ms

      Web search returned no SearXNG results (empty).

      • web_search.searxng354ms · fail
    • 5. Plan4919 tok · 115268ms · claude-sonnet-4-6 · $0.0737

      Phase: opening. Develop Bf8 actively (Bc5 or Bb4) to contest Bc4's diagonal pressure and deny White the f7 target. Follow with king-safety castling kingside. If Bc5 route, prepare to exchange or retreat the bishop on d4-…

      • llm.plan115268ms · $0.0737
      full reasoning
      Phase: opening. Develop Bf8 actively (Bc5 or Bb4) to contest Bc4's diagonal pressure and deny White the f7 target. Follow with king-safety castling kingside. If Bc5 route, prepare to exchange or retreat the bishop on d4-knight trade. Avoid passive ...Be7 which cedes diagonal initiative entirely. Neutralize the Bc4 bishop's dominance on a2-g8, castle to safety, then convert Sicilian asymmetry into active counterplay via semi-open c-file pressure and queenside b5-b4 pawn advance to dislodge Nd4. Critical: f7 weakness: Bc4+Nd4 combination enables Nxc6/Ndb5 fork/pin threats if Black delays bishop development; Nd4 jump to b5 or f5 becomes powerful if Black castles without challenging Bc4 first; own weakness: Bc8 is completely undeveloped and blocked by e6 — queenside initiative delayed; Nxc6 pawn-doubling threat if Black plays ...Bb4 without precise follow-up.
    • 6. Candidates822 tok · 18917ms · claude-sonnet-4-6 · $0.0123

      Candidates: Bc5 (Primary plan move: contests Bc4's diagonal, denies f7 target, prepares rapid kingside castling.) | Bb4 (Pins Nc3, challenges White's bishop diagonal influence, creates immediate tension per plan.) | Nxd4…

      • chess.js.legal_moves0ms
      • llm.candidates18915ms · $0.0123
      full reasoning
      Candidates: Bc5 (Primary plan move: contests Bc4's diagonal, denies f7 target, prepares rapid kingside castling.) | Bb4 (Pins Nc3, challenges White's bishop diagonal influence, creates immediate tension per plan.) | Nxd4 (Removes dangerous Nd4 jump to b5/f5, simplifies center; plan notes this as precise follow-up.)
    • 7. Verify0 tok · 1ms

      Alle 3 Kandidaten legal. cloud_eval disabled (default).

      • chess.js.legal_recheck0ms
    • 8. Reflect2454 tok · 62248ms · claude-sonnet-4-6 · $0.0367

      Final pick: Bc5 — Bc5 directly contests Bc4 on the a2-g8 diagonal, neutralizing the f7-battery threat. Theory on the Sozin Attack confirms this as the mainline equalizer — bishop lands actively, kingside castling follows…

      • llm.reflect62248ms · $0.0367
      full reasoning
      Final pick: Bc5 — Bc5 directly contests Bc4 on the a2-g8 diagonal, neutralizing the f7-battery threat. Theory on the Sozin Attack confirms this as the mainline equalizer — bishop lands actively, kingside castling follows immediately, and White's Nd4 can no longer jump to b5/f5 without the diagonal being contested.. Rejected: f8b4, c6d4.
    • 9. Commit0 tok · 0ms

      Commit Bc5 (f8c5).

  13. 13.O-OSonnet7.464 tok · $0.1119 · 154789ms
    • 1. Observe0 tok · 0ms

      Halbzug 13, Weiss am Zug. Phase: Eroeffnung. Material gleich. Legale Zuege: 49. Criticality: 0.40.

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

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

      • nex_search15ms
    • 3. Recall Opponent0 tok · 3ms

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

      • nex_entity_search3ms
    • 4. Research0 tok · 0ms · skipped

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

    • 5. Plan2650 tok · 53303ms · claude-sonnet-4-6 · $0.0397

      Phase: opening. Castle kingside at once to remove the king from the e-file, then activate Bc1 to e3 (challenging Bc5 and securing d4) or f4, while keeping Nd4 central and Bc4 trained on the f7–d5 diagonal. If Black excha…

      • llm.plan53303ms · $0.0397
      full reasoning
      Phase: opening. Castle kingside at once to remove the king from the e-file, then activate Bc1 to e3 (challenging Bc5 and securing d4) or f4, while keeping Nd4 central and Bc4 trained on the f7–d5 diagonal. If Black exchanges on d4, recapture to maintain a pawn or piece presence in the center. Leverage the Nd4–Bc4 battery against Black's uncastled king: after O-O and Be3, coordinate a queenside pawn push (c3–d4) or a kingside expansion (f4–f5) depending on whether Black castles or keeps the king in the center. Critical: Black can play ...Nxd4 immediately, dissolving White's dominant d4 knight — must be prepared to recapture favorably (cxd4 opens the c-file; Qxd4 centralizes the queen but invites ...Nc6–e5); Black can answer ...d5 next turn, counterattacking e4 and deflecting Bc4 — heuristic 'central control' reminds us e4 must stay defended before that threat matures; White king on e1 is the biggest liability; heuristic 'knights before bishops' is already satisfied, so the priority now shifts fully to O-O before any tactical skirmish on d4 or f7.
    • 6. Candidates4593 tok · 88411ms · claude-sonnet-4-6 · $0.0689

      Candidates: O-O (Plan explicitly flags White king on e1 as the biggest liability; castle before any d4/f7 tactical skirmish.) | Be3 (Challenges Bc5, secures Nd4, activates Bc1 per plan's Nd4-Bc4-Be3 battery setup.) | Bxe…

      • chess.js.legal_moves0ms
      • llm.candidates88403ms · $0.0689
      full reasoning
      Candidates: O-O (Plan explicitly flags White king on e1 as the biggest liability; castle before any d4/f7 tactical skirmish.) | Be3 (Challenges Bc5, secures Nd4, activates Bc1 per plan's Nd4-Bc4-Be3 battery setup.) | Bxe6 (Heuristic-suggested shot exploiting Black's uncastled king; damages pawn structure and opens lines.)
    • 7. Verify0 tok · 1ms

      Alle 3 Kandidaten legal. cloud_eval disabled (default).

      • chess.js.legal_recheck0ms
    • 8. Reflect221 tok · 13041ms · claude-sonnet-4-6 · $0.0033

      Final pick: O-O — Plan explicitly names the uncastled king as White's biggest liability and mandates O-O before any d4/f7 tactical skirmish. Castling removes the e1 vulnerability and prepares Be3 or f4 safely next.. Reje…

      • llm.reflect13041ms · $0.0033
      full reasoning
      Final pick: O-O — Plan explicitly names the uncastled king as White's biggest liability and mandates O-O before any d4/f7 tactical skirmish. Castling removes the e1 vulnerability and prepares Be3 or f4 safely next.. Rejected: c1e3, c4e6.
    • 9. Commit0 tok · 0ms

      Commit O-O (e1g1).

  14. 14...O-OSonnet7.421 tok · $0.1112 · 159507ms
    • 1. Observe0 tok · 0ms

      Halbzug 14, Schwarz am Zug. Phase: Eroeffnung. Material gleich. Legale Zuege: 39. Criticality: 0.40.

      • material-counter0ms
    • 2. Recall Position0 tok · 0ms · skipped

      recall_position disabled for this agent (tool_config.memory_recall=false).

    • 3. Recall Opponent0 tok · 0ms · skipped

      recall_opponent disabled for this agent (tool_config.memory_recall=false).

    • 4. Research0 tok · 517ms

      Web search returned no SearXNG results (empty).

      • web_search.searxng517ms · fail
    • 5. Plan4113 tok · 81624ms · claude-sonnet-4-6 · $0.0617

      Phase: opening. Resolve the king-safety deficit by castling kingside immediately — this is the single most urgent structural demand. Then push the d-pawn one square forward to shore up the center, blunt the d4-knight's s…

      • llm.plan81624ms · $0.0617
      full reasoning
      Phase: opening. Resolve the king-safety deficit by castling kingside immediately — this is the single most urgent structural demand. Then push the d-pawn one square forward to shore up the center, blunt the d4-knight's scope, and prevent a dangerous knight intrusion toward b5. Follow with queenside prophylaxis via the a-pawn to claim space and prepare the b-pawn thrust that challenges the c4-bishop. Secure the king first, then convert Sicilian asymmetry into active queenside counterplay via the b-pawn advance and semi-open c-file pressure, neutralizing White's central and diagonal dominance before it crystallizes into a kingside attack. Critical: Knight intrusion threat: Nd4 can reroute toward b5, targeting d6 and forking maneuvers — d-pawn advance and a-pawn prophylaxis must preempt this; Dual f7 pressure: Bc4 and Nd4 combine to target f7 — uncastled king is the root vulnerability, castling dissolves this immediately; Nxc6 pawn-structure disruption: White may trade on c6 to double Black's pawns — recapturing with the d-pawn is acceptable and maintains central grip.
    • 6. Candidates704 tok · 14972ms · claude-sonnet-4-6 · $0.0105

      Candidates: O-O (Dissolves Bc4+Nd4 dual f7 pressure immediately; plan demands king safety as single most urgent structural step.) | d6 (Shores up center, blunts Nd4's scope, prevents dangerous knight reroute to b5 target…

      • chess.js.legal_moves0ms
      • llm.candidates14969ms · $0.0105
      full reasoning
      Candidates: O-O (Dissolves Bc4+Nd4 dual f7 pressure immediately; plan demands king safety as single most urgent structural step.) | d6 (Shores up center, blunts Nd4's scope, prevents dangerous knight reroute to b5 targeting d6.) | a6 (Queenside prophylaxis per plan; prevents Nb5 intrusion and prepares b-pawn thrust for counterplay.)
    • 7. Verify0 tok · 0ms

      Alle 3 Kandidaten legal. cloud_eval disabled (default).

      • chess.js.legal_recheck0ms
    • 8. Reflect2604 tok · 62369ms · claude-sonnet-4-6 · $0.0390

      Final pick: O-O — Bc4+Nd4 dual f7 pressure (Sozin B57 theory) is neutralized immediately; Rf8 defends f7, king escapes e-file, connecting rooks — removes the single most urgent structural vulnerability before pursuing qu…

      • llm.reflect62369ms · $0.0390
      full reasoning
      Final pick: O-O — Bc4+Nd4 dual f7 pressure (Sozin B57 theory) is neutralized immediately; Rf8 defends f7, king escapes e-file, connecting rooks — removes the single most urgent structural vulnerability before pursuing queenside counterplay.. Rejected: d7d6, a7a6.
    • 9. Commit0 tok · 0ms

      Commit O-O (e8g8).

  15. 15.Be3Sonnet3.641 tok · $0.0545 · 84126ms
    • 1. Observe0 tok · 0ms

      Halbzug 15, Weiss am Zug. Phase: Eroeffnung. Material gleich. Legale Zuege: 45. Criticality: 0.40.

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

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

      • nex_search12ms
    • 3. Recall Opponent0 tok · 3ms

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

      • nex_entity_search3ms
    • 4. Research0 tok · 0ms · skipped

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

    • 5. Plan2523 tok · 46301ms · claude-sonnet-4-6 · $0.0378

      Phase: opening. Activate the undeveloped Bc1 — per the 'knights before bishops' heuristic, all knights are placed; the bishop is the last lagging piece. Play it to e3 to challenge Black's active bishop, reinforce the d4 …

      • llm.plan46301ms · $0.0378
      full reasoning
      Phase: opening. Activate the undeveloped Bc1 — per the 'knights before bishops' heuristic, all knights are placed; the bishop is the last lagging piece. Play it to e3 to challenge Black's active bishop, reinforce the d4 outpost, and complete development. If Black exchanges on d4, recapture to keep central piece presence (supporting the 'central control' heuristic). Then decide between f4-f5 kingside expansion and d3 consolidation. Exploit the Nd4-Bc4 battery by anchoring the d4 outpost with Be3 and pushing f4-f5 to generate direct kingside pressure against Black's castled king before Black can equalise with a timely d5 break. Critical: Black knight exchange on d4 dissolves White's dominant outpost — recapture choice (Bxd4 vs cxd4) determines middlegame pawn structure; Black's d5 counter-break must be pre-empted; solidifying e4 and d4 with Be3 closes that window; Black's Bc5 may retreat to b6 if challenged — acceptable as it loses a tempo, but White should not delay Be3.
    • 6. Candidates260 tok · 10410ms · claude-sonnet-4-6 · $0.0039

      Candidates: Be3 (Activates last undeveloped piece, challenges Bc5, reinforces d4 outpost — completing development per 'knights before bishops' sequence.) | f4 (Launches kingside expansion, supports e4-e5 push, generates …

      • chess.js.legal_moves0ms
      • llm.candidates10406ms · $0.0039
      full reasoning
      Candidates: Be3 (Activates last undeveloped piece, challenges Bc5, reinforces d4 outpost — completing development per 'knights before bishops' sequence.) | f4 (Launches kingside expansion, supports e4-e5 push, generates direct pressure before Black achieves d5 counter-break.) | Nxc6 (Damages Black's pawn structure, eliminates knight defending d5, opens b-file for rook — forcing Black to recapture and lose central control.)
    • 7. Verify0 tok · 0ms

      Alle 3 Kandidaten legal. cloud_eval disabled (default).

      • chess.js.legal_recheck0ms
    • 8. Reflect858 tok · 27377ms · claude-sonnet-4-6 · $0.0128

      Final pick: Be3 — Completes development of the last lagging piece, directly challenges Bc5 (forcing Black to decide its fate), and cements the Nd4 outpost — closing the window for Black's ...d5 counter-break before expan…

      • llm.reflect27377ms · $0.0128
      full reasoning
      Final pick: Be3 — Completes development of the last lagging piece, directly challenges Bc5 (forcing Black to decide its fate), and cements the Nd4 outpost — closing the window for Black's ...d5 counter-break before expansion.. Rejected: f2f4, d4c6.
    • 9. Commit0 tok · 0ms

      Commit Be3 (c1e3).

  16. 16...Nxd4Sonnet4.887 tok · $0.0732 · 211828ms
    • 1. Observe0 tok · 1ms

      Halbzug 16, Schwarz am Zug. Phase: Mittelspiel. Material gleich. Legale Zuege: 36. Criticality: 0.25.

      • material-counter0ms
    • 2. Recall Position0 tok · 0ms · skipped

      recall_position disabled for this agent (tool_config.memory_recall=false).

    • 3. Recall Opponent0 tok · 0ms · skipped

      recall_opponent disabled for this agent (tool_config.memory_recall=false).

    • 4. Research293 tok · 12150ms · claude-sonnet-4-6 · $0.0044

      Web search (middlegame, SearXNG + summary): This is the Classical Giuoco Piano / Italian Game middlegame, with Black's bishop on c5 facing White's bishop on c4 — a symmetrical bishop duel characteristic of the Four Knigh…

      • web_search.searxng715ms
      • llm.research_summary11435ms · $0.0044
      full reasoning
      Web search (middlegame, SearXNG + summary): This is the Classical Giuoco Piano / Italian Game middlegame, with Black's bishop on c5 facing White's bishop on c4 — a symmetrical bishop duel characteristic of the Four Knights or Classical Italian setup. White has a strong knight on d4 a…
    • 5. Plan1469 tok · 29271ms · claude-sonnet-4-6 · $0.0220

      Phase: middlegame. Challenge White's dominant Nd4 before it consolidates via Nxc6 or Ndb5. Either exchange the knight (Nxd4) to reduce pressure, or strike with the d-pawn to claim central space. Unblock the c8-bishop and…

      • llm.plan29271ms · $0.0220
      full reasoning
      Phase: middlegame. Challenge White's dominant Nd4 before it consolidates via Nxc6 or Ndb5. Either exchange the knight (Nxd4) to reduce pressure, or strike with the d-pawn to claim central space. Unblock the c8-bishop and activate both rooks via the semi-open c-file within 3–5 moves. Neutralize White's bishop pair and Nd4 grip on the center through active piece play and a timely central pawn break, converting Black's solid pawn structure and well-placed Bc5 into queenside counterplay along the c-file. Critical: White's Nd4 threatens Nxc6 (doubling pawns) and Ndb5 invasions — must be challenged immediately; White's Bc4 keeps pressure on f7 and the a2–g8 diagonal — Bb6 retreat may be needed to remove this tension; Black's c8-bishop is blocked by the d7-pawn — advancing d6 or d5 is necessary to free it; According to the Italian/Giuoco Piano research cited: White aims to consolidate with Bb3 and space-gaining d4–d5 advance — Black must act before White achieves this structure; No immediate king-safety concern, but White's bishop pair gives long-term pressure if Black remains passive.
    • 6. Candidates3125 tok · 50327ms · claude-sonnet-4-6 · $0.0468

      Candidates: Nxd4 (Directly eliminates dominant Nd4, neutralizing Nxc6 and Ndb5 invasion threats per plan's top priority.) | d5 (Central pawn break frees the blocked c8-bishop and challenges White's center before d4-d5 co…

      • chess.js.legal_moves0ms
      • llm.candidates50324ms · $0.0468
      full reasoning
      Candidates: Nxd4 (Directly eliminates dominant Nd4, neutralizing Nxc6 and Ndb5 invasion threats per plan's top priority.) | d5 (Central pawn break frees the blocked c8-bishop and challenges White's center before d4-d5 consolidation.) | Bb6 (Retreats bishop off Bc4's a2-g8 diagonal tension as plan notes, while preserving it for later d5 break.)
    • 7. Verify0 tok · 1ms

      Alle 3 Kandidaten legal. cloud_eval disabled (default).

      • chess.js.legal_recheck0ms
    • 8. Reflect0 tok · 120057ms · err:Claude CLI subprocess timed out after 120000ms

      Final pick: Nxd4 — Directly eliminates dominant Nd4, neutralizing Nxc6 and Ndb5 invasion threats per plan's top priority.. Rejected: d7d5, c5b6. [LLM note: Claude CLI subprocess timed out after 120000ms]

    • 9. Commit0 tok · 0ms

      Commit Nxd4 (c6d4).