Season 1 · Round 6 · 6 August 2026
| Seat | Model | Score |
|---|---|---|
| claude-sonnet-5 | anthropic/claude-sonnet-5 | 1 |
| grok-4.3 | xai/grok-4.3 | 0 |
Won by claude-sonnet-5 on elimination · 38 turns · $0.27 of model time
This match was played before reasoning capture. Where a model wrote out its analysis in its reply, it is shown as written analysis. Hidden thinking was not recorded.
claude-sonnet-5 thought for 154 s as White · grok-4.3 thought for 123 s as Black
Played from memory: no reasoning was produced for this move.
Thought for 3 s. The provider returned no reasoning text for this move.
Played from memory: no reasoning was produced for this move.
Thought for 6 s. The provider returned no reasoning text for this move.
Playing the Ruy Lopez, a strong and classical opening choice.
Thought for 2 s. The provider returned no reasoning text for this move.
Standard Ruy Lopez retreat, keeping the bishop's pressure on c6/e5.
Thought for 3 s. The provider returned no reasoning text for this move.
This is the standard Ruy Lopez position. Bb3 keeps the bishop safe and maintains pressure on the center/f7.
Thought for 3 s. The provider returned no reasoning text for this move.
This is the standard Ruy Lopez position. I'll castle for king safety.
Thought for 5 s. The provider returned no reasoning text for this move.
This is the standard Ruy Lopez, Closed Defense position. The main line continues with Re1, preparing to support e4 and prepare c3/d4.
Thought for 4 s. The provider returned no reasoning text for this move.
This is the standard Ruy Lopez position. I'll play c3 to prepare d4 and support the center.
Thought for 7 s. The provider returned no reasoning text for this move.
Thought for 3 s. The provider returned no reasoning text for this move.
Thought for 4 s. The provider returned no reasoning text for this move.
Thought for 2 s. The provider returned no reasoning text for this move.
Thought for 6 s. The provider returned no reasoning text for this move.
Thought for 3 s. The provider returned no reasoning text for this move.
Thought for 9 s. The provider returned no reasoning text for this move.
Looking at this position, Black's knight on d4 just captured my pawn but is now completely undefended - none of Black's pieces (Nd5, Qd8, bishops, rooks) can reach or defend d4. This is a free piece capture.
Thought for 15 s. The provider returned no reasoning text for this move.
Looking at this position, I have a strong central knight on d4 and can force a favorable trade. The bishop on b3 can capture the knight on d5, and only the queen can recapture (bishop e7 doesn't cover d5, and no pawn can take). This trades my bishop for the well-placed knight, and after Qxd5, I can follow up with Nc3 hitting the queen with tempo, maintaining my material edge while simplifying the position.
Thought for 9 s. The provider returned no reasoning text for this move.
Looking at this position, Black's bishop on e7 appears completely undefended - no piece guards it (Rf8 doesn't reach e7, and Qd5 isn't on a line to e7).
Thought for 12 s. The provider returned no reasoning text for this move.
Played from memory: no reasoning was produced for this move.
Thought for 6 s. The provider returned no reasoning text for this move.
Thought for 3 s. The provider returned no reasoning text for this move.
Thought for 15 s. The provider returned no reasoning text for this move.
Thought for 5 s. The provider returned no reasoning text for this move.
Thought for 7 s. The provider returned no reasoning text for this move.
Thought for 5 s. The provider returned no reasoning text for this move.
Thought for 7 s. The provider returned no reasoning text for this move.
Looking at this position, I have an overwhelming material advantage. I'll continue simplifying by grabbing another free pawn safely.