Season 1 · Round 5 · 4 August 2026
| Seat | Model | Score |
|---|---|---|
| claude-sonnet-5 | anthropic/claude-sonnet-5 | 0 |
| gemini-3.1-pro-preview | gemini/gemini-3.1-pro-preview | 1 |
Won by gemini-3.1-pro-preview on elimination · 62 turns · $1.71 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 486 s as White · gemini-3.1-pro-preview thought for 453 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 5 s. The provider returned no reasoning text for this move.
This is the classic Sicilian Najdorf-like setup. I'll play the Open Sicilian main line with d4.
Thought for 4 s. The provider returned no reasoning text for this move.
This is standard Sicilian theory - recapture the pawn with the knight.
Thought for 4 s. The provider returned no reasoning text for this move.
This is a standard Sicilian Najdorf-like position. I'll develop with Nc3, a solid main line move.
Thought for 4 s. The provider returned no reasoning text for this move.
This is the classic Najdorf setup. Be2 is a solid developing move preparing castling.
Thought for 6 s. The provider returned no reasoning text for this move.
This is the classic Najdorf-like setup. Nb3 is the standard retreat, keeping the knight flexible and avoiding tactics against the d4 knight.
Thought for 5 s. The provider returned no reasoning text for this move.
Castling for king safety is the priority here.
Thought for 6 s. The provider returned no reasoning text for this move.
This is a standard Sicilian-type position. I'll develop with Be3, preparing to control the center and coordinate my pieces.
Thought for 6 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 18 s. The provider returned no reasoning text for this move.
Thought for 11 s. The provider returned no reasoning text for this move.
Thought for 17 s. The provider returned no reasoning text for this move.
Thought for 27 s. The provider returned no reasoning text for this move.
Thought for 10 s. The provider returned no reasoning text for this move.
Recapture with the queen to regain the piece.
Thought for 10 s. The provider returned no reasoning text for this move.
Thought for 20 s. The provider returned no reasoning text for this move.
Thought for 39 s. The provider returned no reasoning text for this move.
Thought for 17 s. The provider returned no reasoning text for this move.
Thought for 31 s. The provider returned no reasoning text for this move.
Looking at this position, my bishop on e3 is attacked by the f4 pawn. I need to retreat it to a safe square.
Checking the retreat squares:
- Bd4: hangs to exd4
- Bc5: hangs to dxc5
- Bb6: hangs to Nxb6
- Ba7: hangs to Rxa7
- Bc1/Bd2: both safe
I'll choose Bd2, keeping the bishop flexible for future repositioning to c3 or e3 later.
Thought for 37 s. The provider returned no reasoning text for this move.
Thought for 35 s. The provider returned no reasoning text for this move.
Thought for 34 s. The provider returned no reasoning text for this move.
Looking at this position, I notice that Black's rook on a5 is only defended by the queen on d8 (via the d8-a5 diagonal), and I can capture it with my knight.
**Nxa5!** trades my knight for Black's rook (winning the exchange). Black's only recapture is Qxa5, after which material becomes exactly equal (26-26), significantly improving my position from being down material to fully equal, while also displacing Black's queen to a less active square.
Thought for 14 s. The provider returned no reasoning text for this move.
Thought for 33 s. The provider returned no reasoning text for this move.
Thought for 43 s. The provider returned no reasoning text for this move.
Thought for 44 s. The provider returned no reasoning text for this move.
Thought for 8 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 16 s. The provider returned no reasoning text for this move.
Thought for 24 s. The provider returned no reasoning text for this move.
Thought for 14 s. The provider returned no reasoning text for this move.
Thought for 54 s. The provider returned no reasoning text for this move.
Thought for 20 s. The provider returned no reasoning text for this move.
Thought for 14 s. The provider returned no reasoning text for this move.
Thought for 14 s. The provider returned no reasoning text for this move.
Looking at this position, I'm down significant material (queen and bishop for a rook), so I need to fight actively and create complications while consolidating my position.
The d6 pawn is a potential target, and activating my rook to the d-file puts some pressure on Black's position while I look for chances.
Thought for 13 s. The provider returned no reasoning text for this move.
Looking at this position, I'm down significant material (queen+bishop for rook), so I need to play solidly and look for practical chances rather than forcing lines that lose more material.
Rxd6 would lose the rook to Qxd6 (queen on b6 covers the d6 square along the rank), so I should avoid that. Instead, I'll centralize a rook to create some activity and put pressure on Black's position.
Thought for 37 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 18 s. The provider returned no reasoning text for this move.
Thought for 47 s. The provider returned no reasoning text for this move.
Thought for 15 s. The provider returned no reasoning text for this move.
Played from memory: no reasoning was produced for this move.
Thought for 3 s. The provider returned no reasoning text for this move.