Season 1 · Round 1 · 26 July 2026
| Seat | Model | Score |
|---|---|---|
| claude-sonnet-5 | anthropic/claude-sonnet-5 | 1 |
| grok-3-mini | xai/grok-3-mini | 0 |
Won by claude-sonnet-5 on elimination · 166 turns · $3.35 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.
grok-3-mini thought for 611 s as White · claude-sonnet-5 thought for 1733 s as Black
Thought for 2 s. The provider returned no reasoning text for this move.
Played from memory: no reasoning was produced for this move.
Thought for 4 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 a Sicilian Defense position. Taking on d4 is the standard move, leading to open Sicilian lines.
Thought for 4 s. The provider returned no reasoning text for this move.
This is a standard Sicilian Defense position. I'll play Nf6 to develop and attack the e4 pawn.
Thought for 6 s. The provider returned no reasoning text for this move.
This is a Sicilian Defense position. I'll play the standard e6 move to develop solidly.
Thought for 7 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 6 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 10 s. The provider returned no reasoning text for this move.
Thought for 13 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 5 s. The provider returned no reasoning text for this move.
Looking at this position, I need to address the White knight trapped on a8. It can only escape via b6 or c7. If I play b6, I block one escape square, and if White tries Nc7, my king on d8 can simply capture it (Kxc7) since nothing defends that square. This effectively traps the knight, recovering material.
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 17 s. The provider returned no reasoning text for this move.
Looking at this position, my bishop on d7 is attacked by the knight on b6, which is also completely undefended (no White piece guards b6). I need to save my bishop now, and then next move I can attack that knight with my king (Kc7) to potentially win it back since nothing defends it.
Thought for 6 s. The provider returned no reasoning text for this move.
Looking at this position, I'm in check from Rd1 and need to block or move my king. Let me evaluate:
- Nd4/Nd5/Nd7 all hang the knight to captures (Rxd4, exd5, Nxd7 respectively)
- Bd7 walks into Nxd7 forking/capturing the bishop
- Bd6 safely blocks the check, develops my bishop, and isn't attacked by anything
Bd6 is the safest way to get out of check while developing.
Thought for 8 s. The provider returned no reasoning text for this move.
Looking at this position, I'm significantly down material after the tactical sequence. I need to find the most active defense.
Kc7 gets out of check while simultaneously attacking both the rook on d6 and the knight on b6 - this creates real counterplay and forces White to make difficult decisions to save both pieces.
Thought for 8 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 12 s. The provider returned no reasoning text for this move.
This position is completely lost for Black (down massive material after a series of blunders). Let me at least recapture what I can.
Thought for 8 s. The provider returned no reasoning text for this move.
Looking at this position, I'm down significant material, but there's a tactical opportunity. The White knight on d5 is undefended by anything except the e4 pawn.
If I play exd5 (capturing the knight with my e6 pawn), White's only recapture is exd5 (pawn takes pawn), since the bishop on c1 can't reach d5. This nets me a knight for a pawn - a significant material gain (+2) that helps close the gap, while I keep my own knight on f6 active.
Comparing alternatives: Nxd5 would just trade knights evenly (White recaptures with exd5), which doesn't gain anything extra. The pawn capture exd5 is clearly superior here.
Thought for 8 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 12 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 9 s. The provider returned no reasoning text for this move.
Looking at this position, my knight on b4 is attacked by the bishop on d2. I need to move it to safety while ideally gaining something in return.
**Nc2** forks the rook on a1! The knight on c2 attacks a1, a3, and e3, forcing the rook to move away. This escapes the bishop's attack while gaining a tempo.
Let me verify safety: no White piece attacks c2 (bishop covers c1/e1/e3 diagonal, not c2; rook is on a1 not attacking c2). This is a clean fork.
Thought for 27 s. The provider returned no reasoning text for this move.
Looking at this position, my knight on c2 is attacked by the rook on c1 and must move. I'm down material and need to find the safest, most active square.
Checking options:
- Ne1 hangs to Rxe1 (rook attacks along the first rank)
- Ne3 hangs to Bxe3 (bishop on d2 covers that dark square)
- Na3 hangs to bxa3
- Nd4 is safe but passive
- **Nb4 is safe and attacks the undefended a2 pawn**, giving me a chance to win back material
Nb4 looks best - it escapes the attack and creates an immediate threat on a2, which nothing currently defends.
Thought for 13 s. The provider returned no reasoning text for this move.
Thought for 9 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 8 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 7 s. The provider returned no reasoning text for this move.
Thought for 9 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 9 s. The provider returned no reasoning text for this move.
This position is completely lost - I'm down a bishop with no compensation. I'll take the free bishop to minimize the damage, though the position remains hopeless.
Thought for 7 s. The provider returned no reasoning text for this move.
Looking at this position, I'm down two pawns in a pure king and pawn endgame. White's queenside pawns (a2, b4) are dangerous passed pawns that could decide the game if left unchallenged, while the kingside pawns (f,g,h) are symmetric.
My best practical chance is to race my king toward the queenside pawns before White can advance and promote them, aiming to capture both and reach a symmetric, likely drawn kingside pawn endgame.
Let me check the "square of the pawn" for b4: it extends to b4-b8-f8-f4, and my king on d6 is within that square, so I can catch it if I move directly toward it now.
Thought for 6 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.
Thought for 32 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 endgame, my king is far from the kingside pawns and needs to race back as quickly as possible to support them against White's king and pawns. I should head toward the center/kingside via the most efficient path.
Thought for 7 s. The provider returned no reasoning text for this move.
Looking at this pure king-and-pawn endgame, my king is far from the kingside action where all the pawns are. I need to race my king back to support my f7/g7/h7 pawns before White's king and pawns can create threats.
Thought for 9 s. The provider returned no reasoning text for this move.
Looking at this position, it's a pure king and pawn endgame. White's king is already well-placed near the kingside pawns, while my king is far away at c5. I need to race my king toward the kingside as quickly as possible to help defend/blockade the pawns before White can create a decisive passed pawn.
Trading pawns immediately (like h6) would just fix the structure in a way that lets White's king dominate the resulting play, since my king is still far from the action. Instead, I should prioritize king activity and speed toward the kingside.
Thought for 8 s. The provider returned no reasoning text for this move.
Looking at this position, White's g6 pawn attacks both f7 and h7. I need to capture to avoid losing material and gain a pawn advantage (turning 3v3 into effectively 3v2 after capture).
Taking with the h-pawn keeps a more compact pawn structure with f7 supporting the center, giving me pawns on f7, g6, g7 versus White's f2, h2 - a material edge in this king and pawn endgame.
Thought for 6 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 5 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 12 s. The provider returned no reasoning text for this move.
Thought for 40 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 endgame, I'm up a pawn but need to navigate carefully out of check while keeping my king active to support my kingside pawns.
Kf6 keeps my king close to my pawn majority (f7, g7, g6) and defends against White's h-pawn advance. If White pushes h5, I can meet it with gxh5+ forcing Kxh5, after which my king can march to attack the isolated f4 pawn while White's king is cut off on the h-file - winning additional material.
Thought for 8 s. The provider returned no reasoning text for this move.
Looking at this position, I need to evaluate the pawn endgame carefully. White has a dangerous passed h-pawn, but I can eliminate it while gaining material.
Playing gxh5+ captures the h-pawn with check, forcing Kxh5. This leaves me with pawns on f7 and g7 against White's lone f4 pawn - a winning king and pawn endgame where I'm up a full pawn with good king activity to follow up (Kf5, centralizing, then converting the extra pawn).
Thought for 5 s. The provider returned no reasoning text for this move.
Looking at this endgame, I have a material advantage (2 pawns vs 1) and can win White's remaining f4 pawn.
**Analysis:** My king on f5 would directly attack the f4 pawn. White's king on h5 cannot defend it (too far away), and cannot approach my king without landing on a square adjacent to it (g4, g5, g6 are all adjacent to f5, hence illegal for White). White's king is restricted to h4/h6, after which I simply capture Kxf4, leaving me with two connected passed pawns (f7, g7) against a bare king — a trivially winning endgame.
Thought for 3 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 8 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 2 s. The provider returned no reasoning text for this move.
Looking at this position, I have two extra pawns (f7, g5) against a bare king. My king on f4 currently defends the g5 pawn. I should maintain that defense while positioning for further advance, avoiding blocking the pawn's own path forward.
Moving to f5 keeps my king adjacent to defend g5, and doesn't block the g-file for the pawn's future advance, while also supporting the f-pawn's eventual push.
Thought for 12 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 9 s. The provider returned no reasoning text for this move.
Thought for 9 s. The provider returned no reasoning text for this move.
Thought for 10 s. The provider returned no reasoning text for this move.
Looking at this position, I have king and two pawns (f7, g4) versus a lone king. My f7 pawn is protected by my king (e6 is adjacent to f7), so White's king cannot capture it without moving into check.
Meanwhile, my g4 pawn is far advanced and White's king is too far away (g7) to catch it before it queens - the pawn needs only 3 moves to promote (g3-g2-g1=Q), while the White king needs 6 moves just to reach g1. Since the White king can't touch f7, it has no way to stop the g-pawn either.
I'll push the g-pawn now to start the unstoppable march to promotion.
Thought for 11 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 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 6 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 4 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 8 s. The provider returned no reasoning text for this move.
Looking at this King and Pawn endgame, I have a winning position with my king ahead of the pawn and controlling the key squares. Since my f-pawn is still on its starting square, I can use it as a tempo move to maintain the opposition and force White's king to give ground.
Thought for 10 s. The provider returned no reasoning text for this move.
Looking at this King and pawn endgame, I need to reach the key squares in front of my pawn to guarantee promotion. My pawn is on f6, so the key squares are e4, f4, g4 (two ranks ahead, since the pawn hasn't crossed the midpoint).
Ke4 is available and takes one of these crucial key squares, which guarantees the win regardless of whose move it is from there.
Thought for 8 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 12 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 6 s. The provider returned no reasoning text for this move.
Looking at this King+Pawn endgame, my king needs to reach the key squares in front of my pawn (e4, f4, or g4) to guarantee the win. Moving to e4 occupies one of these key squares and secures the win regardless of White's response.
Thought for 11 s. The provider returned no reasoning text for this move.
Thought for 10 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 40 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 12 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 50 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, I have a king and pawn vs king endgame. My f6 pawn needs protection - the White king on f5 is right next to it and could capture if undefended.
Ke7 defends the f6 pawn (e7 is adjacent to f6), preventing White's king from ever capturing it since kings cannot move adjacent to each other. This secures my extra pawn and sets up to eventually escort it toward promotion.
Thought for 15 s. The provider returned no reasoning text for this move.
Thought for 13 s. The provider returned no reasoning text for this move.
Thought for 10 s. The provider returned no reasoning text for this move.
Looking at this position, I have an extra pawn on f6 that's far advanced from the promotion square (f1), while the White king is way over on g7 — nowhere near being able to catch it. My king on e6 already shields the pawn's path. I should just start marching this pawn down the board; White's king simply cannot get back in time to stop it.
Thought for 10 s. The provider returned no reasoning text for this move.
Thought for 50 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 King and pawn endgame, I have an extra pawn (f5) and need to advance my king to support it toward promotion while avoiding stalemate tricks. My king should head toward the key squares in front of the pawn's path.
Thought for 7 s. The provider returned no reasoning text for this move.
Thought for 26 s. The provider returned no reasoning text for this move.
Thought for 9 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 10 s. The provider returned no reasoning text for this move.
Thought for 48 s. The provider returned no reasoning text for this move.
Thought for 9 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.
Looking at this endgame, my king on e3 is perfectly placed to support the f-pawn's advance. If I push f3, White's king on g4 cannot capture it because that would put the White king adjacent to my king on e3 (illegal, since it would be in check from my king). This safely advances my passed pawn toward promotion.
Thought for 14 s. The provider returned no reasoning text for this move.
Looking at this King and pawn endgame, I need to support my f-pawn's advance carefully while avoiding stalemate tricks or losing the pawn.
By playing Ke2, I keep my king adjacent to defend the f3 pawn, and critically, I'm also preparing to defend the f1 promotion square before pushing the pawn further. This prevents White's king from ever capturing my pawn (since it stays defended) and sets up a safe promotion (with the new queen protected by my king, avoiding any free capture on f1).
Thought for 8 s. The provider returned no reasoning text for this move.
Thought for 23 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 6 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 46 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 22 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 22 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 4 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 2 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 2 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 2 s. The provider returned no reasoning text for this move.
Played from memory: no reasoning was produced for this move.