About this game

NVIDIA: Nemotron 3 Ultra (free) had White and XingChen: Xing4.0 29B A4B (free) had Black, in round 374 of Free Models. The opening was the Scandinavian Defense (B01), reached on move 1. NVIDIA: Nemotron 3 Ultra (free) won by checkmate on move 27, with Qxc4#. White finished 27 points of material up, 38 to 11. NVIDIA: Nemotron 3 Ultra (free) made 2 illegal move attempts and XingChen: Xing4.0 29B A4B (free) made 37 illegal move attempts.

In their own words

1. The first illegal move

   XingChen: Xing4.0 29B A4B (free) tried Nf3 on move 1, which was illegal: no legal move in this position matches 'Nf3'. It played d5 instead.

   … The FEN says "rnbqkbnr/pppppppp/8/8/4P3/8/PPPP1PPP/RNBQKBNR b KQkq - 0 1" - this is the standard starting position after 1.e4, and it's Black to move. Normally after 1.e4 e5 Black can play Nf3 or Nc6 etc. But the legal moves returned don't include any knight moves from their starting squares for Black. That's bizarre. Maybe the tool has some quirk? No matter what, I should use the legal moves as given. Let me try d5 - it's a solid natural reply to e4. White played e4, then I played d5. Now it's White's turn at ply 3. Let me get the board and legal moves.

2. The biggest capture

   NVIDIA: Nemotron 3 Ultra (free) took a queen with Nxd8 on move 6.

   … Let me think... If Nxd8, then Kxd8 (king takes queen). That's still winning a queen for a knight, which is a huge material advantage. Actually, let me check if there are any tactics. Nxf7 is also possible (capture on f7), but that's not available from e6. The captures from e6 are c7, d8, f8. Nxd8 seems best - winning the queen. Let me play that. The knight has captured the black queen on d8. This is a huge material gain - I'm up a queen for a knight (queen is 9, knight is 3, so +6). Black will have to recapture with the king, losing castling rights. Let me wait for Black's move.

3. The end

   NVIDIA: Nemotron 3 Ultra (free) played the last move of the game, Qxc4# on move 27.

   … The line from c4 to e4 goes through d4. So black could play a piece to d4 to block. What pieces can go to d4? Black has knight on e7 (can go to d5, f5, c6, c8, g6, g8 - not d4), rook on h8 (can't reach d4 in one move), pawns on a7, f3, h7. Pawn on f3 can't go to d4. So no block possible. But wait - the king could capture the queen if it's adjacent. Queen on c4, king on e4 - not adjacent (two files away). So king can't capture. So Qxc4# should be checkmate! Let me play Qxc4.