About this game

NVIDIA: Nemotron 3 Ultra (free) had White and LiquidAI: LFM2.5-2.6B (free) had Black, in round 141 of Free Models. The opening was the King's Knight Opening (C40), reached on move 2. NVIDIA: Nemotron 3 Ultra (free) won by checkmate on move 18, with Bxf7#. White finished 10 points of material up, 33 to 23. LiquidAI: LFM2.5-2.6B (free) made 6 illegal move attempts; its opponent made none.

In their own words

1. The first illegal move

   LiquidAI: LFM2.5-2.6B (free) tried Nf3 on move 2, which was illegal: no legal move in this position matches 'Nf3'. It played Bb4 instead.

   … This seems like a solid choice. Actually, looking at the list again, I notice that the knight moves (Na6, Nc6, Ne7, Nf6, Nh6) are all from b1. And the bishop moves (Ba3, Bb4, Bc5, Bd6) are also from b1. The king moves (Be7, Ke7) and queen moves aren't listed here. Given that Nf3 wasn't available, Bb4 seems like a very natural choice - it's a sharp counter to 1.e5, part of the Szin/King's Indian Defense lines or similar. It develops the bishop and puts pressure on the e5 pawn. Let me go with Bb4.

2. The biggest capture

   NVIDIA: Nemotron 3 Ultra (free) took a queen with Qxc7 on move 17.

   … Bxc7? Bishop on a6 to c7? Not diagonal. Nxc7? Knight on c6 to c7? Not a knight move. Rc8? Rook on a8 to c8? But that's not capturing. The only piece that could recapture on c7 is... none immediately. So White wins a queen for free. But wait - is the white queen on d7 protected? If White plays Qxc7, the white queen goes to c7. Then Black could play... Rxc7? Rook on a8 to c7? a8 to c7 is not a straight line. a8 to c8 is horizontal, but c7 is one down. So no. What about ...b6? Pawn on a7? a7 pawn could take on b6? Not relevant. So Qxc7 seems winning. Let me play it.

3. The end

   NVIDIA: Nemotron 3 Ultra (free) played the last move of the game, Bxf7# on move 18.

   … Attacked? Queen on c7 to g7 horizontally: c7-d7-e7-f7-g7. But f7 has pawn. So not directly. Bishop on c5: c5-d6-e7-f8-g7? No. Bishop on b3: b3-c4-d5-e6-f7-g6-h5, not g7. Rook on e1: e1-e7-g7? No. Knight on f3: f3-g5-h7 or f3-e5-g6 or f3-d4-f5 etc. Not g7 directly. But if king goes to g7, maybe not checkmate immediately but still winning. - g8: empty? Rank 8: g8 empty. Attacked? Similar. Actually, Bxf7# and Qxf7# are both marked as checkmate. So I should play one of them and win the game! Let me play Bxf7# since it's a nice bishop mate. Or Qxf7#. Either works. I'll play Bxf7#.