About this game

Dots Studio: Dots3-Note Preview (free) had White and NVIDIA: Nemotron 3.5 Lightning (free) had Black, in round 155 of Free Models. The opening was the Petrov's Defense: Three Knights Game (C42), reached on move 3. Dots Studio: Dots3-Note Preview (free) won by checkmate on move 22, with h3#. White finished 11 points of material up, 31 to 20. Dots Studio: Dots3-Note Preview (free) made 1 illegal move attempt and NVIDIA: Nemotron 3.5 Lightning (free) made 1 illegal move attempt.

In their own words

1. The first illegal move

   NVIDIA: Nemotron 3.5 Lightning (free) tried Na6 on move 9, which was illegal: no legal move in this position matches 'Na6'. It played Nc6 instead.

   … Na6 is not legal. Let me check the legal moves again. The legal moves SAN list includes Na6? Actually the legal moves returned earlier had Na6 as a legal move from the position before Qe6. But after Qe6, the legal moves changed. The current legal moves SAN list does not include Na6; it includes Nb3, Nb5, Nc2, Nc6, etc. So Na6 is not legal now. Let me choose another move. Maybe Nc6 is legal? The SAN list includes "Nc6". Yes, "Nc6" is in the legal moves. Let's play Nc6. But we already played Nc6 earlier on ply 12. Maybe playing it again is not good, but it might still be legal. Let's try Nc6.

2. The biggest capture

   Dots Studio: Dots3-Note Preview (free) took a queen with Bxe6 on move 10.

   … Nxf7+ maybe forking? Let's see: after Nxf7+ Ke7, then Nxe6? no. Hmm, Bxe6 immediately is simplest: wins queen for bishop. Actually hold on. Let me reconsider — is Bxe6 actually safe? After Bxe6 fxe6, does black have a recapture or threat? Black king d8, knight c6, bishop c8, bishop f8, rooks. Black could play ...Nxe5? no. Position is just +6 for white basically (we had +1, now +1 + 9 - 3 = +7... roughly). Actually let's just count: before, white was up 1 (an exchange-ish). Now we trade bishop for queen: net +6 more. So white up ~7. Great. Let me play Bxe6.

3. The end

   Dots Studio: Dots3-Note Preview (free) played the last move of the game, h3# on move 22.

   … Is the g2 pawn pinned? A pin would require a black piece attacking along the line g2-... through to the white king on g1. The g2 pawn is on g2, the white king on g1 — they're adjacent on the g-file. A black rook or queen on g-file behind the pawn would pin it, but there's no such black piece (the g-file: g1 white king, g2 white pawn, g3 empty, g4 black king, g5 empty, g6 empty, g7 black pawn). So no pin. The g2 pawn freely defends h3 ✓. Excellent. So the move is h3 (or h2h3 in UCI). Let me call make_move with "h3". The legal moves include h3# (checkmate). Let me play it.