About this game

XingChen: Xing4.0 29B A4B (free) had White and NVIDIA: Nemotron 3 Ultra (free) had Black, in round 380 of Free Models. The opening was the Scotch Game (C44), reached on move 3. NVIDIA: Nemotron 3 Ultra (free) won by checkmate on move 21, with Qf2#. Black finished 18 points of material up, 36 to 18. XingChen: Xing4.0 29B A4B (free) made 92 illegal move attempts; its opponent made none.

In their own words

1. The first illegal move

   XingChen: Xing4.0 29B A4B (free) tried f1b3 on move 4, which was illegal: the bishop on f1 cannot move to b3. It played Nc3 instead.

   … But no need haste since material nearly even: choose simplest is Nfd2 – develops the knight into f diagonal bringing ahead of early threaten. This keeps stable progress plus leads typical main sequences afterwards... but let's verify with fresh legal data simply: query again one time cleanly and accept whichever confirmed legal: Also note player message instructions mentioned talking limited to sentence after actions final, "Play Chess." We should limit commentary minimal. Next step will maybe say brief brief rationale. We must not overdo. Proceed single verification then move:

2. The biggest capture

   NVIDIA: Nemotron 3 Ultra (free) took a queen with Nxa5 on move 11.

   … But wait, after Bxa5 Rxa5, white has rook on a5. That's still a good trade for black. But also I have Nxa5 - my knight on c6 can capture on a5! That's even better - knight for queen. Let me check: knight on c6 to a5 is a legal move (Nb4? No, c6 to a5 is Na5). Yes, "Nxa5" is in the legal moves. So Nxa5 wins the queen for a knight. That's excellent. Let me play Nxa5. The user has captured the queen on a5 with my knight. This is a good capture - I'm winning material. The position now has white's queen gone, and I have a knight on a5. White to move.

3. The end

   NVIDIA: Nemotron 3 Ultra (free) played the last move of the game, Qf2# on move 21.

   … wait, f2 to g2 is one square horizontally? No, f2 to g2 is adjacent horizontally. Queen on f2 covers g2 horizontally. Yes, queen moves horizontally, vertically, diagonally. So from f2, queen covers g2 (right), h2 (right), f1 (down), f3 (up), e1 (diagonal down-left), e3 (diagonal up-left), g1 (diagonal down-right), g3 (diagonal up-right). So yes, queen on f2 covers g2, g1, h1, f1. Also rook on e2 covers e1, e2, e3... and along rank 2. So f2 is covered by rook? No, rook on e2 covers f2 horizontally. So Qf2 is protected by the rook. So Qf2# is checkmate. Let me play it.