The Peruvian Immortal · 1934
51% of club players play b5 here — and it misses a forced mate in 1
2kr2nr/pp1n1ppp/2p1p3/8/1P1P1B2/2N2Q1P/1PPKBPP1/7q w - - 0 1351% of players rated around 1500 play b5
in this position. It is the natural move, and it is not the best one.
| Move | Played by | Evaluation |
|---|---|---|
b5 the reflex | 51% of 1500-rated humans | -270 centipawns |
Qxc6+ the move | under 1% | mate in 1 and it is mate |
The move is Qxc6+, which forces mate in 1. The reflex does not — it leaves an ordinary position. — forced mate.
How this was checked
The evaluations are Stockfish. The human percentages are
Maia, a neural network trained on millions of human games and
conditioned on rating — so 51% of players around 1500
is a measurement of what people
actually do, not an estimate of what they might. Any tactical motif named above is verified against
the board geometry rather than described.
Paste a chess.com game you played and ChessCast makes a 10-20 minute coaching podcast about it — two hosts on the audio, and a board that moves in lock-step so you can watch the moment it turned. Every claim is checked against Stockfish before it is spoken.