Oleksandr Bortnyk: 20...b5? (blitz, 2026-07-11)

Deep puzzles: what the analysis missed

8 手

Oleksandr Bortnyk to move, Black. Lichess's analysis gave the move played no mark (-0.63 before, -0.41 after). A 20-million-node search calls it a blunder, 21 win-chance points against a best move that is unique. Find it before opening the sideline.

The game move. Lichess: -0.63 to -0.41, no label. At 20M nodes: blunder, 19.7 win% given up, 21 points worse than Bxe4.