Man and machine

The other day, a top computer chess engine demolished the world no. 2 Hikaru Nakamura in a series of online blitz games by a 14-2 margin. Nothing unusual in that; computers have played at superhuman levels for decades now, to the point where scoring two points out of 16 counts as an achievement. But those games were also played with knight odds for Nakamura! His opponent, an online chess-playing bot named ‘LeelaKnightOdds’, has been specially tuned to play with a knight missing from the start position. It was adapted from ‘Leela Chess Zero’ (aka LCZero), an open source project based on the ideas behind the AlphaZero engine described in papers by Google DeepMind in 2017.

    Despite this chasm between man and machine, there remains scope for machines to improve, as shown by the following game. Stockfish, another top engine, evaluated the position below as essentially a certain win for White. And why not? Kingside attack, rook for bishop and pawn, and the h6 pawn is about to fall. Leela was more phlegmatic, so to speak, since it foresaw a beautiful resource. (Stockfish ultimately won this match, so evidently it also has strengths which Leela lacks).

Stockfish–Leela Chess Zero

Classical Cup 4, Match 11, Game 15, April 2025

47…Qxf5!! 48 exf5 Bf6 49 Kc1 Kf8 50 Kd1 Re7 Humans can readily perceive what Stockfish could not. Black has a fortress, as there are no entry points for White’s major pieces. In the next 32 moves, the rooks came to e1 and e4, and the queen came to f3. Leela moves its king to d8 and knight to f8. (Moves omitted.) 83 Rxe5 Rxe5 84 Rxe5 Bxe5 85 f6 Kc7 86 Qf5 Kb7 87 f7 Bg7 88 Qe4 Be5 The rook sacrifice was the only try, but the fortress holds, as all the queen’s entry squares are covered.