By on •
Introduction
Current computer chess engines include a neat feature: the analysis bar. For example here is the analysis bar from chess.com.
White to move, FEN: rnb2rk1/ppp2ppp/3p1q1n/4p3/7P/b1PPP3/PP1BBPP1/R2QK1NR w KQ – 0 1
The analysis bar is on the left, and the white portion is 74 “centipawn units” below the midpoint (matching the -0.74 “pawn units” in the top right analysis tab). This means the analysis feels white is at a 74 centipawn disadvantage to black in this position. The question is, what is a centipawn advantage?
Lichess gives a similar analysis and score (in this case -50 centipawns).
As probabilities
From the Stockfish Interpretation of the Stockfish evaluation document we have: “a 1.0 pawn advantage being a 0.5 (that is 50%) win probability.” A player with a 100 centipawn advantage is thought to have a 50% chance of winning (probability taken over chess engine near-optimal variations of play). Notice this is not necessarily the traditional material value of a pawn on the board. The intent is given in a reference graph that we reproduce here.
... continue reading