The effects of speed on skilled chess performance.

Two types of mechanisms may underlie chess skill: fast mechanisms, such as recognition, and slow mechanisms, such as search through the space of possible moves and responses. Speed distinguishes these mechanisms, so I examined archival data on blitz chess (5 min for the whole game), in which the opportunities for search are greatly reduced. If variation in fast processes accounts for substantial variation in chess skill, performance in blitz chess should correlate highly with a player's overall skill. In addition, restricting search processes should tend to equalize skill difference between players, but this effect should decrease as overall skill level increases. Analyses of three samples of blitz chess tournaments supported both hypotheses. Search is undoubtedly important, but up to 81% of variance in chess skill (measured by rating) was accounted for by how players performed with less than 5% of the normal time available.