Adaptive Null-Move Pruning

General wisdom deems strong chess programs to be brute-force searchers that explore game trees as exhaustively as possible within the given time limits. We review the results of the latest World Computer-Chess Championships and show how grossly wrong this notion actually is. The typical brute-force searchers lost their dominance of the field around 1990 when the null move became popular in microcomputer practice. Today, nearly all world-class chess programs apply various selective forward-pruning schemes with overwhelming success.