Futility Pruning at Pre-Frontier Nodes

Our new pruning technique extends on the scheme of selective futility pruning at frontier nodes and combines it with an idea from razoring. Therefore, we call it ``extended'' futility pruning. Extended futility pruning cuts complete branches of non-checking moves at pre-frontier nodes (depth = 2) according to solely static criteria at the respective nodes as formally described below. This is of course theoretically unsound and also slightly riskier than normal futility pruning. However, extensive experiments with our master-strength chess program DARKTHOUGHT show that extended futility pruning works markedly well in practice.


Created by Ernst A. Heinz, Thu Dec 16 23:28:11 EST 1999