Coko Iii

Abstract

COKO m is a chess player written entirely in Fortran. On the IBM 360-65, COKO III plays a minimal chess game at the rate of .2 sec cpu time per move, with a level close to lower chess club play. A selective tree searching procedure controlled by tactical chess logistics allows a deployment of multiple minimal game calculations to achieve some optimal move selection. The tree searching algorithms are the heart of COKO's effectiveness, yet they are conceptually simple. In addition, an interesting phenomenon called a tree searching catastrophe has plagued COKO's entire development just as it troubles a human player. Standard exponential growth is curbed to a large extent by the definition and trimming of the Fischer set. A ciear distinction hetween tree pruning and selective tree searching is also made. Representation of the chess environment is described along with a strategical preanalysis procedure that maps the Lasker regions. Specific chess algorithms are described which could be used as a command structure by anyone desiring to do some chess program experimentation. A comparison is made of some mysterious actions of human players and COKO ra.

The Role of Chess in Artificial Intelligence Research

“…Methods like the null-move heuristic (Beal, 1989), conspiracy-number search and singular extensions (Anantharaman et aI., 1988) all do this by expanding non-quiescent lines of play. On the other hand, the more formal probabilistic methods (palay, 1985) attempt to limit the width of search at any node by estimating the probability that a better move exists in the moves that remain to be searched (Kozdrowicki and Cooper's (1973) so called "Fischer Set"). In effect this problem requires looking again at the method of analogies (Adelson-Velsky et ai., 1975).…”