Searching to Variable Depth in Computer Chess

Abstract

This paper discusses some methods for guiding the search of conventional chess programs to variable depth. The motivation for investigating such methods comes from the fact that searching to a fixed depth causes difficult problems (e.g. the horizon effect). The first section deals with certain improvements of the quiescence search and a demonstration of their beneficial effects. The method of not counting moves as a ply of depth is investigated then and the results of extending it somewhat are reported. As this method seems to be too simple nevertheless, a more general model tor extending the horizon of the full-width search to variable depth is proposed.