Strategies for the Automatic Construction of Opening Books

Abstract

An opening book is an important feature of any game-playing computer program. These books used to be constructed manually by an expert, by storing good moves suggested by theory, or simply by listing all games ever played by strong players [2,5,8]. Interest has recently shifted to automatic opening book construction where positions are selected by a best-first strategy, evaluated using a brute force search and then added to the opening book [3].

This paper presents the new “drop-out expansion” strategy for automatic opening book construction. It generalizes the previously used best-first strategy and reduces the opportunities for the opponent to force the player out of the book. The algorithm was used to calculate opening books for several games, including Awari and Othello, and helped to win the Awari tournament of the Computer Olympiad [10].

Acknowledgments

My thanks go toAlvaro Fussen for letting me use his Othello engine, and to Nora Sleumer for her many helpful comments on earlier versions of this paper.