Search and Knowledge in Lines of Action

Abstract

This paper describes the design and development of two world-class Lines of Action game-playing programs: YL, a three time Computer Olympiad gold-medal winner, and Mona, which has dominated international e-mail correspondence play. The underlying design philosophy of the two programs is very different: the former emphasizes fast and efficient search, whereas the latter focuses on a sophisticated but relatively slow evaluation of each board position. In addition to providing a technical description of each program, we explore some long-standing questions on the trade-offs between search and knowledge. These experimental results confirm the conclusions made by earlier researchers in the domain of chess, thus showing that the trends are not game-specific. In particular, we see diminishing returns with additional search depth, and observe that the knowledge level of a program has a significant impact on the results of such experiments.KeywordsLines of Actionsearchknowledge