Solving Nine Men's Morris

In recent years, a number of games have been solved using computers. These include Qubic [Patashnik 80], Connect-4 [Allen 89], [Allis 88] and Go-Moku [Allis 93]. All these games were solved using knowledge-based methods. These methods are successful because all these games have a low “decision complexity” [Allis 90], i.e., the right move is often easy to find. Not all games profit to the same extent. For instance, in Checkers, Chess and Go a multitude of moves often seem fairly equal. Brute-force search is often the most viable means of playing or solving this type of game. This observation is supported by the fact that the best programs for both chess [Hsu 90] and checkers [Schaeffer 92] rely heavily on search.