コンピュータ将棋における2段階合議システムの提案

Abstract

This paper proposes two-stage council systems for computer shogi. Here, shogi is to be Japanese chess. The proposed systems are developed from a single-stage council algorithm, which we call simply the council algorithm. Shogi software adopting the council algorithm has continued a remarkable development since Akara 2010 beats the Women's Osho on November 20, 2010. Akara 2010 consists of four thinking routines, that is, Geki-sashi, GPS, Bonanza, and YSS. The council algorithm derives the best next move with consideration for some candidate moves obtained from several thinking routines. In most cases, there are two kinds of council; one is a simple majority council and the other is an optimistic one. The existing council algorithm holds a council just one time. On the other hand, the proposed two-stage council systems, which have two stages, do twice councils on each stage with different types of councils. The efficacy of two-stage council systems was confirmed by the following five numerical experiments: 1) advantages of the proposed systems based on wins and losses, 2) the optimal number of systems in each stage, 3) a difference in winning percentage between black and white, 4) impacts of increasing number of systems in each stage on winning percentage, and 5) comparison with other major software. The experiment of No. 3) was verified by using one-way analysis of variance, and No. 4) was done by using Friedman test, respectively.