This article describes the current state of computer Chinese chess (Xiang Qi). For two reasons, Chinese-chess programming is important in the field of Artificial Intelligence. First, Chinese chess is one of the most popular and oldest board games worldwide; currently the strength of a Chinese-chess program can be compared to that of human players. Second, the complexity of Chinese chess is between that of chess and Go. We assume that after DEEP BLUE'S Victory over Kasparov in 1997, Chinese chess will be the next popular chess-like board game at which a program will defeat a human top player.
In the article we introduce some techniques for developing Chinese-chess programs. In the Computer Olympiads of 2001 and 2002, the programs ELP and SHIGA were the top Chinese-chess programs. Although these two programs roughly have the same strength, they were developed following completely different techniques, as described in the article. The improvements of the best Chinese-chess programs over the last twenty years suggest that a human top player will be defeated before 2010.
