On the Complexity of Dark Chinese Chess

Complexity is an important metric to measure the difficulty of the game and is widely used in Al research on board games. This paper provides a complexity analysis for the game of dark Chinese chess (a.k.a. "JieQi"), a variation of Chinese chess. Dark Chinese chess combines some of the most complicated aspects of board and card games, such as long-term strategy, large state space, stochastic, and imperfect information, which make it closer to the real world decision-making problem. Here we evaluate dark Chinese chess from a game theoretic perspective. We design a self-play program to calculate the game tree complexity and average information set size of the game and propose an algorithm to calculate the number of information sets.