Let's Play Mahjong!

In the past decades, we have seen AI programs that can beat best human players in perfect information games including checker, chess and Go, where players know everything occurred in the game before making a decision. Imperfect information games are more challenging. Very recently, important progress has been made in solving the two-player heads-up limit Texas hold'em poker [2] and its no-limit version [3], which are the smallest variants of poker played competitively by humans. In this paper, we initiate a mathematical and AI study of the more popular and more complicated Mahjong game. Mahjong is a very popular tile-based multiplayer game played worldwide.