The game that plays and important role in the movie is called 'weiqi' by the characters and Zhang Liang explains at the banquet that to play blindfolded one has to remember the current state of the each of the 361 (19x19) possible positions. This however, refers to the version of the game made popular several centuries later. The movie is set in late 3rd century BC, when the game was called 'yi' and was played on 17x17 board.