Zhang Qi is an abstract strategy game, in which the players simply take turns claiming a number from the set {2, 5, 7, 10, 11, 14, 15, 17, 20, 23, 25, 31, 33, 37, 39, 40, 44, 46, 49, 50, 53, 59, 60, 61, 62, 68, 71, 73, 74, 78, 79, 83}. What makes the game something other than a trivial exercise is that the person whose turn it is, is always the player with the lower score, which means that getting too far ahead can ultimately set you behind, as your opponent takes several turns in a row. The winner is the player whose claimed numbers have the highest sum.
Because the shape of the board is irrelevant (technically, you could play by grabbing numbered chips from the middle of the table), the designer gave the game some visual appeal by making the board square, with numbered spaces set up like the board was broken into fragments.