Wei-chi is a Chinese game of strategy for 2 players that dates back about 3000 years. Wei-chi (aka "Go") is played on a square grid of lines with round black and white stones. The standard board size is 19x19 lines, with some markings that don't affect play. (Smaller board sizes are used with the same rules for teaching and for illustrating the game with cut-down examples.)
A game of wei-chi is often compared with 2 armies settling in an unpopulated area. Although capture is important, the main aim is to end up in possession of more territory - not to wipe out the opponent.
Wei-chi can be seen as coming from the same general background as the I-Ching of divination in a purely combinatorial style. What makes a major difference when playing wei-chi is that the feel of the game is not combinatorial, but conceptual. Military theory, in China from Sun Tzu onwards, or based on The Five Rings for the Japanese, both illuminate and may be illustrated by wei-chi. "Strengthen to the left if you want to attack on the right" isn't a paradox on the Wei-Chi board but a commonplace theory.
The ancient Chinese considered the wei-chi board to be a microcosm of the universe. Although, when it is empty, it appears to be simple and ordered, the possibilities of game-play are endless. They say that no two wei-chi games have ever been alike - just like snowflakes. So the wei-chi board actually represents and extremely complex and chaotic universe.
Playing wei-chi teaches you to anticipate, manipulate and control your opponent. It teaches you how to fake, defend, attack and counter. It teaches you how to move around your opponent, when to go in straight and when to move in a circle. Wei-chi is beautifully simple (you can learn to play in about 5minutes - try it!!) yet maddeningly complex (it takes a lifetime to master). I would recommend this game to any serious martial artist wishing to refine their strategy.