Go is a four thousand year old board game, invented in China, arguably brought to its highest level by the Japanese. Some have called it Chinese Chess, however this is a poor simplification of the game. In times past, Emperors endowed Universities to study and teach The Art of Go.
In essence, players attempt to stake out, defend, and amass greater territory than can their opponents. The moves in Go consist of placing playing pieces on the intersections of crosshatched, perpendicular lines laid out on a board in a grid pattern. Once placed, the pieces remain until either captured or the game ends. The individual pieces are used to build geometrical patterns deliminating occupied territory. The moves in Go are very simple and can be learned in a short time. The strategy and tactics involved may take a lifetime to master.
Go has a sophisticated handicapping scheme allowing a Dan, or master, to play a student on relatively equal footing.
CGoban is one implementation of a Go client which can connect over the Internet to Go servers, where can be found potential players, and 'bots which will play archived games, from which the student can watch and learn.