Go is the (Australian) English name for the ancient oriental game known as weiqi (Chinese), igo (Japanese), or baduk.
The classical form of the game has two players, the stronger player having white stones and the other player having black stones. Each player takes turns either placing a stone on an intersection (and maybe building a group of adjacent stones, or surrounding and capturing an opponent’s group, or surrounding territory which is then worth points) or passing. The game ends when both players pass.
The board is a grid of 19 by 19 ines for regular play in clubs and tournaments; 13 by 13 for quick games or intermediate teaching games, and 9 by 9 for lightning games or little games for beginners.