Go (圍棋 weiqi in Chinese, 囲碁 igo in Japanese, 바둑 baduk in Korean, common meaning: "encircling game") is a board game for two players that originated in China more than 2,000 years ago. The game is noted for being rich in strategy despite its relatively simple rules.

The two players alternately place black and white markers, called "stones", on the vacant intersections (called "points") of a grid of 19×19 lines (beginners often play on smaller 9×9 and 13×13 boards). The object of the game is to use one's stones to surround a larger portion of the board than the opponent. Once placed on the board, stones can only be moved if they are captured (removed from board). When a game concludes, the controlled points (territory) are counted along with captured stones to determine who has more points. Games may also be won by resignation.

Go originated in ancient China. Archaeological evidence shows that the early game was played on a board with a 17×17 grid, but by the time the game had spread to Korea and Japan, in about the 5th and 7th centuries CE respectively, boards with a 19×19 grid had become standard.