igo

Igo is the Japanese name for the board game known internationally as Go. It is a strategy game for two players played on a grid-based board, typically 19x19, though smaller boards such as 9x9 and 13x13 are common for beginners and teaching. The game originated in ancient China more than two thousand years ago under the name Weiqi and spread to Japan and Korea, where it acquired the names igo and baduk respectively.

Players alternate placing stones on the intersections of the grid. Stones do not move once placed, and the objective is to control more territory on the board than the opponent by surrounding empty points and by capturing opponent stones that have no remaining liberties. A stone or connected group is captured when all its liberties are occupied by the opponent. The ko rule prevents endless repetition of the same position, preserving game progress.

The game ends after both players pass in succession. Scoring varies by rule set, but commonly involves counting controlled territory plus captured stones, with komi added to the second player to compensate for going second. Differences among Japanese, Chinese, and Korean rule variants are minor but affect exact counting.

Go has a long tradition of study and competition. A large international community organizes events through bodies such as the International Go Federation and national associations. The game is also widely played online and on computer platforms, and it has been the subject of significant developments in artificial intelligence and machine learning.