Go (game)
The playing pieces are called "stones". One player uses the white stones and the other, black. The players take turns placing the stones on the vacant intersections ("points") of a board. Once placed on the board, stones may not be moved, but stones are removed from the board if "captured". Capture happens when a stone or group of stones is surrounded by opposing stones on all orthogonally-adjacent points. The game proceeds until neither player wishes to make another move. When a game concludes, the winner is determined by counting each player's surrounded territory along with captured stones and komi (points added to the score of the player with the white stones as compensation for playing second). Games may also be terminated by resignation. A teacher might simplify the explanation by saying to a student "you may place your stone on any point on the board, but if I surround that stone, I will remove it."
History of Go
In 1954 a complete Go board made out of stone was found in a tomb dating to the Eastern Han dynasty (25–220) in Wangdu County, Hebei Province. This board has a 17 × 17 grid, which confirms the statement by the 3rd century author Handan Chun in the "Classic of Arts" that Go was at this time played on a 17 × 17 grid:
The go board has 17 lines along its length and breadth, making 289 points in all. The black and white stones each number 150.
The earliest board with a 19 × 19 grid to have been found is a ceramic board dating to the Sui dynasty (581-618) that was excavated from Anyang in Henan Province, so sometime between the 3rd and 6th centuries a change in grid size must have taken place. However, the 17 × 17 board has survived in the version of Go played in Tibet.