The game is played on a 19x19 grid board. The players alternately play on empty board points with black starting. The winner is the player with a higher territory count at the game end if the game does not end before without counting due to loss by resignation or exceeded time. A komi game uses 5.5 points, handicap games use Japanese style. A move surrounding opponent's stones removes them.
Removed stones become prisoners.
A move is forbidden if even after removal of opponent's stones own stones are surrounded. A ko is a shape in which both players can alternately capture one stone. A stone that has captured a stone in a ko may not be recaptured immediately. At the game end stones are alive if a wise player could not see alternating play leading to removal. Living stones of both colours are in seki if a wise player could not see alternating play leading to life of the stones of one colour independently of the stones of the other colour.