The game is played on a grid of 19x19 points. The color of a point is black, white, or empty. One player uses black, another white. The start is on the empty grid by black. A black / white point is surrounded if no leaving path reaches empty first after black / white; an empty point is surrounded by black / white if any leaving path reaches black / white first after empty. A move of a player colors an empty point his color, then empties all surrounded points of the opponent's color, then empties all surrounded points of the own color. A pass does not color. The end is two successive passes.
 circled black surrounded by white, triangled /
squared empty surrounded by black / white
 alternation; 17, 19, 20 = pass; 20 ends game and any color change
 moves 1 and 2 include emptying of surrounded black points
 move 2 is prohibited due to repeated grid point colors as before move 1
 black wins by 1 point on each end grid; black / white points are triangled / squared