1997-02-26 last update, 1996-09-17 first day, Robert Jasiek

The Basic Ko Rules

Introduction : The Basic Ko Rules aim with a short and precise text at easy determination of kos and allowed moves, even if many basic kos are on the board. Between so called ko threats on the board that do not capture stones of kos each player can capture only once in each ko. The Basic Ko Rules are illustrated with examples.

Definition : ko : Two board points are a ko if on them a move of one player followed by a move of the other player repeats the configuration of stones.

basic ko rule : A stone in a ko that has captured a stone in it may not be recaptured immediately.

prohibition rule : From all board positions with the same set of board points of all kos and with the same configuration of stones on the board without the set each player may only once play on each board point.