ko
A ko occurs when the retaking of a single stone would illegally repeat a previous board position. Hence a ko threat is played elsewhere in the anticipation of forcing a reply so that the stone can then be captured legally. This in turn sets up another ko. Under Japanese rules, for counting purposes, unresolved kos are filled at the end of the game. An example of ko for the life of a group is given in the diagram. After White takes, Black is not allowed to immediately retake. If White answers a ko threat made by Black elsewhere on the board, only then can Black retake in the attempt to obtain two eyes. |
|
 |