Ten-thousand-year ko

A Ten-thousand-year ko is a special ko-like position that remains unsettled indefinitely or for a prolonged period. Both players postpone resolving it because neither has enough immediate incentive to do so. The position’s timing is governed by strategic convenience rather than an urgent tactical need.

Capturing or answering may be unfavorable, so the players wait while surrounding moves, available ko threats, and the changing value of the board alter the situation. Unlike an ordinary ko, its defining feature is that it can be left unresolved for an exceptionally long time. The name is figurative: it does not mean the ko literally lasts ten thousand years, does not describe a fixed number of stages, and should not be confused with an eternal-ko repetition defined at the rules level.