indirect ko

A ko where either side or both need to ignore more than one ko threat to win the ko. In the diagram the ko is direct for Black because he can end the ko by capturing two white stones, but for White it is a two step ko. He must first play at A, and then, perhaps after exchanging several ko threats until the size of his opponent's threat become sufficiently small, ignore Black's ko threat to play at B, and then ignore yet another ko threat to win the ko by taking off the black stones. Since Black's ko threats need only be half the size of White's, this type of ko is usually favourable to Black.