semeai

A life and death struggle between two or more groups. Except where seki is engineered, one side must die. The marked stones in the diagram are in the midst of such a battle. It is White's turn to play. If he plays a throw-in at A, he can prevail, but if Black should get to play at A first, Black can win.

( Note that if one side has significantly more liberties than the other, the situation is a walkover. Only when the effective liberties are roughly balanced is there a real chance that skilful play can compensate for an inferior position.)