Two eyes

Two eyes is a group formation with two distinct true eyes. Since the eyes are separate, a surrounding opponent cannot fill both of them without violating the liberties and capture rules. The group therefore cannot be captured through a direct attack and is unconditionally alive against ordinary capture attempts.

Recognizing two eyes is fundamental in life-and-death reading: it tells you whether a group is alive rather than merely unsettled. Two true eyes provide independent life; an apparent eye that is false, shared, or reducible to one eye does not. This is different from seki, in which a group’s life depends on mutual restrictions between opposing groups. A shape that looks like it has two eyes may still contain a false eye or a tactical defect, so the position must be read rather than judged by appearance alone.