big eye

A big eye is an eye containing several connected empty points rather than just one. Because it has internal space, filling or removing that space generally takes more than one move. This changes the group’s effective liberty count during a capturing race.

Big eyes help players compare the strength of groups in a capturing race and judge whether a group can make life. Unlike a one-point eye, a big eye has multiple internal points and normally cannot be neutralized in a single move. It does not guarantee life by itself, however: its status depends on the surrounding shape, the group’s liberties, and whether the opponent can play inside the eye.