Two eyes = life
Two eyes. Tap the black group — surrounded by white, its only liberties are the two empty points it wraps around. Those are its eyes.
An eyeis an empty point completely surrounded by one colour's stones. The magic rule: a group with two separate eyes can never be captured.
Why? To capture, the opponent must fill every liberty. But filling an eye is a move with no liberties of its own — illegal self-capture — unless it takes the group at the same time. With two eyes the attacker would have to fill both at once, and they can only play one stone per turn. So the group lives. Forever.
- One eye is not enough (see the bottom board).
- The two eyes must be separate — one big space can be filled down to nothing.
- Living = making two eyes; killing = stopping your opponent from making them.
Try to kill it.You're White — tap either eye and try to capture the black group.
You can't. Playing inside an eye is rejected as self-capture: your stone would have no liberties, and it doesn't take the black group because the other eye is still a liberty. Two eyes is a permanent, uncapturable shape.
This is the heart of the whole game. Every fight is ultimately about whether a group can make two eyes — or be stopped from doing so.
One eye dies.You're White — tap the single empty point in the middle of the black ring.
With only oneeye, that eye is the group's last liberty — so filling it does capture, and the whole group comes off the board. One eye is a dead shape; two eyes is alive.
That's the difference between a group that survives the game and one that gets scooped up. Next: how those living groups translate into a final score.