Liberties and Capture in Go: How Stones Are Taken

A stone in Go is captured when the last empty point next to it is filled by the opponent. Those empty neighbouring points are called liberties, and counting them is the single most useful habit a new player can build. Everything on this page follows from one idea: a group with liberties is safe for now, a group with one liberty is in danger this turn, and a group with none is already off the board.

This goes deeper into capture than the rules of Go does. If you have not read the basic rules yet, start there, or work through the interactive tutorial where the board checks your moves for you.

What a liberty is

A liberty is an empty point directly next to a stone, connected along a line. Up, down, left and right count. Diagonals do not. How many a stone has depends only on where it sits.

Three black stones on a small board with their liberties marked: the stone in open space has four marked points around it, the stone on the left edge has three, and the stone in the bottom-right corner has two.
Four liberties in the open, three on an edge, two in a corner. The edge does the opponent's work for them.

That is why corners and edges are dangerous places to leave a lone stone, and also why they are cheap places to build territory. A stone in the corner needs only two opponent stones to capture it. A stone in the middle needs four.

Groups share their liberties

Stones of the same colour sitting directly next to each other (along the lines, not diagonally) form a group. A group is captured or survives as a single unit, and its liberties are all the empty points around the whole shape.

Two connected black stones in the middle of a board with six empty points marked around them, showing the liberties the pair shares.
Two stones apart have four liberties each. Joined, they share six, and all six have to be filled.

Connecting costs you something: the point between the two stones is no longer a liberty. What you get back is that the opponent now has to surround the whole shape before anything comes off. Connected stones are much harder to kill, which is why so many Go decisions come down to connecting or cutting.

Atari: one liberty left

When a stone or group is down to its last liberty, it is in atari. One more opponent stone captures it. Saying “atari” out loud is not required, and in a serious game it is considered rude, but the word is everywhere in Go writing.

A black stone with white stones on three sides and a single empty point left beside it, the position called atari, one move away from capture.
Black is in atari. The marked point is the last liberty.

A group in atari has three ways out. Run, by extending to a point that adds liberties. Connect, by joining a friendly group that has liberties of its own. Counter-attack, by putting one of the surrounding groups in atari first. If none of those work, the fourth option is to let the stones go and take a better move somewhere else, which is often the right answer.

Capture: filling the last liberty

Fill the final liberty and the stones are removed at once, before anything else happens. The points they occupied become empty again, and either player can play there on a later turn.

The same position after white fills the final liberty: the black stone has been removed and the marked point is empty again.
White fills the last liberty. The black stone comes off.

Size makes no difference. A wall of eight stones with one shared liberty falls to a single move, exactly like a lone stone. Only the liberty count protects a group, never the number of stones in it.

Capturing races

When two groups surround each other and neither can make eyes, they are in a capturing race (the Japanese term, used in English too, is semeai). Whoever fills the other side’s liberties first wins, and the losing group comes off the board.

A black two-stone group and a white two-stone group locked together in the middle of the board, each enclosed by the other side, with black's two liberties marked A and white's two marked B.AABB
Black's group has two liberties (A), white's has two (B). Neither side can escape, so this is a straight race.

Winning a race is arithmetic, not reading. Count your group’s liberties, count theirs, and compare. More than them and you win without doing anything clever. The same number, as above, and whoever moves first wins. Fewer, and you need a move that adds liberties to your group or takes one from theirs. If there is no such move, play elsewhere instead of feeding the loss.

One warning: points that are liberties of both groups at once, and eyes inside either group, change the count. Those cases are worth learning later. Count races where the two groups have separate liberties and you will be right nearly every time.

Ladders and nets

A stone with room to run cannot be caught by chasing it from behind. There are two standard ways to catch it anyway. A ladder keeps the running stone in atari move after move, driving it diagonally across the board until it hits the edge and dies. A net (geta) is a loose move played slightly ahead of the stone that takes away every escape route at once, without the chase.

Nets are the safer tool, because a ladder only works if nothing of the opponent’s colour is sitting in its path. Ladders and nets walks through both, including how to check whether a ladder works before you start one.

Snapback: losing one stone to take several

Sometimes a group looks safe because it can capture anything thrown into it. Snapback is the trick that punishes that. One stone is sacrificed so that the group capturing it ends up with a single liberty, and then the same point is played again.

White plays a single stone at the marked point 1 on the right edge, putting itself in atari beside two black stones that also have one liberty left.1
White plays 1 into its own atari. Black's two stones are now in atari too.

Black can capture that stone, and that is the mistake.

Black has captured the white stone, and the resulting three-stone black group has only the single marked liberty left.
Black takes the stone. Now three black stones share one liberty, the marked point.
White plays back at the same point and captures all three black stones, leaving white in full control of that corner.
White plays back at the marked point and takes all three. That is a snapback.

The lesson is short. Before you capture a stone that has been thrown into your shape, count what your own group’s liberties will be after the capture. If the answer is one, do not take it.

Why captured stones matter less than you think

Under the area scoring this site uses, captured stones are not worth points by themselves. Your score is your stones on the board plus the empty points you surround, so a prisoner sitting in a bowl adds nothing. What a capture gives you is the empty space it leaves behind and the strength of the wall you built while taking it.

That changes how captures should feel. Taking four stones in a corner you already controlled gains almost nothing, while a capture that turns a weak group of yours into a strong one can decide the game even if only one stone came off. How scoring works in Go shows the count in full, and strategy for beginners covers when a capture is worth chasing.

The other half of the picture is learning which groups can never be captured at all. A group with two separate eyes is safe forever, however few liberties it seems to have, and life and death in Go explains how to build one and how to take one away. To practise the counting, play a 9x9 game and count liberties before every contact move for a whole game. It slows you down at first, then stops being conscious.

Frequently asked questions

What is atari in Go?

Atari is the state of having exactly one liberty left, which means one more opponent stone captures the stones. It applies to a single stone or to a group of any size. It is a warning, not a result: a group in atari can often run, connect or capture something else first, and it can still end up winning the fight.

Can you capture more than one stone at a time?

Yes, and there is no limit. A connected group is captured as one unit, so filling the last liberty of a twenty-stone group removes all twenty at once. A single move can also capture two separate groups, if it happens to fill the last liberty of both. That is what makes the snapback above work.

Can I play again on a point where I just captured a stone?

The point is empty as soon as the stone is removed, so usually yes. The exception is a move that would repeat a board position that has already appeared, which the ko rule forbids. That rule exists to stop two single stones capturing each other back and forth forever.

Try it on the board →