Column Go

Before the move  

The white stone is almost surrounded. It is adjacent to only one unoccupied point, marked . Thus, the stone has only one liberty.

Remember: only adjacent points can be liberties. So the points marked are not liberties.

Black captures  

Black's move occupies the last liberty of the white stone, surrounding it completely. It is thus captured and will be placed under . .

After the move  

The captured stone is under .

Example 2: capture of three stones in a corner

Before the move  

The three white stones are adjacent to one another and share liberties. As a string, the stones stand or fall together.

Black captures three stones  

Black's move occupies their last liberty and captures them, placing the adjacent to under it and that adjacent to the others under either of them.

After the move  

from a is under , from b is under .

Example 3: capture of two strings

A move can also surround different stones at the same time even if not all of them are connected as a string.

Before the move  

Here, a is the only liberty of two separate strings: the four white stones at the top and the single white stone in the middle.

Black captures 5 stones  

Black's move captures the surrounded five white stones. For this Black occupies their last liberty. They now have no liberties, so they are captured and thus placed under Black’s stones. Three of them thus go under .

After the move  

from a, b and c are under , from d is under .

Example 4: capture by a stone with no liberties

This example illustrates the rule that a capturing stone doesn’t need to have a liberty until the captured stones are removed.

White captures  

The White move occupies the last liberty of the two black stones, capturing them. Note that is a legal move although it has no liberties when it is played.

After the move  

Now has a liberty again with from a underneath, leaving a legal position. from b is under the other on the same row of the board. If Black plays at a, there will not be a ko.