Editing Life and death (section)

==Explanation==
The concept of life and death is a consequence of two basic Go rules.

* A group of stones with no [[List of Go terms#Liberty|liberties]] is captured.
* A stone may not be played on a position where it will be captured directly, unless it directly captures another group.

Because of these rules, some groups can never be captured (and thus are ''alive''), while others cannot avoid capture (and thus are ''dead'' even if they have not yet been removed from the board).

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{{Goban 9x9
|ulA|  b|  u|  u|  u|  u|  w|  b|urB
|  b|  b|   |   |   |   |  w|  b|  b
|  l|   |   |   |   |   |   |  w|  w
|  l|   |   |   |   |   |   |   |  r
|  l|   |   |   |   |   |   |   |  r
|  l|   |   |   |   |   |   |   |  r

|  w|  w|  w|  w|   |   |   |   |  r

|  b|  b|  b|  b|  w|   |   |   |  r
|dlC|  b| dD|  b|  w|  d|  d|  d| dr|20}}

The group at '''a''' is not alive, but may become alive, so is ''unsettled''. The group at '''b''' is ''dead''. The group at '''c''' and '''d''' is ''alive''.
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=== Examples ===

See the diagram on the right, and suppose white tries to capture the black groups:
:*'''a''': White is not allowed to play '''a''', because a white stone at '''a''' would be captured immediately, and so would be a suicide.

:*'''b''': White may play '''b''', because the black group will be completely surrounded ''first'', and thus it is captured, and the black stones will be immediately removed from the board.

:*'''c''' & '''d''': White cannot play '''c''' or '''d''' because the black group still has another liberty after one stone is placed. So, playing at '''c''' or '''d''' would be suicide.

The black group surrounding '''c''' & '''d''' can never be captured, so it is called ''alive''. The group has two separate liberties, where white cannot play. A group such as '''b''' that cannot become alive is called ''dead''. Groups that are neither ''alive'' nor ''dead'' are called ''unsettled'', and their fate will be resolved later.

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{{Goban 9x9
|ulE| uE|  b|  F|  F|  b|  u|  u| ur
|  b|  b|  b|  b|  b|  b|   |   |  r
|  l|   |   |   |   |   |   |   |  r
|  l|   |   |   |   |   |   |   |  r
|  l|   |   |   |   |   |   |   |  r
|  l|   |   |   |   |   |   |   |  r
|  w|  w|  w|  w|   |   |   |   |  r
|  b|  b|  b|  w|   |   |   |   |  r
| dl|  b|  G|  b|  w|  d|  d|  d| dr|20}}
'''e''' and '''f''' are eyes, '''g''' is a false eye.
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=== Eyes and false eyes ===
Liberties inside a group are called ''eyes''. In the previous example, '''a''', '''b''', '''c''' and '''d''' are eyes. An eye may be a single empty intersection, or more of them. In the diagram on the left, the intersections marked '''e''' form a single eye, and '''f''' forms another eye. The group has two—separated—eye spaces. Even though white can make a move in these eyes, black could eventually capture the white stones, and each eye would thereby be reduced to a single intersection.

An inner liberty where the opponent can still capture part of the group that encloses this liberty is called a 'false eye' or 'deficient eye'. A group with only one eye is not alive. In the example on the left, white can play at '''g''', and capture a black stone. That eye is then destroyed, and black has only one eye left, so that group is now ''dead''.  The black group at '''g''' is dead, because it can not form two true eyes.