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BasicRulesOfGo
RulesOfGo
EyesWinSemeais
JapaneseRules
ChineseRules

 

Suicide
  Difficulty: Advanced   Keywords: Tactics, Rules

The term 'suicide' denotes a move which is played such that the stone that is played has no liberties. In Japanese rules, suicide moves are forbidden, but some other rulesets, such as the Ing rules do allow suicide, at least when it is suicide of more than one stone. A suicide of one stone does not change the board situation, and thus such a move is (depending on the ruleset) either equivalent to, or worse than passing. Suicide of more than one stone on the other hand, can make a difference.


[Diagram]
Diag.: Suicide as a ko threat

The simplest, and best known, situation where suicide can make a difference is as a ko threat. In this position, the black group is alive. However, if white is allowed to play the suicide move of white 1, taking 3 white stones off the board, black will have to come back at the same point to make two eyes. If white is not allowed to suicide, she has no ko threat here.



[Diagram]
Diag.: A semeai

But sometimes suicide also makes a difference for the outcome of a semeai. In this diagram, if white is not allowed to play suicide, she is dead. There is no way for white to avoid that black first fills up two liberties with 1 to 5, then captures at 7, resulting in the next diagram.


[Diagram]
Diag.: black wins

Playing at white to prevent black from getting two eyes will not help white. Black plays atari at 2, and white is dead. Note that these diagrams are just used to show that white is indeed dead - black need not hurry to take the stones off the board.


[Diagram]
Diag.: suicide

If suicide is allowed, white does have a recourse in this situation: She can play the suicide move of white 2. The result is shown in the next diagram.


[Diagram]
Diag.: White wins

After white 4, the position is a seki; neither player can make any useful move - so this time, white lives. If black plays 1 or 3 at 2 or 4 or A, the position is seki as well, each player having one eye and no external liberties.



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This is a copy of the living page "Suicide" at Sensei's Library.
(C) the Authors, published under the OpenContent License V1.0.