Editing Go (game) (section)

=== Suicide ===
[[File:Gochsurule.png|thumb|Under normal rules, White cannot play at A because that point has no liberties. Under the Ing<ref name="ing_rules">Ing rules of Go, translation archived by [[American Go Association]] website [https://www.usgo-archive.org/files/pdf/IngRules2006.pdf], {{webarchive|url=https://web.archive.org/web/20130112214116/http://www.usgo.org/files/pdf/IngRules2006.pdf|date=12 January 2013}}, retrieved 5 August 2012</ref> and New Zealand rules,<ref name="AGA_rules">{{Cite web|title=The Rules of Go |website=American Go Association|url=https://www.usgo-archive.org/rules-of-go|access-date=5 August 2012|archive-url=https://web.archive.org/web/20120711140721/http://www.usgo.org/rules-go|archive-date=11 July 2012}}</ref> White may play A, a suicide stone that kills itself and the two neighboring white stones, leaving an empty three-space eye. Black naturally answers by playing at A, creating two eyes to live.]]

A player may not place a stone such that it or its group immediately has no liberties unless doing so immediately deprives an enemy group of its final liberty. In the second case, the enemy group is captured, leaving the new stone with at least one liberty, so the new stone can be placed.{{sfn|Kim|Jeong|1997|p=30}} This rule is responsible for the all-important difference between one and two eyes: if a group with only one eye is fully surrounded on the outside, it can be killed with a stone placed in its single eye. (An [[List of Go terms|eye]] is an empty point or group of points surrounded by a group of stones).

The [[Rules of go#Ing rules|Ing]] and New Zealand rules do not have this rule,<ref name="Suicide in different rules.">{{cite web|title=Comparison of Some Go Rules|url=https://www.britgo.org/rules/compare.html|publisher=British Go Association|access-date=15 May 2014}}</ref> and there a player might destroy one of its own groups (commit suicide). This play would only be useful in limited sets of situations involving a small interior space or planning.{{sfn|Kim|Jeong|1997|p=28}} In the example at right, it may be useful as a [[#Ko fighting|ko threat]].