Editing Go (game) (section)

===Liberties and capture===
[[File:Go capturing.png|thumb|left|The Black stone group has only one liberty (at point A), so it is very vulnerable to capture. If Black plays at A, the chain would then have 3 liberties, and so is much safer. However, if White plays at A first, the Black chain loses its last liberty, and thus it is captured and immediately removed from the board, leaving White's stones as shown to the right.]]
Vertically and horizontally adjacent stones of the same color form a chain (also called a ''string'' or ''group''),{{sfn|Fairbairn|2004|p=7}} forming a discrete unit that cannot then be divided.<ref>{{citation | url = http://nrich.maths.org/public/viewer.php?obj_id=1433 | title = Behind the Rules of Go | last = Matthews | first = Charles | publisher = University of Cambridge | access-date = 2008-06-09}}</ref> Only stones connected to one another by the lines on the board create a chain; stones that are diagonally adjacent are not connected. Chains may be expanded by placing additional stones on adjacent intersections, and they can be connected together by placing a stone on an intersection that is adjacent to two or more chains of the same color.<ref name="Go Board Game pdf">{{cite web|title=Go The Board Game|url=http://kopoint.files.wordpress.com/2012/12/go-the-game.pdf|access-date=20 August 2014|archive-url=https://web.archive.org/web/20130725124759/http://kopoint.files.wordpress.com/2012/12/go-the-game.pdf|archive-date=25 July 2013|url-status=dead}}</ref>

A vacant point adjacent to a stone, along one of the grid lines of the board, is called a ''liberty'' for that stone.{{sfn|Kim|Jeong|1997|p=12}}{{sfn|Fairbairn|2004|p=6}} Stones in a chain share their liberties.{{sfn|Fairbairn|2004|p=7}} A chain of stones must have at least one liberty to remain on the board. When a chain is surrounded by opposing stones so that it has no liberties, it is captured and removed from the board.{{sfn|Dahl|2001|p=206}}

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