Changes

Generally, it is not allowed to play a stone in such a way that one of your own chains is left without liberties. Such a move is dubbed ''suicide''. An exception to this rule occurs if doing so captures one or more of the opponent's stones. In this case, the opponent's stones are captured first, leaving the newly played stone at least one liberty.  

Generally, it is not allowed to play a stone in such a way that one of your own chains is left without liberties. Such a move is dubbed ''suicide''. An exception to this rule occurs if doing so captures one or more of the opponent's stones. In this case, the opponent's stones are captured first, leaving the newly played stone at least one liberty.  

[[Image:File:Go ko.png.jpg|thumb|right|An example of a situation in which the ko rule applies.]]

[[Image:Go ko.png.jpg|thumb|right|An example of a situation in which the ko rule applies.]]

Players are not allowed to make a move that returns the game to the position before the opponent's last previous move. This rule, called the ''[[Rules of Go#Ko (no repetition of the same shape)|ko rule]]'', prevents unending repetition.<ref>{{cite web | url = http://senseis.xmp.net/?Ko | title = Ko | author = Sensei's Library | accessdate = 2007-12-20 }}</ref> See the example to the right: Black has just played the stone marked '''1''', capturing a white stone at the intersection marked with a circle. If White were now allowed to play on the marked intersection, that move would capture the black stone marked '''1''' and recreate the situation before Black made the move marked '''1'''. Allowing this would result in an unending cycle of captures by both players. The ko rule therefore prohibits White from playing at the marked intersection. Instead White must play elsewhere; Black can then end the ko by filling at the marked intersection, creating a five-stone Black chain. If White wants to continue the ko, she will try to find a play that Black must answer; if Black answers, then White can retake the ko. A repetition of such exchanges is called a ''ko fight''.

Players are not allowed to make a move that returns the game to the position before the opponent's last previous move. This rule, called the ''[[Rules of Go#Ko (no repetition of the same shape)|ko rule]]'', prevents unending repetition.<ref>{{cite web | url = http://senseis.xmp.net/?Ko | title = Ko | author = Sensei's Library | accessdate = 2007-12-20 }}</ref> See the example to the right: Black has just played the stone marked '''1''', capturing a white stone at the intersection marked with a circle. If White were now allowed to play on the marked intersection, that move would capture the black stone marked '''1''' and recreate the situation before Black made the move marked '''1'''. Allowing this would result in an unending cycle of captures by both players. The ko rule therefore prohibits White from playing at the marked intersection. Instead White must play elsewhere; Black can then end the ko by filling at the marked intersection, creating a five-stone Black chain. If White wants to continue the ko, she will try to find a play that Black must answer; if Black answers, then White can retake the ko. A repetition of such exchanges is called a ''ko fight''.