Changes

Two players, ''Black'' and ''White'', take turns placing a ''stone'' (game piece) of their own color on a vacant ''point'' (intersection) of the grid on a Go board. Black moves first.  Normally, the grid measures 19&times;19 lines, though the rules can be freely applied to all grid sizes. Grid sizes 9&times;9 and 13&times;13 are often used to teach beginners and still offer a challenging game to experienced players. Once played, a stone may not be moved to a different point.<ref>[http://www.nihonkiin.or.jp/lesson/school-e/okikata-e.htm How to place Go stones] Retrieved March 4, 2007</ref><ref>[http://gobase.org/studying/rules/?id=1&ln=uk The Go Board] Retrieved March 4, 2007</ref>

Two players, ''Black'' and ''White'', take turns placing a ''stone'' (game piece) of their own color on a vacant ''point'' (intersection) of the grid on a Go board. Black moves first.  Normally, the grid measures 19&times;19 lines, though the rules can be freely applied to all grid sizes. Grid sizes 9&times;9 and 13&times;13 are often used to teach beginners and still offer a challenging game to experienced players. Once played, a stone may not be moved to a different point.<ref>[http://www.nihonkiin.or.jp/lesson/school-e/okikata-e.htm How to place Go stones] Retrieved March 4, 2007</ref><ref>[http://gobase.org/studying/rules/?id=1&ln=uk The Go Board] Retrieved March 4, 2007</ref>

Orthogonally adjacent stones of the same color form a ''chain'' (also called a ''group'') that shares its [[Go terms#Liberty|liberties]] (see below) in common, cannot subsequently be subdivided, and in effect becomes a single larger stone<ref>{{cite web | url = http://senseis.xmp.net/?Chain | title = Chain | author = Sensei's Library | accessdate = 2007-11-27 }}</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 playing additional stones on adjacent intersections or connected together by playing a stone on an intersection that is adjacent to two or more chains of the same color.

Orthogonally adjacent stones of the same color form a ''chain'' (also called a ''group'') that shares its [[Go terms#Liberty|liberties]] (see below) in common, cannot subsequently be subdivided, and in effect becomes a single larger ston. 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 playing additional stones on adjacent intersections or connected together by playing a stone on an intersection that is adjacent to two or more chains of the same color.

[[Image:Go capturing.png|thumb|left|If white plays at A, the black chain loses its last liberty. It is captured and removed from the board.]]

[[Image:Go capturing.png|thumb|left|If white plays at A, the black chain loses its last liberty. It is captured and removed from the board.]]

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

[[Image:File: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''.<ref>{{cite web | url = http://senseis.xmp.net/?path=KoFighting&page=BasicsOnKos | title = Basics On Ko's | author = Sensei's Library | accessdate = 2007-12-20 }}</ref>

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''.

Instead of placing a stone, a player may ''pass'', indicating that he sees no way to increase his territory or reduce his opponent's territory. When both players pass consecutively, the game ends and is then [[Rules of Go#End|scored]].

Instead of placing a stone, a player may ''pass'', indicating that he sees no way to increase his territory or reduce his opponent's territory. When both players pass consecutively, the game ends and is then [[Rules of Go#End|scored]].