Current Article  

Go rules

Detailed rules

image:go_final.png

See also: Go, Go strategytactics, Go concepts

Game equipment

A Go board (gobanJapanese; badukpanKorean) isgrid19 horizontal19 vertical lines, forming 361 intersections. For beginning players or short games, smaller boards13x13 or 9x9 intersectionssometimes used, without otherwise changingrules.

Playing pieces consisttwo setsstones (go-ishi), one black setone white set. The numberstonesindefinite (the rules assume an endless supply) but 181 black stones180 white stonessufficientcover361 intersections ofboard, so these amountsusually found infull set.

Sincenumberstoneslarge, theystoredbowls (go-ke), oneeach player; this usually haslid which, upturned before play,usedhold captured stones.

Game play

Go isgametwo players. One player usesblack stones,other white. The board starts empty. Black moves first (this givesslight advantage, soweaker player traditionally plays Black;handicap can be usedgive Black several starting moves, see below). (In ancient China,was White who moved first.)

The players alternate making moves. Makingmove consistsputtingsingle stone on one ofintersections (the intersections atedgescorners ofgridpart ofboardplays therealso valid). Once played,stone does not move,remains atsame point unless itcaptured. A playerallowedpass insteadmakingmove. A player may also resign on his move, conceding victory toopponent.

Stones ofsame color thatdirectly adjacent (alonglines ofboard)saidbe connected intostring. Stones onboard havecertain numberadjacent empty intersections, called liberties. Whenstone, or stringstones, has no remaining liberties, itcaptured. The entire stringtaken offboard,added toopponent's prisoner pile.

Ko

image:goko.gif

To prevent endlessly repeating positions,ruleko (a Japanese word"eternity") prevents any play that would repeatprevious board position.

This occurs most often whenstone has just been captured, andstone which madecaptureleftonly one remaining liberty. If recapturing that stone would recreatesame board position fromprevious move,positioncalled ko, andrecapturing moveillegal. The ruleko states thatplayer may not recapture on their next movemust play elsewhere. Afternew move,board position will be different, andstone may then be recaptured.

Suicide

Ifstoneplayed such thathas no remaining liberties (orpart ofstringno remaining liberties)does not gain liberties by immediately capturing an opponent's string, thistermed suicide sincestone,any stoneswas connected to, would be thus reducedzero libertiescaptured. Though itusuallymere tactical blunderdo so, many rule sets prohibitsuicide play, makingan invalid move.

Note that suicide ofsingle stone (playing on an empty point completely surrounded byopponent) would causeboard positionrepeat,would thus be invalid underKo rule even when using rules that permit suicide.

Game end

When both players have passed,game has ended. Dead stones (those that remain onboard but cannot avoid capture)now removed as ifwere captured. Most rule sets allow disputes overstatusstringsloosely-connected groupsstringsbe resolved simply by continuing play until both playersagreed. The Japanese rules, instead, havelong listexceptionsprecedents thatreferredin tournament play. Most players remain unawarethese complications inJapanese rules forvast majoritytheir games.

After dead stone removal, counting beginsdetermine which player iswinner withgreater share ofboard. Theretwo methodsscoring. InJapanese, or territory scoring method, each player scoresnumberempty intersections he has enclosed,subtractsnumbercaptures taken from him (thisdone easily by placingcaptures taken fromplayer into their empty intersectionsreducescore). InChinese, or area scoring method, capturesnot scored, butplayer scoresevery intersection that he controls -- that is, all points where he has placedstone or thatcompletely surrounded by his stones.

Whichever scoring methodused,playermost points wins. In normal circumstances,ChineseJapanese scoring methods givesame winner.

HandicapsKomi

To allow playersdifferent skillscompete fairly, handicapskomiused. Theseconsideredpart ofgame,unlikemany gamesdo not distortnature ofgame. Players at all levelsstrength employ handicapsmakegame more balanced.

image:go_handicap_points.png

Handicap stones

Handicapsgiven by allowingweaker playertake Black,declaring White's first few moves as mandatory "pass" moves. In practice, this means that Black's first move isplaceset numberstones (usuallynumberequal todifference inplayers' ranks) onboard before allowing Whiteplay. Traditionally,"star points" -- strategically-important intersections markedsmall dots --usedplace these handicap stones. On19x19 board, therenine star points: atfour 4-4 points incorners, atfour 4-10 points alongsides,one at10-10 point (the centre ofboard, or tengenJapanese). Other board sizes do not necessarily have marked star points.

When Blackonly one rank weaker (also known as one stone weaker, due toclose relationship between ranks andhandicap system) hegivenadvantageplaying Black, but without any mandatory White passes. For rank differences from two through nine stones,appropriate numberhandicap stonesused. Beyond nine stones,differencestrength betweenplayersusually considered great enough thatgamemorelesson,White teaching Black, so nine stones isnominal upper limit on handicap stones regardless ofdifferencerank (though higher numbersstones, like thirteen or seventeen, can be given ifteacher wants more ofchallenge).

Komi

In an "even", or non-handicap game, Black's initial advantagemoving first can be offset by komi (compensation points):fixed numberpoints, agreed beforegame, addedWhite's score atend ofgame. The correct valuekomi (to properly compensateBlack's advantage)controversial, but common values5.5, 6.5 or 7.5 --fractional value avoidstied game. Inhandicap game, komiusually set0.5 (i.e. White wins ifgametied). A handicap game withhandicap1 starts like an even game, but White receives only 0.5 komi (i.e.White player whostronger by one rankhandicapped only by Black's first-move advantage).

StrategyTactics

See Go strategytactics.

Sample game

Seesample game, on9x9 board, by two professional players.

Rule Sets

Theremany official rule setsplaying Go. These varysignificant ways, such asmethod usedcountfinal score,in very small ways, such as whethertwo kinds"bent four incorner" positions resultremoval ofdead stones automatically atend ofgame or whetherposition must be played out,whetherplayers must startgame withfixed numberstones oran unbounded number.

Rule sets include AGA (American Go Association), Chinese, Japanese, Korean, French, New Zealand,various modifications such as thosesimple games, IGS (Internet Game Server), Ing Chang-Ki's rules, etc.

Further detailed information may be found atfollowing external links. Note that no one link hascomplete listall commonly used rule sets,mostthese links do not have complete information any one rule set. However, full information can be found by traversing links located at these Web sites.

External Rule Set Links


Copyright 2004. All rights reserved.