This page presents the official Japanese Rules of Go, as used in Japan and most of Europe.
The material in the first two columns of this document appeared in chapter 13 of the first, 1992, edition of "The Go Player's Almanac 2001", by Richard Bozulich, published by Kiseido Publishing Company, ISBN 4-87187-040-5. The translation was by James Davies.
It appeared again in chapter 15 of the second, 2001, edition of the same work, by Richard Bozulich, published by Kiseido Publishing Company, ISBN 4-906574-40-8.
It was converted to html, adapted, and edited by Fred Hansen, with dagrams entered by Jonathan Cano. That html version can be seen at http://www.cs.cmu.edu/~wjh/go/rules/Japanese.html,
Nick Wedd then copied Fred Hansen's html, changed the formatting, and changed some text to bring it closer to Davies' original translation cited above. He added the "remarks and clarifications" column, and moved three remarks by Fred Hansen from the commentary to this column.
The Japanese Rules
[The following is the formulation of the Japanese rules of go in their entirety as revised on April 10, 1989 and effective from May 15, 1989.]
The Nihon Ki-in and Kansai Ki-in hereby revise the Nihon Ki-in's Rules of Go formulated in October 1949 and establish the Japanese Rules of Go. These rules must be applied in a spirit of good sense and mutual trust between the players.
Commentary on the Japanese Rules
Remarks and clarificationsThe text in this column is coloured to indicate who wrote it: Fred Hansen, Robert Jasiek and Nick Wedd.
For a fuller commentary, see Commentary on the Japanese 1989 Rules.
|Article 1 (a game of go)|
|Go is a game in which two players compete in skill on a board, from the beginning of the game until the game stops according to Article 9, to see which can take more territory. A game refers to the moves played until the end of the game.||Unless resumed, the game lasts until stopped by both players passing in succession. (See Articles 2, 9, and 10 for details.)|
|Article 2 (play)|
|The players can alternately play one move at a time, one player playing the black stones, his opponent the white stones.||
1. The players have the right to play alternately.
2. To declare that the game should stop, a player passes. If his opponent passes in succession, the game stops and neither player can play next. (See Article 9, clause 1.)
|A play is the act of placing a stone on the board (and removing any captured stones). A move is a play or a pass.|
|Article 3 (point of play)|
|The board is a grid of 19 horizontal and 19 vertical lines forming 361 intersections. A stone can be played on any unoccupied intersection (called an empty point) on which Article 4 permits it to exist. The point on which a stone is played is called its point of play.||
1. Being for professional players, these rules stipulate a 19 x 19 board.The players may of course agree to use other boards, such as a 9 x 9 beginners' board, a 13 x 13 board, or (in the future) a 21 x 21 board.
2. Intersection, empty point, and point of playThere are 361 intersections like that at 1 in Diagram 1. An intersection on which no stone has been placed is called an empty point. An intersection on which a stone like 1 has been placed is called its point of play.
Diagram 1. Intersections on the board.
3. Empty points that cannot be played on because of Article 4A player cannot play a move that would deprive his own stones of liberties, so that they could not exist on the board. For example, Black cannot play at any point marked x in Diagram 2. Note that Black can play at A because the resulting black group would have a liberty.
Diagram 2. Black cannot play at x, but can play at A.
|Article 4 Stones that may exist on the board|
|After a move is completed, a group of one or more stones belonging to one player exists on its points of play on the board as long as it has a horizontally or vertically adjacent empty point, called a liberty. No group of stones without a liberty can exist on the board.||
Stones that cannot exist: the white stones in Diagram 3 have no vertically
or horizontally adjacent liberties, so they cannot exist on the board.
Diagram 3. Stones that cannot exist on the board
|Article 5 (capture)|
|If, due to a player's move, one or more of his opponent's stones cannot exist on the board according to the preceding article, the player must remove all these opposing stones, which are called prisoners. In this case, the move is completed when the stones have been removed.|
|Article 6 (ko)|
|A shape in which the players can alternately capture and recapture one opposing stone is called a ko. A player whose stone has been captured in a ko cannot recapture in that ko on the next move.||
1. Shapes in which the players can alternately recapture one opposing stoneIn Diagram 5a, Black can capture the triangled white stones with move 1, and White can recapture Black 1.
Diagram 5 Kos.
2. Prohibition of recapture on the next moveAfter Black 1 in Diagram 5a, White cannot play at 4 in Diagrams 5b to recapture unless he first plays at least once elsewhere. A move played elsewhere for this purpose is called a "ko threat."
3. If a player recaptures on the next move without making a ko threat, he forfeits the game (Article 14).
|Article 7 (life and death)|
|Stones are said to be alive if they cannot be captured by the opponent, or if capturing them would enable a new stone to be played that the opponent could not capture. Stones which are not alive are said to be dead.||
1. When the game stops, ko recapturing also stops.Even if a player has unlimited ko threats (in a double-ko seki for example), he cannot use them to recapture a ko. Diagram 9 is an example of prohibition of recapture in a direct ko.
Black does not play A and claims that the game has ended. What happens? If the game ends in this way, the black group and the white stone are both dead. See Life-and-Death Example 9, below. It is clear the white stone is dead because Black can capture it by playing at A. The black stones are dead because when White captures by playing at B, Black must pass for that ko and then White captures the six remaining black stones by playing at A.
2. If a player whose stone has been captured in a ko has passed for that particular ko, the situation for that ko is the same as if the game had been resumed: the player may now capture in that ko again.
Diagram 10 Approach-move ko: an example of capturing again after passing.
The question in Diagram 10 is whether the game can end without Black's playing at A. The answer: If White does not actually fight the ko and the game ends in this position, the eight black stones are alive and the white stone is dead. Black does not have to add a move at A. See Life-and-Death Example 10.
3. Approach-move ko with double-ko seki (example of capturing again after passing for that particular ko capture).Suppose positions in Diagram 11 are both present on the board. The question is whether the game can end without Black's playing at A. The answer: If the game ends in this way, the white stone is dead despite the double ko in the position at the right. Black does not have to add a stone at A.
The reason the white stone is dead is as follows.
White 1 takes ko (on left) and Black 2 passes because recapturing is prohibited except after passing. White 3 gives atari. Black 4 retakes ko, a legal play because Black has passed once for this ko (in lieu of Black 2). White 5 takes a ko on the right and Black 6 takes the other ko. White 7 passes for the left ko, because recapturing without first passing is prohibited.
Black 8 captures two white stones on the left. White 9 and Black 10 pass for kos on the right. White 11 takes ko; this is legal because White has passed at play 9. Black 12 takes ko; this is legal because Black has passed at play 10.
Note that if White 7 was a pass for the ko 6/11 on the right, Black could have played 8 at 12 and captured the white group on the right. White could still not capture on the left and that Black group would remain alive.
|In the confirmation of life and death after the game stops in Article 9, recapturing in the same ko is prohibited. A player whose stone has been captured in a ko may, however, capture in that ko again after passing once for that particular ko capture.||
1. Examples of stones that are alive because they cannot be captured by the opponent.All the stones in Diagram 6 are alive.
Diagram 6. Live stones. (The lower right stones are alive in seki, Article 8.)
2. Examples of stones that are alive because capturing them would enable a new stone to be played that the opponent could not capture.In Diagram 7 White can capture Black on the next move at any of the x points, but Black can then play a stone that White cannot capture. This is known as a snapback. The black stones are therefore alive.
Diagram 7. Examples of snapback
(Note that the definition of "stones that cannot be captured" is recursive. The two black stones on the right are alive because when White captures them it enables Black to play as shown on the left. The black stone on the left is alive because when White captures it Black can recapture.)
3. Examples of dead stonesThe black stones in Diagram 8 are all dead.
Diagram 8. Dead stones. The black stones are dead. Clause 2 of Article 7 states how to settle unclear questions of life or death involving ko after the game stops (see Article 9, clause 1).
|Article 8 (territory)|
|Empty points surrounded by the live stones of just one player are called eye points. Other empty points are called dame. Stones which are alive but possess dame are said to be in seki. Eye points surrounded by stones that are alive but not in seki are called territory, each eye point counting as one point of territory.||
The basic principle is that territory consists of points surrounded
by completely independent live groups. Stones with dame that are alive
in seki are not independently alive, so the points they surround are
1. Eyes and territoryPoints a to d in Diagram 12 are eye points. The Black group surrounding them is completely alive, so they are territory.
Diagram 12. Eye Points.
2. Seki and damePoint a, in Diagram 13, is a dame. The ten black stones and four white stones are live stones with dame, so they are alive in seki. The points marked x are eye points but are not territory because the surrounding group is alive in seki.
Diagram 13. Seki and Dame.
3. Double ko sekiIn Diagram 14, points a and b are dame because they are not surrounded by live stones of one player. The six black and twelve white stones are live stones possessing dame, so they are alive in seki. (See Life-and-Death Example 25 for details.) The points marked x are not territory because they are surrounded by stones that are alive in seki.
Diagram 14. Double-ko seki.
4. Filling in the dame to confirm territory
In the position in Diagram 15, the black and white groups are both alive, but in seki because of the dame at A, so neither side has any territory. A move at A is needed to make Black's and White's eyes into territory.
A set of points that is connected via grid lines is said to be surrounded
by stones with a particular feature if the set is adjacent to stones with that
feature but not adjacent to empty points nor to stones without that feature.
"Stones which are alive but possess dame are said to be in seki".
It is not obvious what is meant here by "stones". There are three possibilities:
In the Hansen/Cano online version of this document, the stone at a15 in diagram 14 is shown as black. It should be white, and is shown as white in both editions of the "Go-Player's Almanac". This error was pointed out by William Brooks.
|Article 9 (end of the game)|
|When a player passes his move and his opponent passes in succession, the game stops.||A pass is a declaration that the game may stop. The game stops when both players pass in succession. That is, the game stops when both players indicate that they wish to pass.|
|After stopping, the game ends through confirmation and agreement by the two players about the life and death of stones and territory. This is called the end of the game.||
1. Confirmation of the life and death of stones and territory requires
that the players fill the dame and add any necessary stones inside
their territory, in accordance with Article 8.
2. If the players agree, they may fill the dame and add other necessary stones after stopping the game, in which case these are not moves as defined by the rules, and need not be played according to the rules.
|Note the words "confirmation .. by the two players".|
|If a player requests resumption of a stopped game, his opponent must oblige and has the right to play first.||
1. "If a player requests resumption..."The game is released from its stopped state and competition resumes.
2. "...his opponent...has the right to play first."a. If a game is resumed, any moves played not in accordance with the rules during the period when the game was stopped are invalid.
b. Arguments over who plays first are resolved by stating that the opponent of the player who requests resumption may play first.
3. "...his opponent must oblige..."If the opponent does not see any need to play, he may pass.
Resumption is superfluous, it adds nothing to the game other than
allowing the players' stupidity of forgetting to make some board-plays
already until the first game stop, and has hardly ever been used.
Resumption is hardly ever used explicitly, as few players are aware of its presence in the rules. It is frequently used implicitly, as when after the game stop a player indicates a teire and says "I will have to play here."
"If a game is resumed, any moves played not in accordance with the rules during the period when the game was stopped are invalid" .. and are presumably removed from the board.
|Article 10 (determining the result)|
|After agreement that the game has ended, each player removes any opposing dead stones from his territory as is, and adds them to his prisoners.||
A player does not have to remove opposing dead stones from his territory
by occupying all their liberties as in Article 5. He can
remove them as is, without making further moves.
1. Example of a stone that can be removed as is after the end of the game.After the end of the game, the white stone in Black's territory in Diagram 16 is dead, so Black can remove it without further play.
2. Example of stones that cannot be removed as is after the end of the gameThe black stones marked with triangles in Diagram 17 are dead, but White is alive in seki, so the points are not his territory. White therefore cannot remove these two black stones as is.
Note: Before the end of the game, White can play A to capture the two black stones, then capture another stone which Black has to throw in.
|This clause states that dead stones within territory are removed (and specifies who should remove them). No mention is made in the rules of dead stones not in territory. The implication, confirmed by the commentary, Example 9, is that they remain on the board.|
|Prisoners are then filled into the opponent's territory, and the points of territory are counted and compared. The player with more territory wins. If both players have the same amount the game is a draw, which is called a jigo.||If there are more prisoners than opponent's territory, the player adds the excess prisoners to his own territory when counting territory.|
|If one player lodges an objection to the result, both players must reconfirm the result by, for example, replaying the game.||The players have a duty to reconfirm the result, by replaying the game from the beginning for example. They cannot refuse to reconfirm the result.|
|After both players have confirmed the result, the result cannot be changed under any circumstances.||
Once the result is confirmed, it cannot be changed even if more prisoners
are found, or if examination of the game record shows that a player
has played twice in a row, recaptured in a ko without making a ko threat,
or made another illegal move (which according to Article 14
would result in immediate loss by forfeit before confirmation of the result).
I find this diagram useful:|
I disagree with [the above] flowchart...
Japanese professional (and amateur) playing practice tells us that in
between the game stop and the actions of [Article] 10 something happens that is
neither an explicit "confirmation and agreement by the two players
about the life and death of strings and territory" nor an explicit
reaching of the game end but an either formal, alternating or
non-formal, possibly not alternating filling of still unfilled so
called two-sided dame and so called teire.
Japanese professional (and amateur) playing practice tells us that in between the game stop and the actions of [Article] 10 something happens that is neither an explicit "confirmation and agreement by the two players about the life and death of strings and territory" nor an explicit reaching of the game end but an either formal, alternating or non-formal, possibly not alternating filling of still unfilled so called two-sided dame and so called teire.
|Article 11 (resignation)|
|During a game, a player may end the game by admitting defeat. This is called resigning. The opponent is said to win by resignation.|
|Article 12 (no result)|
|When the same whole-board position is repeated during a game, if the players agree, the game ends without result.||
1. Examples of repetition of the same whole-board position
This may occur in a triple or higher-order ko, round-robin ko, long life, etc. ee Diagrams 18.
Diagram 18. Triple ko, round-robin ko, and long life
2. "...if the players agree, the game ends without result."
In consideration of the difficulty of checking the repetition cycle, the game ends without result if both players agree.
It is not specified what happens if a position is repeated and the players
don't agree to end without result.
I understand the intention of this article as being that the players may repeat a position two or three times without effect, and then play some other line to break the cycle. But if it becomes clear to both that neither is going to break away from the cycle, then the game ends without result.
In Japan, "without result" means that the game was a non-event, and must be
replayed, possibly with faster time limits. This is not appropriate for the
usual conditions of British Go events. In Britain, games that end in this
way are treated as jigo (the precedent is the game Ellul-Herman in the Welsh
What would happen in the the British Championship best-of-five playoff match if
one player had two wins, the other had one win, and two games ended with triple-ko?
What would happen in the the British Championship best-of-five playoff match if one player had two wins, the other had one win, and two games ended with triple-ko?
|Article 13 (both players lose)|
|After the game stops according to Article 9, if the players find an effective move, which would affect the result of the game, and therefore cannot agree to end the game, both players lose.||
If an effective move is discovered after both players have passed,
such as a move that neither player can afford to let his opponent make,
and neither player requests that the game resume but the players do
not agree to end the game, then both players lose.
In the positions in Diagrams 19, after the game has stopped both players discover effective moves at A. Suppose both players would lose if their opponent played A, so neither requests resumption of the game. Then if the players do not agree that the game has ended, both players lose.
This can be discarded as a "Rule Nobody Wants to Apply".
This clause does not make sense. "The players find an effective
move .. and therefore cannot agree to end the game". The "therefore"
clause does not follow. The players do not disagree about anything.
They have passed, the game is coming to an end, it remains to confirm
the statuses of the groups and score the game. The fact that the players
are now aware that they had effective moves when they passed does nothing
to delay this process.
This clause is unnecessary. Preceding articles specify how
positions such as those in diagram 19 are to be scored.
This clause seeks to punish players who have done nothing wrong.
Its application will make the players unhappy. Their only crime is to
have played imperfectly. Players should not be punished for making bad
moves, beyond the in-game consequences of those moves.
I recommend ignoring clause 13.1. I shall do so myself.
This clause is unnecessary. Preceding articles specify how
positions such as those in diagram 19 are to be scored.
This clause seeks to punish players who have done nothing wrong. Its application will make the players unhappy. Their only crime is to have played imperfectly. Players should not be punished for making bad moves, beyond the in-game consequences of those moves.
I recommend ignoring clause 13.1. I shall do so myself.
|If a stone on the board has been moved during the game and the game has proceeded, the game continues with the stone returned to its original point of play. If the players cannot agree, both players lose.||
If the players cannot agree about returning the stone to its original
point of play, if another stone has already been played on this point,
if the stone could no longer exist on the board at this point, or if
for some other reason the stone cannot be returned to its original
point in accordance with the rules, then both players are held responsible
and both lose.
1. Note that if the game were to continue as is, it would not be possible to make a game record.
2. Note that the reason for having both players lose is that if the game were declared to end without result, a player who found himself behind might move stones intentionally.
Since in EGF tournaments tournament rules in rulesets of play are
overridden by the EGF's tournament rulesets, we should disregard the
tournament rules contained in J1989.
"If the game were to continue as is, it would not be possible to make a game record": nonsense, it doesn't seem any harder than recording a ko fight.
|Article 14 (forfeit)|
Violation of the above rules causes immediate loss of the game, provided
the result has not yet been confirmed by both players.
1. If an illegal move has been playedand the result of the game has not yet been confirmed, the game is forfeited at the point of the illegal move. Note: If the violation is discovered after the result has been confirmed, according to Article 10 clause 4, the result does not change.
2. Examples of illegal moves:playing twice in succession; capturing in a ko without making a ko threat.
|Examples of Confirmation of Life and Death|
|The results in the following examples would be reached through confirmation of life and death if the game stopped in the position shown in the diagram. They do not prevent these positions from being resolved through actual play before the end of the game.||
It is not clear who should do the confirmation. Two views are possible:
View 2 is favoured by some members of the European Go Association. It is supported by the existence of the many "Examples of Confirmation of Life and Death" below – material which is likely to be studied by referees but by few players.
Personally I favour view 2. A need for confirmation is most likely in games between weak players, and I, as referee, do not want to have to the task of explaining Article 7 Clause 2 (the "pass-for-ko" rule) to 25-kyu players.
|1. Positions Related to Article 7, Clause 1|
|Life-and-Death Example 1: Three Points Without Capturing|
If the game ends as shown in the diagram, the white stone and the four black stones are both alive. By Article 8, the position is a seki.
The black stones are alive in the confirmation phase as follows:
The four black stones are alive because capturing them enables the play of a stone (2) which is alive (in that it itself cannot be captured).
The white stone is alive in the confirmation phase as follows:
Caturing the one white stone enables the play of two white stones at 4 and 6 which cannot be captured, so the original white stone is alive.
Before the end of the game, either Black or White can play A to resolve the position by actual play.
If White plays A
first, capturing four black stones:
White captures 5 black stones; Black captures 3 white stones; White gains 2 points. (If Black plays and wins the ko, White gains 1 point.)
If Black plays A first (capturing a white stone)
White captures 5 stones and Black captures 2; White gains 3 points. (If white plays and wins the ko, White gains 7 points.)
|Life-and-Death Example 2|
This position is a seki. Black does not have to play A.
Reason why the two black stones are alive:
If White captures Black's two stones, Black can play two new stones (at 2 and 4) which White cannot capture. Since there is a dame, the position is a seki.
|Life-and-Death Example 3: Hane-Seki|
Black and White are both alive. By Article 8, the position is a seki. Neither player will play at A.
If White captures by playing at A,
Black will capture the entire corner.
Or if Black captures by playing at A
Black cannot avoid losing the entire corner. (Making responses to 2 and 4 is no better.)
Since neither player plays at A, the position remains as in the original diagram. It is a seki because there are dame.
|Life-and-Death Example 4|
Black and White are both alive. By Article 8, the position is a seki. Black can gain 9 points by capturing one of the white groups before the end of the game instead of leaving the position as a seki.
Black gets 8 prisoners and 9 points of territory, while White gets 6 prisoners and 2 points of territory.
|Life-and-Death Example 5|
The enclosed black and white stones are all alive. By Article 8, the position is a seki.
If Black tries to capture White before the end of the game he loses one point: Black gets 5 prisoners and 3 points of territory while White gets 7 prisoners and 2 points of territory (ignoring the possibility of a ko). If White begins he can gain 1 point, getting 7 prisoners and 3 points of territory while Black gets 6 prisoners and 3 points of territory.
|Life-and-Death Example 6: position before long life|
The diagram shows a position one move prior to the start of a long life. Black A would create long life (cho sei), causing the game to end without result. Suppose that White would lose by half a point if he played A. The question is what happens if the game ends with neither player playing A.
Black's ten stones are dead because they die if White plays A. White's four stones are alive because even if Black plays A, they survive in the ensuing long life. Black's ten stones are therefore dead stones in territory surrounded by live white stones. If the game ends as shown, White can remove the ten black stones as is, without having to play A.
|2. Positions Related to Article 7, Clauses 1 and 2|
|These examples illustrate the special ko rule in force during the confirmation phase after both players have passed in successive turns. This ko rule allows a recapture of a ko only after a pass by the player about to make the recapture. Moreover, there must be one pass designated for each ko that is to be recaptured. For instance, if Black has captured two kos and White has not yet passed for either, then White will have to pass once for one of the kos and then again for the other. The recapture in the first ko can be before or after the pass for the second ko, it can even be after the recapture in the second ko. Example 7-2 will illustrate why each pass must be designated as to which ko it satisfies.|
|Life-and-Death Example 7-1: Bent Four in the Corner|
The three black stones are alive and the seven white stones are dead.
Here is how Black can demonstrate capture of the white stones during the confirmation phase:
|Life-and-Death Example 7-2: Bent Four in the Corner and Thousand-Year Ko|
The bent-four-in-the-corner of Life-and-Death Example 7-1 is dead even if a thousand-year ko, as shown here on the right, is also present on the board. Here is how Black can demonstrate capture of the seven white stones on the right, during the confirmation phase:
|Life-and-Death Example 8: triple ko with an eye on one side|
Black's nine stones are dead and White's ten are alive.
In the confirmation phase, the black stones can be captured as follows.
|I would not call this a "real" triple ko, because the three kos are not all between the same two groups.|
|Life-and-Death Example 9: Resolving a Direct Ko|
If the game ends like this, Black and White are both dead but none of the stones can be removed. According to Article 8 there is no territory. Compared with playing A, Black loses 3 points.
White's stone is clearly dead because Black can capture it at A. The
reason why Black's seven stones are dead is as follows.
|Life-and-Death Example 10: approach-move ko|
The question is whether Black has to play A before the end of the game. The answer: If White does not actually play out the ko and the game ends as shown, White's stone is dead, the eight black stones are alive, and Black does not have to play A.
Black's eight stones are alive for the following reason:
|Life-and-Death Example 11: False Eye with Double Ko|
If both these positions are present on the board, the seven white stones on the left are dead while the enclosed black and white groups on the right are both alive in double-ko seki.
Here is why the seven white stone are dead:
|Life-and-Death Example 12: thousand-year ko|
If the game ends with this position on the board, Black and White are both alive in seki. By Article 8, the position is a seki.
Why Black cannot kill the white stones:
The result through White 6 shows that White is alive if Black plays
first. If White plays first to try to kill the Black group, it lives
in the following sequence through Black 4.
|Life-and-Death Example 13|
Black and White are both alive. By Article 8, the position is a seki.
Here is why Black cannot kill White:
|Life-and-Death Example 14|
The eight black stones are alive and the seven white stones are dead. To gain a seki, white has to play at A.
|Life-and-Death Example 15|
The four black stones are alive and the eleven white stones are dead.
|Life-and-Death Example 16|
The ten white stones in the left corner are dead. The eleven white stones to the right also die through collapse of the seki.
|Life-and-Death Example 17|
The three black stones in the corner are alive. The ten white stones surrounding them are dead. The eleven surrounded white stones to the right also die through collapse of the seki.
|Life-and-Death Example 18|
The seven black stones in the corner are dead. The black group in the center dies through collapse of the seki.
|Life-and-Death Example 19|
White is alive and Black is dead.
|Life-and-Death Example 20|
White and Black are both alive. By Article 8, the position is a seki.
|Life-and-Death Example 21|
The nineteen black stones are alive and the fourteen white stones are dead.
|Life-and-Death Example 22|
The seven black stones are alive and the ten white stones are dead. Black does not have to add a move to capture the three white stones.
|Life-and-Death Example 23|
From Article 7 clauses 1 and 2 and the purpose of the game stated in Article 1, Black is alive and White is dead. If White plays A before the end of the game, the position becomes a seki, but Black can capture 9 white stones while White captures 1 black stone.
|Life-and-Death Example 24: Filling Dame to Obtain Territory|
a. In this position, the black and white groups are both alive, but in seki because of the dame at A, so neither side has any territory. A move at A is needed to make Black's eyes into territory.
b. If there is a double-ko seki on the board, White can fight the kos at B and C. From Article 7, the triangled white stone is dead and the squared white stone is alive, so B is a dame and C is an eye.
c. Even if the dame at A is filled, White is alive in seki because of the dame at B, so White's two eyes and the point C are not territory. To get two points of territory, White must play at B and C.
|Life-and-Death Example 25: Double-Ko Seki|
a. Black's five-stone group and White's eleven-stone group are alive but have dame at A and B. By Article 8, they are alive in seki.
b. The reason A and B are dame is as follows.