International Rules

In June 1998 the international mailing list "go-rules" at go-rules@usgo.org (which no longer exists) has sincerely discussed international rules and decided to contribute to creation of unified go (igo, weiqi, baduk) rules that shall be suitable for international usage. Thereby created rule texts and comments are presented on this page.

This page proposes variants to existing rules. It is based on http://home.snafu.de/jasiek/int.html

Table of contents Core Rules of Play Rule Text (General) (Move) (No Repetition) (Agreement) (Scoring) Alternative: No Suicide (Move) (No Suicide) Alternative: Basic Ko And Exceptional Game Ends (No Repetition) Alternative: Equivalence Scoring (Prisoners) (Scoring) Tournament Rules Resignation Tie Counting Komi Handicap Stones Thinking Times See also

Core Rules of Play

Rule Text

(General)

1. Two players play the game with stones on a board. The aim is to have more points at the end.
2. One player uses black stones, the other white.
3. The player with the black stones starts the game.
4. The board is a grid of 19 horizontal and 19 vertical lines forming 361 intersections.
5. Two intersections are adjacent if they have a line but no intersection between them.
6. Two intersections with either black, white, or no stones on them are connected if they are adjacent or if there is a chain of adjacent intersections of their type between them.
7. A region consists of an intersection and any intersections connected to it.

(Move)

1. The players move alternately.
2. A move is either a play of an own stone on an empty intersection, or a pass.
3. A play causing stones' regions to be without any adjacent empty intersections removes those stones. Removing opposing regions takes precedence over removing own regions.

(No Repetition)

A play may not recreate a previous board position from the game. This refers to the position just after the play and any consequent removals.

(Agreement)

1. Alternate moving stops with two successive passes.
2. Then the players may make an agreement about all regions that shall be removed.
3. If they agree, they remove those regions. Then the game ends with scoring.
4. If they disagree, alternate moving continues with the opponent of the last passing player.
5. If then both players just pass, the game ends with scoring.

(Scoring)

1. The points of each player are the numbers of intersections
   • a) with his stones, and
   • b) of the empty regions only adjacent to intersections with his stones.
2. The player with more points wins the game.

Alternative: No Suicide

(Move)

1. The players move alternately.
2. A move is either a play of an own stone on an empty intersection, or a pass.
3. A play causing opposing stones' regions to be without any adjacent empty intersections removes those stones.

(No Suicide)

A play causing a remaining own region to be without any adjacent empty intersections is prohibited.

Alternative: Basic Ko And Exceptional Game Ends

(No Repetition)

1. A play may not remove a single stone if this stone has removed a single stone in the last preceding play.
2. If a play recreates a previous board position and if between the two occurrences the difference of numbers of removed black and white stones is zero, then the game exceptionally ends without result.
3. If a play recreates a previous board position and if between the two occurrences the difference of numbers of removed black and white stones is not zero, then the game exceptionally ends with a win of the player with fewer removed stones.
4. Recreation refers to the position just after a play and any consequent removals.

Alternative: Equivalence Scoring

(Prisoners)

1. Any stone that is removed from the board before the end of the game is kept as a prisoner.
2. Each time a player passes he adds an own stone to the prisoners.
3. Just before scoring white makes an extra pass if he has not passed as the last player.

(Scoring)

1. The players may score either area or territory, which are equal.
2. The points of area of each player are the numbers of intersections
   • a) with his stones, and
   • b) of the empty regions only adjacent to intersections with his stones.
3. The points of territory of each player are the numbers of
   • a) intersections of the empty regions only adjacent to intersections with his stones, and
   • b) the prisoners that are opposing stones.
4. The player with more points wins the game.

Tournament Rules

Resignation

1. Before the end of a game a player may resign it.
2. Resignation immediately and exceptionally ends the game.
3. The opponent of the resigning player wins the game by resignation.

Tie

1. If the scores of both players, possibly considering compensation points, are equal, then the game is a tie.
2. The tournament organization is suggested to treat a tie as 0.5 won games for each player.

Counting

1. Counting methods mechanically determine the scores.
2. Before a tournament the tournament organization may specify a counting method to be applied.
3. The following counting methods for area scoring are possible:
   • a) point by point counting for area scoring,
   • b) point by point half counting for area scoring,
   • c) stone counting for area scoring,
   • d) Chinese half counting for area scoring.
4. The following counting methods for territory scoring are possible:
   • a) point by point counting for territory scoring,
   • b) Japanese counting for territory scoring.
5. Point by point counting for area scoring:
   • a) First the black score, then the white score, then the empty intersections that do not score are counted.
   • b) Each count is performed by scanning the intersections of the board using a finger. It denotes any intersections belonging to an according count. The intersections are added.
   • c) The sum of the counts for the black score, the white score, and the empty intersections that do not score has to equal the total number of intersections of the board (361 for a 19x19 board).
   • d) The winner is the player of the higher count for the black score respectively the white score. He is said to win by the positive difference of the two counts.
6. Point by point half counting for area scoring:
   • a) I is the total number of intersections of the board (I = 361 for a 19x19 board).
   • b) N is the number of empty intersections that do not score.
   • c) H is half the difference of I and N, i. e. H = (I - N) / 2, and the reference point for the half count.
   • d) The black score B is counted.
   • e) The count is performed by scanning the intersections of the board using a finger. It denotes any intersections belonging to the count. The intersections are added.
   • f) B is compared with H. Black wins if B is greater than H (B > H). White wins if B is smaller than H (B < H). The game is a tie if B and H are equal (B = H).
   • g) The winner is said to win by twice the positive difference of B and H.
7. Stone counting for area scoring:
   • a) All empty intersections that score for black respectively white are filled with black respectively white stones.
   • b) As long as possible, a pair of one black and one white stone is removed from the board.
   • c) The player of whom stones remain on the board is the winner. If no stones remain, then the game is a tie.
   • d) The winner is said to win by the number of remaining stones.
8. Chinese half counting for area scoring:
   • a) I is the total number of intersections of the board (I = 361 for a 19x19 board).
   • b) N is the number of empty intersections that do not score.
   • c) H is half the difference of I and N, i. e. H = (I - N) / 2, and the reference point for the half count.
   • d) The black score B is counted.
   • e) First the empty intersections that score for black are counted. Each region of such empty intersections shall assume a shape that represents a multiple of ten. For this purpose one stone at a time may be rearranged. Such a stone is adjacent to a region in question (but not to an opposing region), is taken off the board, and either put in some counted region and adjacent to another stone or put away. When multiples of ten have been properly created, they are added as the sum E of counted empty intersections for black.
   • f) When E is determined the number of black stones on the board has to remain constant. All black stones are rearranged in piles of ten as far as possible. Then the number of black stones S is determined.
   • g) Then B is the sum of E and S, i. e. B = E + S.
   • h) B is compared with H. Black wins if B is greater than H (B > H). White wins if B is smaller than H (B < H). The game is a tie if B and H are equal (B = H).
   • i) The winner is said to win by twice the positive difference of B and H.
9. Point by point counting for territory scoring:
   • a) First the numbers of empty intersections scoring for black respectively white, Eb and Ew, are counted.
   • b) Each count is performed by scanning the intersections of the board using a finger. It denotes any intersections belonging to an according count. The intersections are added.
   • c) The numbers of black respectively white prisoner stones, Pb and Pw are counted.
   • d) Each player's count is the sum of his empty intersections and of opposing prisoner stones, i. e. black's count is B = Eb + Pw, white's count is W = Ew + Pb.
   • e) The winner is the player of the higher count. He is said to win by the positive difference of the two counts. If both counts are equal, then the game is a tie.
10. Japanese counting for territory scoring:
    • a) As far as possible, black prisoner stones are filled in empty regions scoring for black, white prisoner stones are filled in empty regions scoring for white. Remaining black respectively white prisoners are counted as Rb and Rw.
    • b) Then all remaining empty intersections scoring for either player are counted, first black, then white.
    • c) As far as possible, each region of such empty intersections of a player shall assume a shape that represents a multiple of ten. For this purpose one stone at a time may be rearranged. Such a stone is adjacent to a region in question (but not to an opposing region), is taken off the board, and put in some counted region and adjacent to another stone. After proper rearrangement, the remaining empty intersections of a player, black or white, are added as Eb respectively Ew. (During rearrangement stones adjacent to a region should be of the colour for which it scores.)
    • d) The count of a player is the sum of remaining empty intersections counting for him and of remaining opposing prisoner stones, i. e. black's count is B = Eb + Rw, white's count is W = Ew + Rb.
    • e) The player with the higher count wins the game. If both counts are equal, then the game is a tie. The winner is said to win by the positive difference of the two counts.

Komi

1. Before a game its score may be adjusted by a number of points, called komi.
2. Komi is set by the tournament organization.
3. Komi may be
   • a) integer values to allow ties, or
   • b) integer values adjusted by plus 0.5 to avoid ties.
4. Komi is considered for counting and compares with the full count. Half the komi compares with the half count.
5. Currently for even games, integer values for komi typically vary between 5 and 7.

Handicap Stones

1. A tournament system might set handicap stones for a game.
2. The setting might use one of the following types:
   • a) free handicap,
   • b) fixed handicap.
3. Before white plays its first stone, black has to play as many stones as are set as his handicap.
4. Free handicap:
   • a) Alternation of the game starts with black playing H handicap stones and white passing H-1 times in between.
   • b) The empty intersections for the handicap stones may be chosen freely.
5. Fixed handicap:
   • a) Before alternation of the game black puts his handicap on the board. Then white starts alternation.
   • b) From the perspective of the black player, the intersections of the board have coordinates A to T, omitting I, from left to right and 1 to 19 from the bottom to the top.
   • c) For a handicap of H stones the following intersections are occupied:
     • H = 2: Q16, D4.
     • H = 3: Q16, D4, Q4.
     • H = 4: Q16, D4, Q4, D16.
     • H = 5: Q16, D4, Q4, D16, K10.
     • H = 6: Q16, D4, Q4, D16, Q10, D10.
     • H = 7: Q16, D4, Q4, D16, Q10, D10, K10.
     • H = 8: Q16, D4, Q4, D16, Q10, D10, K4, K16.
     • H = 9: Q16, D4, Q4, D16, Q10, D10, K4, K16, K10.

Thinking Times

1. In each game each player uses set thinking times with the aid of proper clocks.
2. If a player exceeds all his allotted time, he loses the game by time exceeding.
3. For a tournament, the tournament organization sets the thinking times.
4. Thinking times consist of a basic time and possibly overtime periods.
5. Basic time should vary between 0 minutes and 10 hours.
6. Lightning games should use between 10 minutes and 1 hour basic time.
7. Normal games should use between 1 and 8 hours basic time, with 3 to 5 hours being most typical.
8. The basic time should reflect the nature of the tournament.
9. Each overtime period requires play of a predetermined number of stones and pressing the clock within a predetermined time limit. Passing includes putting away one stone.

See also

• http://home.snafu.de/jasiek/int.html