[The citation is taken from the English booklet „World Amateur Go Championship - Rules -“, 1980, Nihon Kiin. Diagrams and their references and annotations are omitted.]
The rules of play for the World Amateur Go Championship follow the Nihon Ki-in’s Laws of Go (as established October 2, 1949). In this booklet those of the laws which seem essential to the rules of play have been translated into English for the reference of the players participating in the tournament. However, chapter 7 of the laws (articles 35 - 40) have been revised specifically for this tournament. The revised articles concern the determination of the end of the game (article 35), passing one’s move and subsequently resuming it (article 36), the filling of neutral points (article 39), and defending inside territory (article 40). The new rules appear as 20 - 24 below. The Nihon Ki-in Precedents have also been altered with respect to three points without capturing and defense inside territory.
Go is a game for two players, who compete under fixed terms of play, using a go board and go stones, by playing alternately, on any point on the board (except when restricted by the rules below) to see which can take more territory. After play is completed territory is counted to determine the winner, although in the cases noted in rule 21 the winner may be determined without counting.
Except for matters related to handicaps and the first move, which are decided on the basis of the terms of play in accordance with the players’ strengths, all rules apply equally to both players.
Number of players
The number of players is normally two, but in relay games, consultation games, etc. more than two people may participate.
(i) The go board is a flat surface marked with nineteen parallel vertical and nineteen horizontal lines. The standard board is made of wood and measures approximately 45 cm in the vertical direction and 42 cm in the horizontal direction. Its thickness is about 15 cm and it is supported on four legs. However, the game may be played on boards of non-standard size and material, with or without legs.
(ii) The vertical lines of the board are designated as 1, 2, 3, ...., 19 starting from the left side as seen by the player of the black stones. The horizontal lines are designated as A, B, C, ...., T starting from the top [and omitting I].
(iii) The intersections of the vertical and horizontal lines are called ‘points’. There are 361 points in all. The points are designated as A-1, B-2, T-19, etc. according to the lines on which they lie.
The nine intersections of lines 4, 10, and 16 with lines D, K, and Q are
designated as ‘star points’ in the following order.
1st star point - D-16
2nd star point - Q-4
3rd star point - Q-16
4th star point - D-4
5th star point - K-16
6th star point - K-4
7th star point - D-10
8th star point - Q-10
9th star point - K-10
The 9th star point is also called ‘tengen’ point.
(i) The stones are devices for marking the players’ moves on the board. Normally they are disc-shaped and of two colors, black and white.
(ii) The size of the stones should correspond to the size of the board, being equal to the separation of the vertical lines. For the standard board described in rule 4(i) the diameter of the stones should be approximately 2.2 cm; these are called standard stones.
(iii) There should be 181 black and 180 white stones. Since all will not usually be needed in play, however, the game may be played with a smaller number of stones.
Terms of Play
Terms of play
(i) The terms of play fall into the following types:
Tagai-sen - the players hold black un alternate games
Sen-ai-sen - one player holds black 2 games out of 3
Sen - one player holds black in every game
Sen alternated with a 2-stone handicap
In addition, in certain circumstances a komi may be given.
(ii) If a komi is given, normally 5« points are added to White’s territory when counting at the end of the game to determine the winner (unless the winner has been determined by resignation, as specified in rule 21).
Rules of Play
Order of moves
(i) In non-handicap games Black always makes the first move, then White and so on in alternation, one move at a time.
In handicap games Black begins by placing two or more stones on the star
points as follows.
2-stone handicap: on the 1st and 2nd star points
3-stone handicap: on the 1st through 3rd star points
4-stone handicap: on the 1st through 4th star points
5-stone handicap: on the 1st through 4th star points and tengen point
6-stone handicap: on the 1st through 6th star points
7-stone handicap: on the 1st through 6th star points and tengen point
8-stone handicap: on the 1st through 8th star points
9-stone handicap: on the 1st through 8th star points and tengen point
Then White makes the first move, after which the players alternately make one move at a time.
Placement of moves
Moves are played on the points, and except for the restrictions in rules 12 and 13 the players may play on any vacant point on the board throughout the game.
When, during the game, a player has occupied all but one of the points adjacent to an enemy stone or group of stones, the enemy’s stone or group of stones is said to be in ‘atari’.
When a player plays on the last point adjacent to an enemy stone or group that is in atari as described above, he must remove the enemy stone or group from the board. This is called ‘capturing’.
Stones that have been removed from the board in accordance with the preceding rule are called ‘prisoners’.
Except when capturing enemy stones, a player may not play on the following points.
1) A move surrounded by enemy stones
2) The last remaining vacant point of a connected group of points surrounded by enemy stones, when all the other points of the group have been occupied.
(i) A position in which both players can alternately capture and recapture one stone apiece is called a ‘ko’.
(ii) When a ko arises and a player captures in it, his opponent may not recapture the capturing stone without first playing at least once elsewhere. Such moves elsewhere are called ‘ko threats’. Both players’ moves are equally restricted by this rule.
(iii) The purpose of this restriction is to prevent the endless repetition of the same position that would occur if recapture took place without making ko threats. This is called the ‘principle of prohibition of repetition’.
(iv) In those rare cases of triple or quadruple ko, in ko-like patterns such as eternal life, and in other abnormal positions, the Nihon Ki-in may establish special rules governing the restriction of moves and the end of the game, regardless of the principle of prohibition of repetition. (See the precedents below.)
Life and Death
A point on which a player may not play because of rule 12 is called an ’eye’.
(i) A player possesses an eye at a point when he has occupied at least seven of the eight points surrounding it with his own stones, or when alternate play by both sides would produce such a pattern. However, to possess an eye at one of the corner points (A-1, A-19, T-1, T-19) a player must have occupied, or be able through alternate play to occupy, all three of the points surrounding it, and for an eye at a non-corner point on the edge all five surrounding points are necessary.
(ii) A point which a player has surrounded in a pattern other than those specified in the preceding paragraph and which he cannot bring into one of those patterns through alternate play is called a ‘false eye’.
(i) A group of stones is termed ‘alive’ if it possesses at least two eyes such as specified in paragraph 15(i), or if it can secure at least two eyes for itself through alternate play.
(ii) A group which has two eyes, one or both of which are false, but which cannot be captured because of the restrictions in rule 12 is also alive, the preceding paragraph notwithstanding.
(i) A position in which there are two opposing groups without eyes or with one eye apiece but in which neither side can move first and capture the other is called a ‘seki’.
(ii) In a seki both sides’ stones are considered to be alive.
Groups of stones which possess, or for which alternate play will produce, shapes other than those specified in the preceding two rules are termed ‘dead’.
Those points on the board which a player has surrounded with living stones of his own and on which his opponent cannot live are called ‘territory’. Each such point counts as one point of territory, except that points which are surrounded by stones alive in a seki are not counted as territory.
The End of the Game
Determining the end of the game
(i) The players continue to play alternately until all the neutral points have been filled and all necessary defensive moves inside territory have been made. Then the player whose turn is next declares the end of the game. If his opponent agrees, the game is ended.
(ii) The opponent may however disagree and continue to play, in which case the player who declared the end of the game may also resume play.
Resignation and expiration of time
If during the course of the game either player should admit defeat and abandon play, the game ends and his opponent is declared the winner.
When the game ends as stipulated in rule 20 it is said to have been ‘finished’, and the winner is determined as described in the following rules.
Filling in territory
When the game is finished, each player removes any dead enemy stones that are surrounded by his own live stones, adds them to the prisoners mentioned in rule 11, and uses these to fill in his opponent’s territory.
Prisoners in seki
If there are enemy stones inside an eye possessed by a group that is alive in seki, the player may capture them, force his opponent to play as many additional stones as necessary, and capture them also, adding them to his prisoners, as long as this does not destroy the seki pattern.
Rearrangement of territory
Next the players rearrange their opponent’s territory into shapes convenient for counting. This is called ‘rearranging the territory’.
(i) After rearranging the territory as described above, the total amount of both sides’ territory is compared. The player with more territory is the winner, his opponent is the loser, and the winner is said to have won by the difference in territory. When both sides have the same amount of territory, the game is a draw.
(ii) If after filling in his opponent’s territory a player has still prisoners left, their number is added to his territory when counting.
(iii) In a komi game that is counted as in paragraph (i) above, the amount of the komi is added to the territory of the side receiving it.
Questions, Precedents, and Rulings
Questions that arise concerning rule 13(iv), concerning life, death, and seki, concerning whether or not it is necessary to defend inside one’s territory, concerning the counting of territory, etc. are to be settled in accordance with the Nihon Ki-in’s precedents given below.
If in any of the above cases no precedent exists, the question shall be ruled upon by the Nihon Ki-in.
Nihon Ki-in Precedents
Ko questions and three points without capturing
(1) A bent four in the corner is independently dead, regardless of the rest of the board.
(2) The three-points-without-capturing positions shown are to be resolved by actual play. If neither captures, neither receives any territory.
(3) If a triple, quadruple, quintuple, etc. ko, a round-robin ko, an eternal life, or other abnormal pattern arises and the same board position is made repeatedly with neither side willing to give in, the game ends without result.
(4) In a thousand-year ko, if neither side is willing to start the ko, the player who is able by capturing and connecting to make the position a seki shall do so.
Defensive moves inside territory
All questions concerning the need for defense inside territory are to be resolved by actual play, with a pass regarded as one move.