Proposal by Robert Jasiek. Version 1. 2008-11-24.
Original Rules: World Mind Sports Games 2008, English version, 2008-07-15; supplementary ko rule.
1. The board is a grid of 19 evenly-spaced parallel vertical lines and 19 evenly-spaced parallel horizontal lines. They form 361 intersections.
2. There are black and white stones.
3. There are two players: one takes the black stones and the other the white stones. They are respectively called Black and White.
1. The board is initially empty.
2. Black makes the first play by placing a stone on an empty intersection of the board, then White, and so on in alternation.
3. Playing alternately is the right of both players, but either player may give up the right to make a play and this is known as a pass.
1. The empty intersections that are immediately adjacent to a stone along horizontal or vertical lines are called the liberties of that stone.
2. A set of same-color stones that are connected along the lines form a unit, and the empty intersections adjacent to the unit are the liberties of that unit.
3. A stone or the stones of a unit left with no liberties are removed from the board.
4. After a player places a stone and leaves stones or units of stones of both sides with no liberties, the stones of this player remain on the board and the stones of the opponent are removed.
5. A player may not play on an empty intersection so that then that stone and its connecting unit of stones would be without liberties, while failing to remove any of the opponent’s stones.
It is illegal to play in such a way as to recreate a board position that previously existed on the board.
After the first succession of two passes, one of the following happens:
1. The two players make a mutual agreement on which stones to remove and remove them. Afterwards the game end is reached.
2. One or both players propose to resume alternation. They continue in the original order to the second succession of two passes. Afterwards the game end is reached.
1. The goal of a Go game is to have the favourable score at the game end.
2. At the game end, all the intersections occupied by the stones of a player together with all the empty intersections surrounded by these stones constitute that player's points. The empty intersections between black stones and white stones are divided evenly between the two players.
3. There are two types of compensations. The first type depends on who passes first in the game. If White passes first, Black's total points are reduced by 1. If Black passes first, no such compensation is given.
4. The second type of compensation is an amount that reduces Black's total points. This is called the komi.
5. The difference between the two players’ points on the board, corrected for compensations, determines the score.
1. As a visual assistance, the nine intersections traditionally called “star points” are dotted.
2. Lens-shaped black and white stones are used, with a size slightly smaller than an element of the grid. The numbers of stones should be adequate to last until the game end. In official competitions, the numbers shall be at least 180 for each color.
After a stone is placed on an intersection, it shall not be moved to any other intersection.
By default, the amount of komi is 6.5 points. A different amount may be announced for a competition.
1. For a competition, the used method for counting is announced.
2. There are different but equivalent methods for counting. The following are the most widely spread methods.
3. "counting the stones and the surrounded points", also called Chinese Counting: 1) perform Chinese Half Counting of the position, 2) double the count, 3) subtract the komi, 4) subtract any White passes first compensation.
4. "counting the surrounded points after filling in the prisoners", also called Japanese Counting. It is well known that pass stones and an equal number of valuable moves (a move is a play or a pass) are required. Therefore 1) for each pass during the game, a player takes 1 stone from his bowl and adds them to the removed stones (prisoners), 2) however, if Black has made the very last pass of the game, then for that pass the payment in (1) is not done, 3) Japanese Counting (including all prisoners and pass stones) is performed, 4) subtract the komi, 5) subtract any compensation if White has made the game's first pass.
5. "counting by filling in all the stones": This refers to Ing Counting. This method requires that both sides start with exactly 180 stones each, which should be ascertained before the game. 1) Ing Counting is performed, 2) subtract the remaining fraction 0.5 of the komi, 3) subtract any White passes first compensation.
Either player may resign during the game, in which case the game end is reached immediately.
The players may resume alternation only to "confirm" the "life" or "death" of stones and the "rights to the empty intersections" enclosed by the stones having "life". If one or both players correctly denote other "contestable intersections" on the board after the first succession of two passes, those intersections shall be left as they stand and are evenly divided between the two players.
A player may not pass if
there is at least one ko with his ko stone on the board that is neither a disturbing life nor an internal disturbing death and
he has some legal play that is not on a two-eye-formation.
The first type of compensation aims to balance the advantage of one excess play by Black until the game's first pass.
The second type of compensation aims to balance the advantage enjoyed by the player who makes the first play. To ensure a fair game, Black is asked to deduct an amount from his total points, traditionally known as the komi (tie-xian in Chinese).
The stones removed by plays become prisoners. The stones removed by mutual agreement after the first succession of two passes are dead and added to the prisoners. All the stones remaining on the board at the game end are alive.
The most common example of a prohibited recreated board position is a ko (jie in Chinese), where capture and immediate recapture of a single stone would recreate the board position. In such a case, after a player makes a capture, his opponent may not make a capture immediately, as this would repeat the board position before the first player’s capture. Instead, the opponent must make a play elsewhere on the board. When both players, after playing away, make repeated captures in such a formation, this process is known as a ko fight. The play away from the ko itself is known as a ko threat.
A cyclic ko happens when three or more kos appear simultaneously or when other repetitive situations involving multiple stones, such as “eternal life”, occur. The principle for handling them is always the same: before placing a stone that would cause a repetition of the board position, the player must play away from the repetitive cycle.
Usually two successive passes signal that both players think that there are no more points to contest for in the game. The game of placing the stones in alternation comes to a preliminary stop. Usually the competition is over.
Mistakes are corrected. Exception: Some terms and concepts in the optional cultural rules could not be defined by rules experts yet.
Clarity of the wording has been increased. The possibility for correct and precise translation has been eased.
Figures have been omitted because it would be counter-productive to provide figures for trivial aspects but none for more difficult aspects.
Unless stated otherwise, rules changes have been restricted to a minimum.
The terms in the optional supplementary ko rule are defined but elsewhere. Otherwise the length of these rules would be doubled and only theoreticians could still understand them.
The terminology has been made consistent. E.g., a point is always a value unit and never an intersection. E.g., an empty intersection is always empty and never vacant or unoccupied. This consistency should ease understanding.
In the rules, "ko" refers to two adjacent intersections on that in principle a succession of two plays could recreate the board position.
Rules that by their nature are tournament rules are moved to the appropriate section. The same applies to optional rules and strategic commentary. Separation of the rules of play from tournament rules and official strategic commentary allows a clear view on how concise the rules of play are. Besides essential versus optional parts can be identified easily.
Instead of superko, various other sets of ko rules or overriding tournament rules could be used. However, always such changes revert to the same question: Why not just use the shortest rule? Some players' difficulty with its application can be answered by strategic commentaries.
The procedure to the game end is simple and clear. One must not repeat a frequent mistake of rules writing though: to hide the procedure amidst the fog of commentary and superfluous exceptions.
To play on a 1-sided dame after the first succession of two passes, a player proposes to resume alternation. Therefore exceptional rules for 1-sided dame are not needed.
In the core of the rules of play, the first pass compensation is the only new rule.
There are these general advantages:
It is an elegant compromise between Area Scoring and Territory Scoring.
It allows counting procedures of either scoring system.
This advantage of Area Scoring is maintained:
The simple, clear, and complete definition of Area Scoring is used.
These advantages of Territory Scoring are maintained:
The smallest regular score difference is 1 point.
2-sided dame are unvaluable.
It is strategically correct to make the game's first pass before the final removals.
It is strategically correct to make the game's first pass before superfluous defensive plays.
These disadvantages are created:
A few late endgames show a new behaviour.
The Japanese counting procedure for Territory Scoring requires usage of pass stones.
The counting procedures are described with greater detail and liberality. In particular, Japanese Counting is spelled out carefully. E.g., New Zealand Half Counting is not prohibited.
The author recommends to drop the optional cultural rules. Functionally they are superfluous. Even top rules experts do not fully understand them. If one cannot do without such cultural reference, it should be put into the official strategic commentary.
The supplementary ko rule has the advantage to eliminate the first pass compensation's disadvantage of new behaviour in a few late endgames. The price is high though: It required detailed research to understand why hopefully the current wording of the supplementary ko rule is the closest approximation to its intention. Application as a rule is difficult. Fortunately, in almost all practically occurring games, intuitive application is easy for experienced tournament players.
It is another frequent mistake to use the terms alive and dead in the rules of play when in reality they are strategic concepts. This would create confusion and ambiguity. Therefore the two terms and moved to the official strategic commentary.