Rules of Go


The rules of Go govern the play of the game of Go, a two-player [|board] game. The rules have seen some variation over time and from place to place. This article discusses those sets of rules broadly similar to the ones currently in use in East Asia. Even among these, there is a degree of variation.
Notably, Chinese and Japanese rules differ in a number of aspects. The most significant of these are the scoring method, together with attendant differences in the manner of ending the game.
While differences between sets of rules may have moderate strategic consequences on occasion, they do not change the character of the game. The different sets of rules usually lead to the same game result, so long as the players make minor adjustments near the end of the game. Differences in the rules are said to cause problems in perhaps one in every 10,000 games in competition.
This article first presents a simple set of rules which are, except for wording, identical to those usually referred to as the Tromp–Taylor Rules, themselves close in most essential respects to the Chinese rules. These rules are then discussed at length, in a way that does not assume prior knowledge of Go on the part of the reader. The discussion is for the most part applicable to all sets of rules, with exceptions noted. Later sections of the article address major areas of variation in the rules of Go, and individual sets of rules.

Basic rules

A set of rules suitable for beginners is presented here. The rules are studied more fully in below.
Two statements of the same basic rules, differing only in wording, are given here. The first is a concise one due to James Davies. The second is a formulation of the basic rules used for expository purposes in this article.
Except for terminology, the basic rules are identical to the Logical Rules first proposed in their current form in September 1996 by John Tromp and Bill Taylor. They are also quite close to the Simplified Ing Rules of the European Go Federation, the only exception being the method of ending the game.

Concise statement

These rules appear in "The Rules and Elements of Go" by James Davies. They assume familiarity with the equipment used to play Go, for which one may refer to below.
Notes: The words [|move] and territory are used differently here than elsewhere in this article; play and [|area], respectively, are used instead. A clarification to rule 5 is added in parentheses.
  1. The board is empty at the onset of the game.
  2. [|Black] makes the first move, after which White and Black alternate.
  3. A move consists of placing one [|stone] of one's own color on an empty [|intersection] on the board.
  4. A player may [|pass their turn] at any time.
  5. A stone or solidly [|connected] group of stones of one color is captured and removed from the board when all the intersections directly [|adjacent] to it are occupied by the enemy.
  6. If a stone or solidly connected group of stones of one color is enclosed and will eventually be captured, they are removed as captured at the end of the game.
  7. No stone may be played so as to recreate a former board [|position].
  8. Two consecutive passes end the game.
  9. A player's area consists of all the [|points] the player has either occupied or [|surrounded].
  10. The player with more area wins.
These rules rely on common sense to make notions such as "connected group" and "surround" precise. What is here called a "solidly connected group of stones" is also called a chain.

Players and equipment

  • [|Rule 1]. Players: Go is a game between two players, called Black and White.
  • [|Rule 2]. Board: Go is played on a plain grid of 19 horizontal and 19 vertical lines, called a board.
  • * [|Definition]. A point on the board where a horizontal line meets a vertical line is called an intersection.
  • [|Rule 3]. Stones: Go is played with playing tokens known as stones. Each player has at their disposal an adequate supply of stones of the same color.

    Positions

  • [|Rule 4]. Positions: At any time in the game, each intersection on the board is in one and only one of the following three states: 1) empty; 2) occupied by a black stone; or 3) occupied by a white stone. A position consists of an indication of the state of each intersection.
  • * Definition. ' Two intersections are said to be adjacent if they are connected by a horizontal or vertical line with no other intersections between them. Note that intersections which are one away from each other diagonally, i.e., intersections that are connected by one horizontal and one vertical line, are not considered adjacent.
  • * Definition. ' In a given position, two placed stones of the same color are said to be connected if it is possible to draw a path from one intersection to the other by passing through only adjacent intersections of the same state.
  • * Definition. In a given position, a liberty of a placed stone is an empty intersection adjacent to that stone or adjacent to a stone which is connected to that stone.

    Play

  • [|Rule 5]. Initial position: At the beginning of the game, the board is empty.
  • [|Rule 6]. Turns: Black moves first. The players alternate thereafter.
  • [|Rule 7]. Moving: When it is their turn, a player may either pass or play. A play consists of the following steps :
  • * [|Step 1]. Placing a stone of their color on an empty intersection. It can never be moved to another intersection after being played.
  • * [|Step 2]. Removing from the board any stones of their opponent's color that have no liberties.
  • * [|Step 3]. Removing from the board any stones of their own color that have no liberties.
  • [|Optional Rule 7A]. ''Prohibition of suicide: A play is illegal if one or more stones of that player's color would be removed in Step 3 of that play.''
  • [|Rule 8]. Prohibition of repetition: A play is illegal if it would have the effect of creating a position that has occurred previously in the game.

    End

  • [|Rule 9]. End: The game ends when both players have passed consecutively. The final position is the position on the board at the time the players pass consecutively.
  • * Definition. ' In the final position, an empty intersection is said to belong to a player's territory if all stones adjacent to it or to an empty intersection connected to it are of that player's color.
  • * Definition. it belongs to that player's territory; or 2) it is occupied by a stone of that player's color.
  • * Definition. ' A player's score is the number of intersections in their area in the final position.
  • [|Rule 10]. Winner:''' If one player has a higher score than the other, then that player wins. Otherwise, the game is a draw.

    Comparative features of the basic rules

The essential features of these basic rules relative to other rulesets are summarized here. Each of the differences is discussed in greater detail in a later section of the article.
What variation exists among rulesets concerns primarily Rules 7A, 8, 9 and 10.
  • The basic rules use area scoring, as in China and Taiwan, and as in the official rules of many Western countries. The main alternative is territory scoring. Though territory scoring is the system used in Japan and Korea, and is customarily used in the West, it is not possible to use territory scoring unless Rule 9 is replaced by a much more complex end-of-game rule. The goal of these basic rules is to present a simple system first. See below.
  • The basic rules require the players to "play the game out" entirely. Virtually all rulesets used in practice provide some mechanism that allows players to begin scoring the game before the final position has been reached. In some cases, this is merely a convenience intended to save time. In others, it may be an essential feature of the game. In any case, explaining these rules might obscure the nature of the game somewhat for a person unfamiliar with it. See below.
  • The basic rules allow suicide. This is unusual outside of Taiwan and New Zealand. Inclusion of Optional Rule 7A is in line with practice elsewhere. See below.
  • The basic rules apply the rule of positional superko. This, or a similar rule, is common in official Western rulesets, but not in East Asia. See below.
  • The basic rules do not contain any special exceptions for territory in a seki. This agrees with most practice outside Japan and Korea. See below.
  • The basic rules do not have a komi. This is now unusual in even-strength games, but was common practice until the mid-twentieth century. A komi is a number of points, usually five to eight, awarded to [|White] in compensation for moving second. See below.
  • The basic rules make no provision for the use of handicap stones. See below.
  • The basic rules do not specify a counting system. A counting system is a conventional method for calculating the difference in score between the players. It may incorporate various devices, such as filling in one's territory after the game, or shifting stones on the board into patterns, which allow quicker calculation of the difference in scores.

    Explanation of the basic rules

The object of the game of go is, in rough terms, to control more territory at the end of the game than one's opponent does.

Elements of the game

Players

Rule 1. Go is a game between two players, called Black and White.
The choice of black or white is traditionally done by chance between players of even strength. The method of selection is called nigiri. One player takes a handful of white stones; the other player then places either one or two black stones on the board, indicating "even" or "odd". Player A counts the number stones in their hand to determine whether there is an odd or even number. If the number of stones matches the other player's selection of "even" or "odd", Player B will play the black stones; if not, they will take the white stones.
When players are of different strengths, the weaker player takes black. Black may also pre-place several handicap stones before play begins, to compensate for the difference in strength—see below.