Rules of Go

Rules Of Igo

This is an in-depth discussion of the rules of go.

There has been a certain amount of variation in the rules of go 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. (Traditional Himalayan variants, including Tibetan go, differ more markedly and are discussed instead in the article Go variants.) Even among these, there is a degree of variation.

Notably, Chinese and Japanese rules differ in a number of respects. The most significant of these is 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.

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

Basic rules

One black chain and two white chains, their liberties shown with dots. Note that liberties are shared among all stones of a chain.

Two players, Black and White, take turns placing a stone (game piece) of their own color on a vacant point (intersection) of the grid on a Go board. Black moves first. (If there is a large difference in strength between the players, Black is sometimes allowed to place two or more stones on the board for his first move, see Go handicaps for details). The official grid comprises 19×19 lines, though the rules can be applie

d to any grid size; 13×13 and 9×9 are popular choices to teach beginners. Once played, a stone may not be moved to a different point.

Vertically and horizontally adjacent stones of the same color form a chain (also called a group) that shares its liberties (see below) in common, cannot subsequently be subdivided, and in effect becomes a single larger stone. Only stones connected to one another by the lines on the board create a chain; stones that are diagonally adjacent are not connected. Chains may be expanded by playing additional stones on adjacent intersections or connected together by playing a stone on an intersection that is adjacent to two or more chains of the same color.

If white plays at A, the black chain loses its last liberty. It is captured and removed from the board.

A vacant point adjacent to a stone is called a liberty for that stone. Chains of stones share their liberties. A chain of stones must have at least one liberty to remain on the board. When a chain is surrounded by opposing stones so that it

has no liberties, it is captured and removed from the board.

Most rule sets do not allow a player to play a stone in such a way that one of their own chains is left without liberties, subject to the following important exception. The rule does not apply if playing the new stone results in the capture of one or more of the opponent's stones. In this case, the opponent's stones are captured first, leaving the newly played stone at least one liberty.The rule just stated is said to prohibit suicide. (Since suicide is very rarely useful, making it legal does not significantly alter the nature of the game.)

An example of a situation in which the ko rule applies

Players are not allowed to make a move that returns the game to the position before the opponent's last move. This rule, called the ko rule (from the Japanese 劫 kō "eon"), prevents unending repetition.See the example to the right: Black has just played the stone marked 1, capturing a white stone at the intersection marked with a circle. If White were now allowed to play on the marked intersection, that move would capture the black stone marked 1 and recreate the situation before Black made the move marked 1. Allowing this could result in an unending cycle of captures by both players. The ko rule therefore prohibits White from playing at the marked intersection immediately. Instead White must play elsewhere; Black can then end the ko by filling at the marked intersection, creating a five-stone Black chain. If White wants to continue the ko, White will try to find a play that Black must answer; if Black answers, then White can retake the ko. A repetition of such exchanges is called a ko fight.

While the various rule sets agree on the ko rule prohibiting returning the board to an immediately previous position, they deal in different ways with the relatively uncommon situation in which a player might recreate a past position that is further removed. See Rules of Go: Repetition for further information.

Instead of placing a stone, a player may pass. This usually occurs when they believe no useful moves remain. When both players pass consecutively, the game ends and is then scored.

Introduction igo

Go is a strategic board game for two players. Also known as igo (Japanese), weiqi or wei chi (Chinese) or baduk (korea). Go noted for being rich in strategic complexity despite the simple rules.

Like a chess game played by two players who alternately place black and white stones (play fruits, now usually made of glass or plastic) at the intersection of a box of empty 19 × 19 rows. The purpose of this game is to control a larger portion of the board than your opponent. A stone or group of stones that were captured and removed if it does not have an empty adjacent intersection, the result is completely surrounded by stones of the opposite color.

Placing stones close together helps them support each other and avoid capture. On the other hand, placing stones far apart creates more influence on the board. Part of the strategic difficulty of the game comes from finding a balance between conflicting interests like that. Players strive to serve both defensive and offensive purposes and choose between tactical urgency and strategic plans.

Go originated from ancient China over 2,500 years ago, and although it is not known exactly when the game was created, in the 3rd century BC it had become a popular hobby, as indicated by the reference to the game in the Analects of Confucius. Archaeological evidence indicates that the initial game is played on a board with 17 × 17 grid, but at the time that the game spread to Korea and Japan at approximately the 7th century to the board 19 × 19 grid has become the standard.

The most popular game in East Asia, but has gained some popularity in other parts of the world in recent years. A conservative estimate places the number of go players in the world at around 27 million. Go to reach the West through the Japanese, which is why it is generally recognized internationally by the Japanese name.