Go (board game)

(CC) Photo: S. Venga
Modern game board of Go the game.

Go is a board game played by two players. It is also referred to as Weiqi in Chinese (圍棋; 围棋), Baduk in Korea (바둑) and Igo or Go in Japanese (囲碁; 碁). Go is the world's oldest game that is played in its original form, with a documented history of over 2,500 years.

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Character

Go is played on a flat board with a grid of 19x19 intersections. Two sets of white and black stones are used. The game is played in turns and unlike Chess, black makes the first move in go. Each stone is placed on an intersection and the goal is to capture more territory than the opponent. In go, it often matters whether a given move is beautiful or produces good shape.

It is possible to play essentially the same game on a board of size different from the standard 19 by 19. Beginners, children and those in a hurry, often play on 13 by 13 board, or even on 9 by 9.

Rules

There are a few different Rule Sets for playing Go. They are very similar to each other and for most games the different rules give similar results. The core rules are:

1. Each turn a player places a stone on one empty intersection. Afterwards it's the other player's turn.

2. A stone is a member of a group of stones if one stone is connected to another stone of the group with the same color via a line (there are no direct diagonal connections). If there is no stone that is connected via a line to an empty intersection in a group that group is dead and has to be removed from the board and the stones become prisoners.

3. You aren't allowed to make a move that directly reverses the move of your opponent (your move would remove the stone of your opponent and that stone closed the last intersection of one of your stones and you want to replay that stone).

4. If nobody wants to make a move and passes the game is over. All stones that could be captured through adding additional stones are dead and get removed from the board and become prisoners.

After Japanese rules the winner is the person whose sum of enemy prisoners together with the amount of empty intersections that surround his stones is greater than the other person's.

In Chinese rules you add the number of your stones to the number of your surrounded empty interactions and the player that has the most points wins.

Because making one prisoner reduces the amount of enemy stones exactly by one both methods usually get the same result, besides the fact that in half of the games there is a one point difference because white passed first and black played one stone more than white.

While the above rules are sufficient for most games, specific rules that exactly define the terms that are used in the rules can be a bit longer.

Also see Go rules.

History

There is no exact date for the invention of Go. One legend dates the invention to the Emperor Yuo who taught the game to his eldest son Dan Zhu. Most modern writers think, that this legend (and a few similar legends), were written down in the Han period, to make the game appear older than it really is. They date the invention to the period of 1000-400 BC.

Comparison to chess

Go is conceptually simpler than chess (especially when go rules are properly formulated):

• A go player has only one kind of pieces, called stones. A chess player has six kinds of pieces (king, queen, rook, bishop, knight, pawn, and one of her/his bishops runs on white squares, while the other one on the black--thus they are actually different too).

• A go player makes only one kind of moves, namely setting a stone on an intersection point (the effect may be different each time, causing sometimes a group of opponent stones to be removed). A chess pawn has four kind of moves: 1.going one step forward, 2.going two steps forward from its initial position, 3.capturing an opponent's piece one step askew from it and landing where the opponent's piece was, 4. capturing opponent's pawn en passant. On the top of it, the pawn, which reaches the last row gets promoted.

• Go has essentially only one (very natural) restriction on moves: a move which would lead to a repetition of position is illegal (not allowed). It has also another rule, which disallows a suicide, but it's only a cultural rule, not essential to the game. In chess too we have a cultural rule which disallows to put your own king in check. In addition, we have also several essential rules which contribute to the total chess rules complexity: castling, en passant, promotion and the rules about draw by repetition or by making 50 moves by both sides without any capturing and without any pawn move, or by stalemating your opponent.

Chess as a whole does not admit any natural, regular generalizations onto larger boards (but many chess endings do). In the case of go, one may play the game on the square boards of arbitrary n by n size, and also on rectangular m by n boards. More than that, one may play go on arbitrary finite simple graphs. Thus go is so mathematical that it provides a graph invariant: with arbitrary graph we may associate the result of the game played optimally by both players (mathematical theory of games states that such optimal strategies exist; it's a corollary to the respective Zermelo's theorem, 1913).

Go is one of the most complex games in the world, far outweighing games such as chess in the number of possible game positions. Indeed, computer chess programs, by year 2000, became as strong or even stronger that the strongest (human) chess players. On the other hand, computer go programs don't have a chance even against go prodigies so far.

Major Titles

There are 7 major go titles in Japan. The record for winning the most titles over the years is held by Japanese professional Cho Chikun, who has won 71 titles.

Tournament	Prize money	Current title holder
Judan		Cho Chikun
Tengen		Kono Rin
Oza		Yamashita Keigo
Meijin		Takao Shinji
Gosei		Cho U
Honinbo		Takao Shinji
Kisei		Yamashita Keigo

Cultural Dimensions

Go strategy is also studied as an metaphor for Asian strategy compared to western strategy.

Neuroscience Research

Neuroimaging research suggests players use the right hemisphere of their brain while playing Go, responsible for position and orientation, slightly more than the left side. The game requires a more global strategy than chess, and thus differs from the more left hemisphere activated activity of playing chess. A study of six subjects suggests successful Go playing requires practice and experience rather than sheer intellectual ability. Another study suggests the ability of professional Go players to assess visual information and nonmotor learning memory processes is mediated in part by the cerebellum and precuneus.