Go (board game)

Go is a strategic, two-player board game originating in ancient China between 2000 BC and 200 BC.

Nature of the game

Although rules of Go can be written so that they are very simple, the game strategy is extremely complex. Go is a complete-knowledge, deterministic, strategy game: in the same class as chess, checkers (draughts), and reversi. Its depth arguably exceeds even those games. Its large board and lack of restrictions allows great scope in strategy. Decisions in one part of the board may be influenced by an apparently unrelated situation, in a distant part of the board. Plays made early in the game can shape the nature of conflict a hundred moves later.

Related Topics:
Complete-knowledge - Deterministic - Strategy game - Chess - Checkers - Reversi

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The game emphasises the importance of balance on multiple levels, and has internal tensions. To secure an area of the board, it is good to play moves close together; but to cover the largest area one needs to spread out. To ensure one does not fall behind, expansionist play is required; but playing too broadly leaves weaknesses undefended that can be exploited. Playing too low (close to the edge) secures insufficient territory; yet playing too high (far from the edge) allows the opponent to invade. Many people find the game attractive for its reflection of polarities also found in life.

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See Go strategy and tactics for an introductory explanation of how to play well.

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It is commonly said that no game has ever been played twice. This may be true: On a 19×19 board, there are about 3361×0.012 = 2.1×10170 possible positions, most of which are the end result of about (120!)2 = 4.5×10397 different (no-capture) games, for a total of about 9.3×10567 games. Allowing captures gives as many as

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:10^{7.49 imes 10^{48}}

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possible games, most of which last for over 1.6×1049 moves! (For two comparisons: the number of legal positions in chess is estimated to be between 1043 and 1050; and physicists estimate that there are not more than 1090 protons in the entire visible universe.)

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