Gomoku

Gomoku is an abstract strategy board game. Also called Gobang or Five in a Row, it is traditionally played with Go pieces (black and white stones) on a go board with 19x19 (15x15) intersections; however, because pieces are not moved or removed from the board, gomoku may also be played as a paper and pencil game. This game is known in several countries under different names.

Black plays first if white did not win in the previous game, and players alternate in placing a stone of their color on an empty intersection. The winner is the first player to get an unbroken row of five stones horizontally, vertically, or diagonally.

It originated in Japan during the Heian period. The name "Gomoku" is from the Japanese language, in which it is referred to as gomokunarabe (五目並べ^?). Go means five, moku is a counter word for pieces and narabe means line-up. The game is also popular in Korea, where it is called omok (오목 [五目]) which has the same structure and origin as the Japanese name.

The Japanese call this game Go-moku (five stones). In the nineteenth century, the game was introduced to Britain where it was known as Go Bang, said to be a corruption of the Japanese word goban, said to be adopted from Chinese k'i pan (qí pán) "chess-board."

Besides many variations around the world, the "Swap2" rule (based on "swap" from Renju) is currently adapted in tournaments among professional players. The first player places 3 stones (2 black 1 white, if black goes first) on the board, the second player has the choice to take black/white or to place 2 more stones to change the shape and let the first player choose color. This is essentially a slightly more elaborate pie rule.

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