To play Go, one player places black stones and the other places white stones on a ruled board, traditionally made of carved wood, that forms a grid of 19x19 intersecting lines. There are 361 stones (181 black and 180 white) -- just enough for each of the board's 361 intersections. Smaller boards may be used -- for example, a 9x9 grid is enough to illustrate the basics of the game to beginners, and a 13x13 grid can provide a quick-play version of the game [source: Kiseido].
Players begin a game of Go with an empty board. The black-stone player places the first stone on the board at the intersection of any two lines. The players then alternate turns -- or pass without playing a stone if they wish -- as they attempt to control the majority of the board's territory (intersections) by setting up solid perimeters with their stones, and by preventing their opponent from doing the same by invading their opponent's territory and surrounding (thus capturing) their opponent's stones.
A stone can only be placed on an empty intersection and cannot be moved after it is played -- unless it is captured and taken off the board. A stone can be captured when its player cannot place another stone next to it because it is surrounded by opposing stones. The game ends when both players pass consecutively.
There are two main ways of determining scores in Go: Chinese (or area) scoring and Japanese (or territory) scoring. In Chinese scoring, points are calculated by adding the number of stones you have on the board to the number of empty intersections that your stones surround. In Japanese scoring, points are calculated by subtracting the number of your stones that were captured from the number of empty intersections that your stones surround. In both methods, the player with the highest number of points wins the game [source: Baduk.org, Online Go Server].
To level the field, players can institute the komidashi rule and award free points to the player with white stones. This helps even the score because the player with black stones made the first move of the game. Additional handicaps can be instated based on a player's professional or amateur rank; this allows players to compete even if they have different skill levels.
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