Go handicap

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In an even game of Go, the board is empty, and Black plays first. The advantage of that first move is compensated by komi. In a handicap game, the weaker player takes Black, but has an appropriate number of stones on the board before play starts. White then plays first.

The handicap allows for players of varying strengths to have balanced games and is based on the difference in strengths (ranking) between the players. For example, an 8 kyu (weaker) player would take 3 handicap stones against a 5 kyu (stronger) player. A 2 dan (weaker) player would take 3 stones against a 5 dan (stronger) player.

On a 19 x 19 go board there are nine handicap points marked on the board - in each corner on the (4,4) point, in the middle of each side on the fourth line, the (4,10) point, and the very center of the board, (10,10). Odd handicaps use the center stone (apart from three stones), even handicaps do not. A handicap of two or three stones uses opposite corners; in Japan the third stone in a three-stone handicap is at (4,4) by Black's right hand, while in China it has traditionally been at the center. Four or more stones uses all four corners. Six or seven stones uses opposite sides. Eight or nine stones use all four sides.

Placement of the handicap stones is explained on this Senseis webpage.

Another type of handicap is the reverse komi or gyaku komi, where the weaker player takes black, and is given both the first move and some compensation points, usually 5 1/2 to 7 1/2 points (moku). See Go rules for more on komi.

The correct handicap therefore includes both methods: intitial placement of stones + (reverse) komi, resulting in this rating-difference-correlation:

On smaller go boards (most common are 13 x 13 and 9 x 9), the handicap is reduced proportionally according to the number of points on the board. For example, if the difference in rank (handicap) is 8 stones on a 19 x 19 board (361 points), the handicap is reduced to 4 stones on a 13 x 13 board (since the area of the board--169 points--has been approximately halved) and 2 stones on a 9 x 9 board (81 points or approximately one-quarter). Smaller boards are typically used for beginners learning the game.ja:置き碁 pl:Handicap (go) zh:讓子