Komidashi

Komi points are compensation points given in the game of go to one player to add to his or her score. Komidashi is the more complete Japanese language term, Ho-Sun 호선 in Korean.

History

White is at a disadvantaged due to the fact it plays second. The importance of playing first has not been noticed until 1930s. History shows that the winning percentage of Black is more than White. This somewhat prove the importance of first move.

The compensation (Komi) system was introduced into professional go in Japan as a gradual process of innovation, beginning in the 1930s. The correct value of komi to set has been re-evaluated over the years, as professional opening strategy has evolved.

This value has varied widely over the years. At first, it started at as low as 2.5 points. It kept moving up to 4.5 and then 5.5. 5.5 points had once been used for a long time. Until recently, researches shows that 5.5 points are still a bit insufficient to compensate White's disadvantage. It is then raised to 6.5. Some use as high as 7.5 points.

Comments on compensation system

Fairness of compensation points

It is hard to determine the best and fairest value of compensation points. However it is thought playing first is equal to about half a move (or a bit more) ahead throughout the game.

Although the generally acceptable compensation points nowadays are 6.5 points; each country, association, and tournament may set its own specific compensation points:

In Japan, the usual komi in Japan was once started at about 2.5 points. For some time later, it is raised to 4.5 points. In 1955 the Oza became the first tournament to adopt 5.5. 5.5 has been used for a long time afterward until the Nihon Ki-in decided to change to 6.5 in September 2002.
In Korean, it used to be 5.5, but is switched to 6.5 now.
In China, the usual compensation point was 5.5, but 7.5 is now standard.
In America, American Go association (AGA) official rules still specify 5.5 points, however they suggest also experimenting with values up to 8.5 points in both informal games and tournaments in order to gather data to determine the effects of increasing U.S. komi officially.
The New Zealand rules specify a komi of 7. The American Go Association changed komi from 5.5 to 7.5 in August 2004, effective 2005. John Fairbairn has written on the History of Komi.
For Ing Foundation, the Ing rules also have a compensation point of 7.5, specified as 8 points with Black winning draw.

Justification of half point value

The rationale behind the half point in is to prevent a drawn game.

Some argue there is nothing wrong to have a draw, considering a game could theoretically end in a draw this way. Not allowing a draw seems to skew the actual skills between 2 players by forcing either one to win (while there is no winner or loser indeed). There is however a hidden parity question which means that a draw is unlikely. Lately, the Ing Cup have been using an 8 point komi rule in their tournament.

Neverthelss, due to several reasons like convenience for most common tournament formats, the extra efforts in holding rematches, human nature of liking to always have a winner in a game; the use of half point is prevailing.

Type of Compensation System

Fixed compensation point system

By far the most common type of komi is fixed compensation point system. A fixed points, determined by the Go organization or the match organizer, is given to the second player (White) in an even game (ie without handicaps) to make up for first-player (Black) advantage.

When ranks are equal, compensation points (komi) are necessary to offset the advantage of being black (moving first). There are still no absolute standards on the number of compensation points due to the difficulty of determining a fair value. 6.5 points are used in Japan and Korea. 7.5 points are used in China and America (see AGA rules). 0.5 is used to prevent a draw.

Auction compensation point system

As no one can be absolutely sure what is the fair number of compensation points, some advocate another system which is often used in some amateur matches and tournaments. There is no fixed compensation points. The decision is left to both players. They arrive at a value through negotiation and bidding. This is called auction compensation point system.

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