Life In 19x19

magic wrote:Has there ever been studied which komidashi leads to a win/loss rate for white that is the closest to 50/50 when two equally good players play against each other?

In September 2005, the Nihon Ki-in carried out a survey of 1,042 completed games at the new 6.5 komi. It found that Black had won 50.51% and White 49.49%. This was the nearest to parity ever achieved. The equivalent figures in the Nihon Ki-in's last survey under 5.5 komi showed Black won 52.42%.

Figures from Japan in 2008 showed that the latest komi of 6.5 still leaves Black a slight edge. In 19,702 games from 6 November 2002 up to 31 December 2007, Black won 50.59% and White won 49.41%. The usual thinking in western forums has been that figures for the initial period after a komi adjustment may be a little unreliable as players try new strategies. To allow for that, we can look at figures for last year alone (i.e. 1 January 2007 to 21 December 2007): 4,014 games, Black 50.62%, White 49.38%. Figures for 1998 ~ 2003 at 5.5 komi were: 10,054 games. Black 52.4%, White 47.6%. In all periods, a breakdown of the figures suggests that Black has even more of an advantage in the later reaches of tournaments, i.e. the strongest players know how to use first mover better. In 2007's title matches the score was 23-19 to Black. In the period 2002-2007, Black won 51.34% of games at the final 9-dan dominated knockout level and 51.58% of games where the final stage was a league.

John Fairbairn wrote:Quoting from the GoGoD "History of Komi":

In September 2005, the Nihon Ki-in carried out a survey of 1,042 completed games at the new 6.5 komi. It found that Black had won 50.51% and White 49.49%. This was the nearest to parity ever achieved. The equivalent figures in the Nihon Ki-in's last survey under 5.5 komi showed Black won 52.42%.

Figures from Japan in 2008 showed that the latest komi of 6.5 still leaves Black a slight edge. In 19,702 games from 6 November 2002 up to 31 December 2007, Black won 50.59% and White won 49.41%. The usual thinking in western forums has been that figures for the initial period after a komi adjustment may be a little unreliable as players try new strategies. To allow for that, we can look at figures for last year alone (i.e. 1 January 2007 to 21 December 2007): 4,014 games, Black 50.62%, White 49.38%. Figures for 1998 ~ 2003 at 5.5 komi were: 10,054 games. Black 52.4%, White 47.6%. In all periods, a breakdown of the figures suggests that Black has even more of an advantage in the later reaches of tournaments, i.e. the strongest players know how to use first mover better. In 2007's title matches the score was 23-19 to Black. In the period 2002-2007, Black won 51.34% of games at the final 9-dan dominated knockout level and 51.58% of games where the final stage was a league.

RobertJasiek wrote:to really find out the proper komi only by empirical means, also greater komi values must be tested (exclusively or by bidding).

magic wrote:Interesting to ready what you have written.

RobertJasiek wrote:to really find out the proper komi only by empirical means, also greater komi values must be tested (exclusively or by bidding).

That is why we should really store the score difference and the komi that was used for each played game, and not just who won. In that way it would be easy to calculate what the komi should have been in order to get the closest to a 50:50 ration between white's wins and black's wins, simply by calculating komi + black's score - white's score for each game and calculating the median of that. The median is then what komi really should be.

skydyr wrote:The problem is that stronger players modify their play based on the komi, so you can't extrapolate from one komi to another without taking that into account.

EDIT:
Also, when you can count well and know what the score will be, you can play more conservatively to preserve a lead, resulting in a win by a small number of points where more were possible, to keep from making mistakes.

magic wrote:

skydyr wrote:The problem is that stronger players modify their play based on the komi, so you can't extrapolate from one komi to another without taking that into account.

EDIT:
Also, when you can count well and know what the score will be, you can play more conservatively to preserve a lead, resulting in a win by a small number of points where more were possible, to keep from making mistakes.

Ah, I see. So a good player who has the upper hand would rather play defensive to maximize his chance of winning, even if that meant that he would maybe win by 2 or 3 points less in average than if he would played more offensive?

shapenaji wrote:If there were a large number of bangneki games available somewhere, that would be an interesting place to determine exact komi. Unfortunately, such things are never recorded.

Addendum:
Supposing that 7 is, in fact, the correct komi. Would it be worth allowing Jigo again to make the game fairer?

magic wrote:Okay, so it can really swing in both directions. Hard to know in which way the komi will affect the median score difference then? (not including komi)