I think I remember seeing that at 5.5 komi, the winrate for Black was ~51%, and at 6.5, it's ~49? I don't remember where I saw these numbers, though.

I wonder how accurate the statistics are for komi. Are there enough games in the pros to discriminate between a 6.5 9dan and 5.5 9dan pro, or is increments of +-6.5 as much statistical power as they can get.

Professional Rankings don't work like amateur ones. First, they measure accomplishment rather than skill: You can have very strong 2-dan who haven't had enough time to climb the ranks further yet, and 9-dan who are no longer playing at their peak ability.

Secondly, they don't use the 1 rank=1 stone handicap rule amateurs do. A professional rank is only worth a fraction of a stone. So the difference between two ranks is already just a question of a couple points of komi.

depended on how much time given percentage differ.
for games 3 hours + white wins more game
for 1hour - black seem to win more.


it also depended on how strong you are and style you prefer.
amatures prefer black when komi is 6.5
strong pros prefer white when komi is 6.5

strong pros prefer white when komi is 6.5

and 15 of those 80 were wins (for both black and white fairly equally) by more than 7 points even after komi - that is, wins in which komi didn't matter anyway.

Why don't you go do the statistics yourself?

A while back, I looked at the first 400 games on gokifu.com. Over 300 of them were resigned before scoring, with only about 80 making it through to scoring, and 15 of those 80 were wins (for both black and white fairly equally) by more than 7 points even after komi - that is, wins in which komi didn't matter anyway. Absurd results like B+20 and W+30 were rare, but happened. I then took the average score difference, and compared the black/white win ratio, and got pretty much exactly what you'd expect if komi was correct, but it was such a small sample size with such varied results that I can't convincingly say it wasn't an accident.

All I am saying is that it disagree with just dismissing these two cases in your calculations as you apparently did.

First, komi (at least in Japan) was not historically decided by statistics. Modern komi started out at 4.5 points. Then for several years some events used 4.5 komi, while some used 5.5 komi. By the mid-1970s the shift was complete to 5.5 komi, AFAIK. In 76 or 77 Terry Benson asked me to review an article for the AGA Journal before publication, which claimed that the correct komi was 7. (At that time I had already predicted that Japanese komi would be 6.5 by the year 2000. Oops!) I made the comment that, while the stats suggested that 5.5 komi was too small, the current attitude was that Black had to be enterprising to overcome komi. A change in attitude to the effect that White is the one who needs to be enterprising, even with komi, might make a difference in the stats.

Terry sent me the data upon which the article was based, the results of 1400 pro games at 5.5 komi and 1400 pro games at 4.5 komi. To my surprise, the stats for the 4.5 komi games suggested a komi of 6.5. That being the case, it is surprising that the 4.5 komi lasted as long as it did.

Resignations don't mean komi wasn't relevant.

i am curious..does chess have advantage playing first?

i am curious..does chess have advantage playing first?