Komi on smaller boards

[HermanHiddema]

In 19x19, lots and lots of pro play confirms 7 to be about right.

Why? Isn't Black still winning significantly more than 50%? So the komi must be 6.5 or greater!

Since when is 7 no longer greater than 6.5?

Current statistics for professional play with 6.5 komi show a winning percentage of about 50.5%. Previously, at 5.5 komi, this was around 53%.

[RobertJasiek]

Current statistics for professional play with 6.5 komi show a winning percentage of about 50.5%.

In which countries? I think in China and Taiwan with 7.5 komi (equivalent) they also have Black above 50%. Until dynamic komi and / or komi bidding are used, pro game statistics will remain too partial because playing style adapts to a given komi.

[HermanHiddema]

Current statistics for professional play with 6.5 komi show a winning percentage of about 50.5%.

In which countries?

Given that I'm speaking of professional play at 6.5 komi, I think it is pretty obvious I'm talking about Japan and Korea.

I think in China and Taiwan with 7.5 komi (equivalent) they also have Black above 50%.

In fact, according to SL's http://senseis.xmp.net/?Komi/Statistics, area scoring with a komi of 7.5 or 8 (Ing rules, so effectively 7.5) show a winning percentage of about 50.5% for White.

If anyone has statistics over a larger sample size, please post them.

Until dynamic komi and / or komi bidding are used, pro game statistics will remain too partial because playing style adapts to a given komi.

At the moment, it is the best method we have, and the statistcis strongly hint that 7 komi is correct. We would only really have absolute certainty on the issue if we find perfect play, which we can pretty much rule out.

[RobertJasiek]

the statistcis strongly hint that 7 komi is correct

Rather they show that too few games are measured.

[Bill Spight]

the statistcis strongly hint that 7 komi is correct

Rather they show that too few games are measured.

I wouldn't say that. Statistics on games in Japan back when komi was 4.5 indicated a median board score of 7. Ing based his komi of 7.5 on statistics many years ago. Many, many, many games have been used for komi statistics.

It is possible that, as pro play improves, komi will change. But the games which would indicate that have yet to be played.

[HermanHiddema]

the statistcis strongly hint that 7 komi is correct

Rather they show that too few games are measured.

Have you ever heard of a thing called "math"? Maybe you should read up on it some time before spouting nonsense.

[RobertJasiek]

Statistics on games in Japan back when komi was 4.5 indicated a median board score of 7. Ing based his komi of 7.5 on statistics many years ago. Many, many, many games have been used for komi statistics.

All fine and well but my comment has referred to SL's statistics with just a few hundred games.

[RobertJasiek]

Maybe you should read up on it some time before spouting nonsense.

Calling 410 games for 7.5 komi sufficient is the nonsense. Besides the bound 8p+ is arbitrary.

[Magicwand]

If we take theoretical komi to be the summed-up value of the influence around a stone, then komi is the value of the largest first move on the board.

As I am about to show for 19x19 in Joseki / Volume 2 / Strategy, the value of the first stone's sum of territory and territorial value of influence is about 8.8 points. Details will be in the book.

So you are claiming that komi we are using is incorrect and you will prove that?
How arogant....

[HermanHiddema]

Maybe you should read up on it some time before spouting nonsense.

Calling 410 games for 7.5 komi sufficient is the nonsense. Besides the bound 8p+ is arbitrary.

I never said it was sufficient, in fact I specifically asked in my post if anyone had a larger sample size. Still, the available evidence does hint at a correct value of 7. Without evidence to the contrary, that is the best current guess we can make.

You standard of evidence, so far, has been "I've heard that". That right up there with "my mother always said" and "I have a gut feeling".

[Li Kao]

Can you please state if you're talking about area or territory scoring? The correct area scoring komi might be larger than the correct territory scoring komi.

And how do you even define correct? Correct for perfect play? Correct for strong professional level? The komi for 50% winrate might depend on player strength and style. Komi bidding on the other hand circumvents these problems.

If we take theoretical komi to be the summed-up value of the influence around a stone, then komi is the value of the largest first move on the board.

As I am about to show for 19x19 in Joseki / Volume 2 / Strategy, the value of the first stone's sum of territory and territorial value of influence is about 8.8 points. Details will be in the book.

Doesn't this imply a komi of around 4.5? Isn't the value of the first move about twice the komi? But you stated the komi should be at least 6.5. Doesn't sound consistent to me.

In the limit of infinitely many moves where the value of moves decreases slowly and steadily the komi is exactly half the value of the first move. But of course that disregards cases with sudden drops in temperature and parity related effects. But I think it should still be around half the move value.

[RobertJasiek]

So you are claiming that komi we are using is incorrect and you will prove that?

I will give a pretty convincing reasoning but not a proof.

[RobertJasiek]

has been "I've heard that"

International Go Rules Forum. Japanese and Chinese were bringing komi statistics, each supporting their preferred komi 6.5 or 7.5 and each, IIRC, based on many pro games. The texts were in Asian languages so I cannot become more precise than "I have heard.". Problem with the statistics was: Included not very many recent games since last komi changes but I think still in the few thousands rather than the few hundreds.

Ing is also said to have done statistics but I have never seen them. So, sorry, only "I have heard.". It is not random input though. Maybe someone can track down those pro game statistics.

[RobertJasiek]

Can you please state if you're talking about area or territory scoring?

In theory this is important, of course. In practice, as long as area scoring uses Standard Area Komi like 7.5, almost all games have the seki parity even and the same winner as under territory scoring. Therefore the statistics are comparable.

And how do you even define correct? Correct for perfect play?

Ideally yes.

Isn't the value of the first move about twice the komi?

It depends whether the value of a move is considered with miai counting or deire counting. I use miai counting.

But you stated the komi should be at least 6.5. Doesn't sound consistent to me.

That remark was made in a different context. Read both independently from each other.

[RobertJasiek]

the value of the first stone's sum of territory and territorial value of influence is about 8.8 points.

Correction. I made a simple counting mistake. It is only 7.9 ~ 8.0 points. The estimate is a sort of lower bound though.

7.0 would definitely be too small. It would be like saying: "With a shimari (2 stones), you make 11 points of territory but its influence is worth only 3 points."