Life In 19x19

RBerenguel wrote:OGS and white, I have asked for this to be fixed on the 9x9 (and hopefully all other) ladder games, at least.

If there are a lot of 9x9-tourney and ladder games of shin-OGS in your database, than this bias makes a lot invalid: The stronger player is always white, so you'd expect white to win more often (with fair komi). I've seen people complaining about the high 9x9-komi in the chat. If they were always taking white against stronger players, they would complain that 6.5 points is never enough, I'm sure.

I don't know why the devs of shin-OGS had the idea to do that in tournament games and still stick to it. In ladder games it is kind of debatable whether the defender (not the stronger player) always has white. In the tournaments it doesn't make sense to me at all.

illluck wrote:I think you are overthinking it, RBerenguel. Including resignations is the simplest way to ensure there are no biases. Early resigns should cancel out, and there is no need to count the score - it's not meaningful for games that are scored either.

The way I understand the setting, rberenguel took for the amateur games only 6.5-komi games and checked how many swings in results you get if you assumed that the komi were lower. So you have to get rid of resignations.

Probably guilty of overthinking (wouldn't be the first time). okay, ran again without filtering resignations (in the AWK file just remove the regexp at the beginning of the main clause)

Amateur games: Pro games with 6.5 komi: Was tempted to check 5.5 komi games (which are roughly 50% of the games I have) but it would mean rewriting how I test for changes in score and I'm a little too busy now to do it, maybe later.

Re: Bayu and swings: Indeed, this was the way I thought it. And yes, OGS games are rigged like this with the stronger player always getting white, so it is to be expected that he wins more often. I have asked to randomise nigiri in ladder games: if games are no handicap, why should they be always stronger player has white? I'd prefer full nigiri for the ladder. I think it makes more sense specially in 9x9, because even if the komi is large enough or small enough, the way you approach the game as B or as W are very different, and being on top of the ladder should account for both.

Being the highest ranked (ex)player on OGS I would dislike never being able to play a black fuseki!

You can't try to adjust komi after the game - players will play differently with different komi, especially on 9x9 when it's so easy to count.

HermanHiddema wrote:currently OGS always gives the stronger player white

Wow, that's seriously braindead and entirely defeats the purpose of giving white komi.
I hope it's a bug and not a feature.

illluck wrote:You can't try to adjust komi after the game - players will play differently with different komi

I'm amazed this needed to be pointed out.

I regularly sacrifice a few points in 9x9 endgames to simplify the game.

leichtloeslich wrote:

HermanHiddema wrote:currently OGS always gives the stronger player white

Wow, that's seriously braindead and entirely defeats the purpose of giving white komi.
I hope it's a bug and not a feature.

It is more a feature than a bug. If I remember correctly, it doesn't apply when you challenge somebody. So it affects "only" ladders and tournaments.

leichtloeslich wrote:

illluck wrote:You can't try to adjust komi after the game - players will play differently with different komi

I'm amazed this needed to be pointed out.

I regularly sacrifice a few points in 9x9 endgames to simplify the game.

I principally agree with you, but if it is just 1 point you might get away with it concerning the amateur games. I don't think you make a 1.5-win deliberately into a 0.5-win because it simplifies the game. And given the data that is there, it's at least something possibly interesting you can look at. I'm no coder, so I'm happy if other people do this kind of things. And I'm even happier when they explain what they do. I simply reserve the right to interpret the results cautiously, if at all.

My understanding is the higher rated player always being white is a bug.

I think the analysis is unfortunatedly too affected by players' ability to count. I think if the winrate is around 50% at 6.5 komi then it's a decent enough indication of it being approximately the right amount at this time. My personal experience is that 6.5 is not too far from being correct.

I wonder, then, why komi (except on ☯GS and DGS) still sticks with the 0.5 instead of using anywhere between 0.1 and 0.9 (plus whatever may be needed to “guarantee” evenness).

bayu wrote: I principally agree with you, but if it is just 1 point you might get away with it concerning the amateur games. I don't think you make a 1.5-win deliberately into a 0.5-win because it simplifies the game.

I have most definitely read 9x9 games to the end following the simple variation, determined I was ahead or behind by 0.5 points, and made my moves based on that. I can even think of a very particular 13x13 tournament game where I read that I would lose by 0.5 points following simple variations in the endgame and had to change up my play to increase my chances of winning, even if in the worst case it cost me more points. It's really not that hard for an amateur dan to do.

Dusk Eagle wrote:

bayu wrote: I principally agree with you, but if it is just 1 point you might get away with it concerning the amateur games. I don't think you make a 1.5-win deliberately into a 0.5-win because it simplifies the game.

I have most definitely read 9x9 games to the end following the simple variation, determined I was ahead or behind by 0.5 points, and made my moves based on that. I can even think of a very particular 13x13 tournament game where I read that I would lose by 0.5 points following simple variations in the endgame and had to change up my play to increase my chances of winning, even if in the worst case it cost me more points. It's really not that hard for an amateur dan to do.

Not even dan, I regularly try to squeeze some extra points in 9x9 to win if I see a close defeat ahead

19x19: Both theoretical studies by me, Bill Spight and others, and professional playing experience suggest 7 +- 0.5 komi. A final proof might be missing ALA the game is unsolved.

13x13: The most meaningful available evidence for 8.5 komi is the greatest likelihood of even-matched 0.5 score games in European 13x13 Championships, as I have observed and experienced 1993 - 2013. The value is greater than for 19x19 because 13x13 also is a lot about killing, and having the first move plays a great role for that.

9x9: Japanese professionals have used 6.5 komi for a longer time than for 19x19.

RobertJasiek wrote:19x19: Both theoretical studies by me, Bill Spight and others, and professional playing experience suggest 7 +- 0.5 komi. A final proof might be missing ALA the game is unsolved.

13x13: The most meaningful available evidence for 8.5 komi is the greatest likelihood of even-matched 0.5 score games in European 13x13 Championships, as I have observed and experienced 1993 - 2013. The value is greater than for 19x19 because 13x13 also is a lot about killing, and having the first move plays a great role for that.

9x9: Japanese professionals have used 6.5 komi for a longer time than for 19x19.

I'd have never thought possible you'd justify something based on what (Japanese) professionals do

I prefer best possible justifications, and currently I am not aware of any better justification for 9x9 komi.

Between newer players, i.e. players who don't really understand what they are doing yet, komi seems quite large and appears to give the advantage to white. It would seem to me that only between skilled players would moving first give that big of an advantage.

RobertJasiek wrote:A final proof might be missing ALA the game is unsolved.

This. Imagine a scathing line by black that forces the komi to be 8, or 10! Maybe we just haven't found it yet.