On Tue, Aug 5, 2014 at 2:20 PM, Nick Wedd <n...@maproom.co.uk> wrote: > On 05/08/2014 12:25, Erik van der Werf wrote: >> >> Here's an intuitive argument for why I believe 7.5 komi is too high on >> any of the larger boards. >> >> On very small (square odd-surface) boards there is no room for White >> to live (Black takes all points). Past a certain point (5x5), Black >> can no longer control the full board, so White also starts to take >> some points. Initially there is not much room left for White, so the >> perfect komi remains a bit high (e.g., 9 for 7x7), but as the size >> increases the White move values start to approach those of Black and I >> expect the advantage of the initiative to decrease to a constant >> (probably 7 or 5 points). >> >> Since we have reasonable indications that the first player score on >> 9x9 is no higher than 7, and because it is unlikely to increase with >> size, the main question is if it remains at 7, or if it drops down >> further (e.g., to 5). (even values such as 6 are much less likely on >> odd-surface boards with area scoring). >> >> Of course one could still argue that 7 is correct, and we just add 0.5 >> to prevent ties, but then I'd rather subtract 0.5 and go for a komi >> of 6.5 because I prefer the small advantage to go to the first player. > > > > I find your logic convincing. We'll see if others do. > > But even if they do, is that a sufficient reason for changing the komi > in events that I run? > > With 9x9, getting the komi slightly wrong biases the results markedly, > and so should be avoided. With 19x19, getting the komi slightly wrong > makes much less difference to the results of games, and it may be better to > use slightly wrong komi than to inconvenience those bot > authors who have not persuaded their bots to understand integer komi > and the possibility of jigo.
Sure, I understand. But on the other hand, does it really matter if occasionally some bot doesn't get jigo? Also, they have to get this right anyway for the 9x9 tournaments. I think the choice should be made based on weighting the advantage of having no ties (always a winner, easy pairing) against the amount of bias in the starting condition (so it also matters if, e.g., you run single or double round robin). Weighting the two, I prefer fractional komi for 19x19 and integer komi for 9x9. For 13x13 I'm not sure, but I'm tempted to go for integer komi as well. In any case, if you don't want integer komi you could still switch to 6.5. It might be interesting to see if that turns it into hinting at a slight advantage for Black. >> BTW Nick, is there any chance that you will at some point run a kgs >> tournament with territory scoring? I'm still hoping that one day we >> will play Japanese rules with 6.5 komi. (Regardless of the komi, I >> think the more fine-grained territory scores would make the games more >> interesting, especially on 9x9.) > > > I use area scoring because, with the KGS clean-up procedure, it allows > almost all games to end without my intervention. KGS does not offer a > similar mechanism for what it calls "Japanese rules". I do not want > to be required to apply my rules knowledge and counting ability in a > game which ends with the players disputing the status of a "bent four > in the corner". Ah yes, that makes sense. Implementing a proper cleanup procedure for territory scoring is not difficult. Of course a practical implementation might differ slightly from the official Japanese rules, but then again KGS didn't really implement the official Chinese rules either... Erik _______________________________________________ Computer-go mailing list Computer-go@dvandva.org http://dvandva.org/cgi-bin/mailman/listinfo/computer-go
