On 05/08/2014 14:05, Erik van der Werf wrote:
On Tue, Aug 5, 2014 at 2:20 PM, Nick Wedd <[email protected]> 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...
The issue is not that it's difficult, it's that wms will not have time
to do it. If he ever does have some time to work on KGS, there are
many higher priorities, including getting the stone-click in the human
client to work without a messy bodge, and getting the authentication
for the human client to work for users who install the latest release
of Java.
Nick
--
Nick Wedd
[email protected]
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