[Computer-go] God Go Rank

Don Dailey dailey.don at gmail.com
Tue Oct 12 07:45:34 PDT 2010


On Tue, Oct 12, 2010 at 10:36 AM, terry mcintyre <terrymcintyre at yahoo.com>wrote:

> Uh, are you allowing for the possibility that both black and white play
> imperfectly?
>

Yes,  Brian commented on that.   In fact I think that lends strength to his
conclusion that masters.




>
> Terry McIntyre <terrymcintyre at yahoo.com>
>
> Unix/Linux Systems Administration
> Taking time to do it right saves having to do it twice.
>
>
> ------------------------------
> *From:* Brian Sheppard <sheppardco at aol.com>
> *To:* computer-go at dvandva.org
> *Sent:* Tue, October 12, 2010 10:04:31 AM
> *Subject:* [Computer-go] God Go Rank
>
>  (Was 19x19 gets interesting.)
>
>
>
> Mark Boon commented that he believes that top pros make "a few dozen"
> errors
>
> per game. I concur, and I think that we can construct a model of Go
>
> competitions that supports that belief.
>
>
>
> with a 6.5 komi, the game is probably a forced win for Black. (It could be
>
> White, or even a draw by repetition, but that doesn't affect what follows.)
>
> So a perfect player would win 100% as Black, and also win as White unless
>
> his opponent plays perfectly.
>
>
>
> When top-ranked pros play head-to-head (e.g., in title matches) what we
>
> observe is closer to 53% wins for Black.
>
>
>
> Imagine an opponent that made an error on 1% of his turns. His probability
>
> of playing a complete game (say 130 moves) without an error is around 27%.
>
> It should be clear that such a player would win a lot more than 53% as
> Black.
>
>
>
> Maybe it isn't so clear. We are counting errors in point differential, so
>
> Black would win if he plays perfectly or if White makes errors that
> balance.
>
> If White had the same error rate as Black, then Black would win roughly
> 63%.
>
>
>
> So top pro error rates must exceed 1%.
>
>
>
> If the error rate were 2% then Black would still win much too often.
>
>
>
> I believe that top pros must have error rates around 9% in order to have a
>
> 53% win rate for Black. That implies a dozen errors per game per player.
>
>
>
> I am not sure what this means for dan ranking. But if 1 stone = 6 points,
>
> and 1 error = 2 points, then perfect players are about 4 stones better
>
> than top human pros.
>
>
>
> Here, "top" doesn't mean 9p; "top" means title holders.
>
>
>
> Brian
>
>
>
>
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