[Computer-go] Congratulations to Zen!

steve uurtamo uurtamo at gmail.com
Tue Apr 5 06:09:15 PDT 2011


thanks for the wealth of information. it's great to see raw data like this,

s.

On Tue, Apr 5, 2011 at 8:57 AM,  <valkyria at phmp.se> wrote:
> Quoting Jean-loup Gailly <jloup at gailly.net>:
>
>> Magnus writes:
>>
>>> Further, I would imagine many jigos could be quite peaceful short games
>>
>> What makes you think that optimal play should be peaceful? I speculate
>> that it should often be very complex, full of kos and tenukis, and
>> very difficult to understand for humans ("I play here because it gains
>> 1 point 20 moves later"). Some games might be peaceful, but a perfect
>> player can select arbitrarily complex sequences as long as they still
>> achieve the perfect result. There are a lot more complex games than
>> peaceful games.
>
> I think you are right. Maybe it is possible to create a book that leads to
> short jigos within the tree of "perfect games" but of course a strong book
> should prefer longer and complicated lines without making mistakes.
>
> My speculation was that short lines for jigo might be missing in a book for
> 7.5, but I do not think that can explain that lack of jigos in the
> tournament.
>
> I started a proper selfplay experiment with komi 7.0 with thinking time
> clearly longer than for CGOS to get high quality games.
>
> So far for 38 games there were 7 Jigo (18%).
> B won 11 28%
> W won 20 52%
>
> This seems to be the same patterns as in the tournament, where white has a
> clear advantage but less so because more jigo thanks to selfplay + much
> longer thinking times.
>
> Actually the games were played with following first moves forced
> systematically, as if a 1 ply uniform opening book
>
> Move #B Won/#Games
>
> E5 4/8
> E4 1/6
> F4 3/6
> E3 3/6 Jigo 1
> F3 0/6 Jigo 5
> G3 0/6 jigo 1
>
> Moves near the center are stronger as expected, but all jigos occurred with
> starting moves close to the edge.
>
> I know nothing can be concluded from this data set. But it is fun to
> speculate.
> Maybe E5 is a losing move for black! But it is such a complicated move and
> leads to fighting that Jigo are rare and a move such is F3 gives Jigo with
> perfect play.
>
> Speaking against this may be that with komi 5.5 the moves near the edge does
> not seems so strong for black. But so far I cannot rule out that all those
> opening moves are a win for black with komi 5.5. Anyway the opening in 9x9
> remains mysterious in most parts, no matter how much data I collect....
>
> Or is that with slow starting moves blacks only hope is jigo and thus
> achieves it more often?
>
>
> I used to be skeptical against integral komi but now I feel that it makes
> blacks play more interesting than it is with komi 7.5.
>
> I wonder if Don would be willing to start a CGOS server with 9x9 komi 7.0?
> And would people then be willing to play on it? I think in the long term
> this is the best way getting an idea how Jigo impacts on play. It might even
> help books development for 7.5 because black lines that loses with no chance
> of jigo might then be rejected, and the remaining lines is perhaps also
> strong for 7.5. (Speculation).
>
> I also checked game length for the jigos picking the last move that took a
> real point:
>
> 70 53 60 71 77 52 73
> Mean 65
>
> All other games were resigned on 20% win rate (in prefer many games in self
> play, compared to be sure that the right player wins), and were on average
> much shorter.
>
> Resigned games
> 75 35 38 53 58 45 46 51 22 44 38 44 54
>
> Mean 46
>
> So it seems to be no evidence for any "quick" Jigos for this preliminary
> result.
>
> Magnus
>
>
>
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