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Subject: Re: Endgame position / running passed pawns

Author: blass uri

Date: 14:51:35 06/05/00

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On June 05, 2000 at 11:46:41, Robert Hyatt wrote:

>On June 05, 2000 at 10:31:32, blass uri wrote:
>
>>On June 05, 2000 at 09:09:51, Robert Hyatt wrote:
>>
>>>On June 05, 2000 at 08:22:44, Steffen Jakob wrote:
>>>
>>>>Hi!
>>>>
>>>>This is a position from an interesting standard game MissSilicon - Hossa, played
>>>>today at ICC:
>>>>
>>>>[D]5k2/7K/6P1/1p3p2/1P5P/1Pb5/8/8 w
>>>
>>>
>>>
>>>I think there are times where you have to depend on your search.  Normally
>>>this is won by black, because black has a bishop to stop white's pawns.  I
>>>suspect that if you try to write special-purpose code to catch this, it will
>>>end up being wrong more than it is right.
>>
>>I agree that writing a special code to catch this case and many other cases is
>>not trivial but I believe that it is not impossible.
>>
>>  This is a precise tempo-counting
>>>issue that just barely lets the 'loser' win.
>>>
>>>I'd likely just take the loss and run.  It takes Crafty 9 plies (0 seconds
>>>of course) to see that the bishop is not winning.  I don't see an obvious
>>>evaluation trick to make this show up faster...
>>
>>Hiarcs7.32 needs only 5 plies to see that white is winning because of
>>extensions.
>>
>>Uri
>
>
>That doesn't matter. How _long_ does Hiarcs need?  It doesn't matter whether
>you need 5 plies or 9 plies.  What matters is "how many seconds"???  Because it
>is easy to extend a lot and pick this up quicker (shallower plies) but take
>longer overall to find the problem.  Here is what I get, for reference:
>
>         nss  depth   time  score   variation (1)
>starting thread 1
>starting thread 2
>starting thread 3
>                1     0.00  -5.90   1. h5
>                1->   0.00  -5.90   1. h56
>                2     0.00     --   1. h5
>                2     0.00  -6.77   1. h5 Bxb4
>                2     0.00  -6.52   1. Kh6 f4
>                2->   0.01  -6.52   1. Kh6 f4
>                3     0.01  -6.22   1. Kh6 f4 2. h5
>                3     0.01     ++   1. h5!!
>                3     0.01  -5.40   1. h5 Bg7 2. h6
>                3->   0.01  -5.40   1. h5 Bg7 2. h6
>                4     0.02  -5.14   1. h5 f4 2. h6 Bxb4
>                4->   0.02  -5.14   1. h5 f4 2. h6 Bxb4
>                5     0.23     ++   1. h5!!
>                5     0.24  -3.95   1. h5 f4 2. h6 f3 3. g7+ Bxg7 4. hxg7+
>                5->   0.24  -3.95   1. h5 f4 2. h6 f3 3. g7+ Bxg7 4. hxg7+
>                6     0.25  -4.26   1. h5 Bg7 2. h6 Bxh6 3. Kxh6 f4
>                6->   0.26  -4.26   1. h5 Bg7 2. h6 Bxh6 3. Kxh6 f4
>                7     0.27  -4.26   1. h5 Bg7 2. h6 Bxh6 3. Kxh6 f4 4.
>                                    Kh7
>                7->   0.27  -4.26   1. h5 Bg7 2. h6 Bxh6 3. Kxh6 f4 4.
>                                    Kh7
>                8     0.28  -4.43   1. h5 Bg7 2. h6 Bxh6 3. Kxh6 f4 4.
>                                    g7+ Kg8 5. Kg5
>                8->   0.29  -4.43   1. h5 Bg7 2. h6 Bxh6 3. Kxh6 f4 4.
>                                    g7+ Kg8 5. Kg5
>                9     0.38     ++   1. h5!!
>                9     0.49   3.78   1. h5 Bg7 2. h6 Bxh6 3. Kxh6 Kg8 4.
>                                    Kg5 Kg7 5. Kxf5
>                9->   0.49   3.78   1. h5 Bg7 2. h6 Bxh6 3. Kxh6 Kg8 4.
>                                    Kg5 Kg7 5. Kxf5
>               10     0.50   3.68   1. h5 Bg7 2. h6 Bxh6 3. Kxh6 Kg8 4.
>                                    Kg5 f4 5. Kxf4 Kg7
>               10->   0.51   3.68   1. h5 Bg7 2. h6 Bxh6 3. Kxh6 Kg8 4.
>                                    Kg5 f4 5. Kxf4 Kg7
>               11     0.52   3.78   1. h5 Bg7 2. h6 Bxh6 3. Kxh6 Kg8 4.
>                                    Kg5 f4 5. Kxf4 Kg7 6. Kf5
>               11->   0.53   3.78   1. h5 Bg7 2. h6 Bxh6 3. Kxh6 Kg8 4.
>                                    Kg5 f4 5. Kxf4 Kg7 6. Kf5
>               12     0.55   3.88   1. h5 Bg7 2. h6 Bxh6 3. Kxh6 Kg8 4.
>                                    Kg5 f4 5. Kxf4 Kh8 6. Ke5 Kg7
>         (2)   12->   0.58   3.88   1. h5 Bg7 2. h6 Bxh6 3. Kxh6 Kg8 4.
>                                    Kg5 f4 5. Kxf4 Kh8 6. Ke5 Kg7
>               13     0.60   3.78   1. h5 Bg7 2. h6 Bxh6 3. Kxh6 Kg8 4.
>                                    Kg5 f4 5. Kxf4 Kh8 6. Ke5 Kg7 7. Kf5
>         (2)   13->   0.63   3.78   1. h5 Bg7 2. h6 Bxh6 3. Kxh6 Kg8 4.
>                                    Kg5 f4 5. Kxf4 Kh8 6. Ke5 Kg7 7. Kf5
>               14     0.66     ++   1. h5!!
>               14     6.49   4.19   1. h5 Bg7 2. h6 Bxh6 3. Kxh6 Kg8 4.
>                                    Kg5 f4 5. Kxf4 Kf8 6. Kg5 Ke7 7. g7
>                                    Kf7 8. Kh6
>               14->   6.56   4.19   1. h5 Bg7 2. h6 Bxh6 3. Kxh6 Kg8 4.
>                                    Kg5 f4 5. Kxf4 Kf8 6. Kg5 Ke7 7. g7
>                                    Kf7 8. Kh6
>
>
>Crafty finds the right move from depth=1.  After .38 seconds it realizes that
>white is winning.  I can crank up the passed pawn extension and see this
>quicker in terms of depth, but the time will probably be slower overall.  IE
>don't be mislead by 'shallow depth finding'.  I think depth doesn't matter at
>all.  It is _time_.

I do not know the exact time but it needs clearly less than 1 second on p200MMX
to see evaluation of +4.88

Uri



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