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Subject: Re: do all programs see this draw here....

Author: Christophe Theron

Date: 09:05:10 12/28/03

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On December 28, 2003 at 10:48:55, Robert Hyatt wrote:

>On December 27, 2003 at 17:47:08, Christophe Theron wrote:
>
>>On December 27, 2003 at 09:32:46, Sune Fischer wrote:
>>
>>>On December 27, 2003 at 00:51:11, Mike Byrne wrote:
>>>
>>>>
>>>>[d]8/r7/8/5bk1/8/5B2/5RPP/6K1 b - - 0 1
>>>>Crafty19.08 SE  UCI 2 MB:
>>>
>>>Just 2 MB? :)
>>>
>>>> 7   00:00  0.01   1. ... Ra1+ 2.Rf1 Rxf1+ 3.Kxf1 Bh3 4.gxh3
>>>> 8   00:00  0.01   1. ... Ra1+ 2.Rf1 Rxf1+ 3.Kxf1 Bh3 4.gxh3
>>>> 9   00:00  0.01   1. ... Ra1+ 2.Rf1 Rxf1+ 3.Kxf1 Bh3 4.gxh3
>>>>10   00:00  0.01   1. ... Ra1+ 2.Rf1 Rxf1+ 3.Kxf1 Bh3 4.gxh3
>>>>11   00:00  0.01   1. ... Ra1+ 2.Rf1 Rxf1+ 3.Kxf1 Bh3 4.gxh3
>>>>12   00:00  0.01   1. ... Ra1+ 2.Rf1 Rxf1+ 3.Kxf1 Bh3 4.gxh3
>>>>13   00:01  0.01   1. ... Ra1+ 2.Rf1 Rxf1+ 3.Kxf1 Bh3 4.gxh3
>>>>14   00:04  0.01   1. ... Ra1+ 2.Rf1 Rxf1+ 3.Kxf1 Bh3 4.gxh3
>>>>15   00:06  0.01   1. ... Ra1+ 2.Rf1 Rxf1+ 3.Kxf1 Bh3 4.gxh3
>>>
>>>
>>>I do not understand how everybody can solve that so fast..:(
>>>
>>>frenzee needs almost 17 seconds.
>>>
>>>10 242 620 4841759 1...Ra1+
>>>10 235 723 5652670 1...Ra1+ 3.Rf1 Ra3 4.g3 Rb3 5.h4+ Kg6 6.Rf2 Kf6 7.Be4 Rxg3+
>>>11 236 1043 8219719 1...Ra1+ 3.Rf1 Ra3 4.g3 Bh3 5.Bg2 Bf5 6.Re1 Ra2 7.Re7 Kf6 12
>>>0 1690 13513082 1...Ra1+ 3.Rf1 Rxf1+ 4.Kxf1 Bh3 5.gxh3 Kf6 6.Kf2 Kg7 7.Bd5 13 0
>>>1706 13682948 1...Ra1+ 3.Rf1 Rxf1+ 4.Kxf1 Bh3 5.gxh3 Kf6 6.Kf2 Kg7 7.Bd5
>>>
>>>-S.
>>
>>
>>
>>By evaluation. After Ra1+ Rf1 Rxf1+ Kxf1 Bh3 gxh3 the position is a theorical
>>draw because you only have pawns on the H file, the Bishop is not of the color
>>of the promotion square and the opponent's King is already too close from this
>>promotion square.
>>
>>Adding this evaluation rule will not make your program stronger, but you will be
>>proud to answer to this kind of message "yes, my program solves it in
>>0:00:00.00s". :)
>>
>>
>>
>>    Christophe
>
>
>Actually this _will_ make your engine stronger.  In 1981 we played a game vs
>USCF master Joe Sentef and this came up.  We were winning and he offered a free
>piece which would have left us in exactly such a drawn position.  Fortunately
>we knew about this back in 1981 and we did not take the piece and won the game
>handily...
>
>I've seen it happen multiple times on ICC.  Not frequently, but frequently
>enough that it makes a difference.



Oops... I have hit "Submit" before writing anything! :)

Yes you are right. Actually I thought that in order to solve this problem you
should know not only about KKBP but also about KKBPP with both pawns on the H
file.

But in this particular case it appears you only need to know about KKBP.

Adding knowledge about KKBPP certainly improves a program, but very little in
practice, that's what I meant. Of course it's always nice to have it...



    Christophe



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