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Subject: Re: If you like to find a mate...

Author: leonid

Date: 19:21:05 01/18/01

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On January 18, 2001 at 22:06:37, leonid wrote:

>On January 18, 2001 at 19:13:22, Paul wrote:
>
>>On January 18, 2001 at 19:01:08, Pete Galati wrote:
>>
>>>On January 18, 2001 at 18:44:05, leonid wrote:
>>>
>>>>Hi!
>>>>
>>>>If you would like to find a mate here is one position. It is very easy to solve
>>>>but not that simple to find shortest mate.
>>>>
>>>>I failed here even in 3 hours to find shortest mate through brute force search.
>>>>Maybe you will have better chance.
>>>>
>>>> 1k4q1/1pppPr2/PbbP1N1n/QP2rn1R/1q6/1q2RBB1/q1q2PPP/6NK black to go
>>>>
>>>>Leonid.
>>>
>>>Is this the right position?
>>>
>>>[D]1k4q1/1pppPr2/PbbP1N1n/QP2rn1R/1q6/1q2RBB1/q1q2PPP/6NK b - - 0 1
>>
>>If so, then mine says it's a mate in 10 for black starting with Nxg3+ ...
>>It looks like a daily reverse auction ... Anyone lower, anyone? :)
>>
>>Paul
>
>Position is exact and response 10 moves must be or shortest possible, or very
>close move. Actually my program solved this position through selective search in
>11 moves. Solution was instant. Finding shortest mate is the other story.
>Through brute force program said in 8 mate is not there. Only 9 still could be
>looked.


Mistake! My program solved this position not by 11 moves selective search but by
10. Found this when I went to program and solved this position once again. My
mistake came probably from the fact that I created today around 5 or 6 different
positions. Few of them were solved by 12 and 11 moves. Only one, that I liked
the most, I put here.

Leonid.

>I found that branching factor was terrible to see 9 moves. AMD 400Mhz.
>
>8 moves - 2h 44 min.
>7 moves - 2 min 48 sec.
>6 moves - 7 sec.
>
>Leonid.



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