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Subject: Re: If you like to solve easy mate...

Author: Heiner Marxen

Date: 15:27:16 02/22/01

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On February 22, 2001 at 17:04:16, leonid wrote:

>On February 22, 2001 at 16:37:31, leonid wrote:
>
>>On February 22, 2001 at 09:51:57, Ricardo Gibert wrote:
>>
>>>On February 22, 2001 at 08:03:25, leonid wrote:
>>>
>>>>Hi!
>>>>
>>>>If you like to solve one very easy mate then this is right position:
>>>>
>>>>[D]1b2nQrk/2Q3qn/1q1q2Q1/1Q1N1nq1/b1qQqN1q/1BB1qQ2/1qQ4Q/3K4 w - -
>>>>
>>>>Please indicate your result.
>>>>
>>>>Thanks,
>>>>Leonid.
>>>
>>>Compose one similar to this that ends in a forced stalemate after a dozen moves,
>>>then I will really be impressed!
>>
>>Maybe you will be impressed but then it will be difficult for computer to solve
>>new position by brute force. This position is very short one and can be easely
>>solved by brute force. Reason - branching factor (even if position is impressive
>>with 9 queens) is very moderate. Good position is the position that contain some
>>need for search but where solution is not that far.
>>
>>Leonid.
>
>After this message, I went to my position to find it what time it could be
>solved by brute force. On AMD 400Mhz computer it was:
>
>4 moves - 0.6 sec - no solution
>5 moves - 3.8 sec - no solution
>6 moves - 25 sec  - no solution
>7 moves - 3.8 sec - solution found
>
>Selective search take this position in 0.055 sec.
>
>Now you can see why I have said that position is easy. Try to solve it with
>every solid program (like Chess Master or Heiner's solver) and you will see that
>I was right.
>
>Many pieces on the board are very often to give some animation to it but not
>necessarily to make position complex.
>
>Leonid.

Are you sure the position is correct?  Chest gives a mate in 4:

 Qxg8+ Kxg8 Qbxe8+ =*= Qdxg7+ Nxg7 Qcxg7#

As far as I can see that is correct.
(0.21 secs, K7/600)

Heiner



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