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Subject: Re: Does this position blow up your program? 2

Author: Uri Blass

Date: 03:30:35 12/26/02

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On December 26, 2002 at 06:06:10, Sune Fischer wrote:

>On December 26, 2002 at 05:59:23, Uri Blass wrote:
>
>>On December 26, 2002 at 05:17:03, Sune Fischer wrote:
>>
>>>On December 25, 2002 at 23:23:48, Drexel,Michael wrote:
>>>
>>>>[D] Q2Q2Q1/1R6/3BR3/3k3N/2RB2Q1/5R2/Q2Q2Bp/3N3K w - - 0 1
>>>>
>>>>Problem:
>>>>White to move
>>>>If white gives check it has to be mate in one.
>>>>Find a legal position with the highest number of possible checks.
>>>>
>>>>I discovered this 5 years ago. Took me about 16 hours to find it.
>>>>I think it is possible to find a proof that it is not possible to find more:
>>>>
>>>>85 mates in one! :-)
>>>
>>>Are you sure, I "only" count 78 mates??
>>>
>>>Mates ply 0........: 0
>>>Mates ply 1........: 78
>>>Mates ply 2........: 0
>>>Mates ply 3........: 468
>>>Mates ply 4........: 0
>>>Mates ply 5........: 9538
>>>
>>>how did you count them?
>>>
>>>>I must have been crazy.
>>>
>>>Yes, you will fit right in here :)
>>>
>>>-S.
>>
>>
>>modified perft of movei agree with your numbers.
>>
>>It counts 1380065-10084 mates at ply 7 and 0 mates in ply 8
>>
>>Number of stalemates
>>52 at depth 1
>>781-52 at depth 3
>>12034-781 at depth 5
>>2095567-12034 at depth 7
>>
>>Can you check that these numbers are correct?
>
>I get:
>
>Ply  CheckMates	Stalemates
>0             0	         0
>1            78         52
>2             0          0
>3           468        729
>4             0          0
>5          9538      11253
>6             0          0
>7       1369981    2083533
>
>I'm running the ply 9 now, going to take a while so don't hold your breath ;)
>
>I wonder how long before black gets a mate, that pawn could promote and become
>dangerous!
>
>-S.

It needs 6 plies to promote but I guess that even 10 plies or 12 plies are not
enough for mate.

1.Qb1 Kxc4 2.Bh3 Kd5 3.Kg2 h1Q+ 4.Kg3 but even here I do not see a short mate
for black(no mate in 5 plies)

4...Qxf3+ is logical here and after this move white has 207 mate in 2 but black
has no mate in 2.
white has 370326 mates in 3 but black has no mate in 3 after white possible
replies that mean mate in 7 from the initial position.

Uri





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