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Subject: Re: Mate in about 10... no, not mate in 9!

Author: Heiner Marxen

Date: 10:16:33 05/15/04

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On May 15, 2004 at 13:09:01, F. Huber wrote:

>On May 15, 2004 at 12:35:31, F. Huber wrote:
>
>>On May 15, 2004 at 11:34:04, Heiner Marxen wrote:
>>>
>>>According to Chest this actually is a mate in 9:
>>>
>>>PV: Qc7 Bf6 Rxe7+ Bxe7 Re3 Qf1+ Kxf1 Re6 Qc8+ Bd8 Rxe6+ fxe6 Qd7+ Kf8 Nxe6+ Kg8
>>>Qg7#
>>>
>>>I didn't ask for a solution tree, but the "refutation table" shows:
>>>refu 43: Qc7     Bf6     [   7-]
>>>solu          1: Bxd4+   [   6+]
>>>solu          2: Qf1+    [   6+]
>>>solu          3: Bh6     [   1+]
>>>solu          4: Re6     [   1+]
>>>solu          5: Rg6     [   1+]
>>>solu          6: Qc4     [   1+]
>>>solu          7: Qxc5    [   1+]
>>>solu          8: h4      [   1+]
>>>solu          9: Rg8     [   1+]
>>>solu         10: Rf8     [   1+]
>>>solu         11: Rh7     [   1+]
>>>solu         12: Rhh6    [   1+]
>>>solu         13: Rf6     [   1+]
>>>solu         14: Rdh6    [   1+]
>>>solu         15: f6      [   1+]
>>>solu         16: e6      [   6+]
>>>solu         17: e5      [   6+]
>>>solu         18: b6      [   1+]
>>>solu         19: Bf6     [   8+]
>>>solu         20: Bf8     [   4+]
>>>solu         21: Kf8     [   2+]
>>>solu         22: Be5     [   6+]
>>>solu         23: Rd7     [   2+]
>>>solu         24: Rd8     [   1+]
>>>solu         25: Qb6     [   1+]
>>>solu         26: Qe2     [   6+]
>>>solu         27: Qd3     [   1+]
>>>solu         28: Qa6     [   1+]
>>>solu         29: Qa5     [   1+]
>>>solu         30: Qxb4    [   1+]
>>>solu         31: Qa4     [   1+]
>>>So, Bf6 appears to be the best answer, all other moves result in shorter mates.
>>>
>>>Since it starts with a quiet move, it is hard to find, of course.
>>>[Chest needed 1 hour with 100MB hash on an Athlon 1500+]
>>>
>>>Cheers,
>>>Heiner
>>
>>Hello Heiner,
>>
>>what I´m missing in your refutation list is the black castling!?
>>(after 1.Qc7 black has actually 32 moves)
>>
>>Maybe you forgot the castling right when copying the FEN string (?),
>>this was the FEN in the original posting:
>>
>>4k2r/1p2ppb1/2pr4/QqNp1P1p/1P1P4/2P2R2/P5PP/4R1K1 w k - 0 1
>>
>>Eventually exactly this 1... 0-0 would be the only defence against 1.Qc7 -
>>Chest is just calculating on this position on my faster desktop, and I´m
>>really curious about the result ...
>>
>>Best regards,
>>Franz.
>
>Yes, exactly this black castling was the _key_ move -
>here is Chest´s result:
>
>ChestUCI Ver.3.5  UCI1:
>
>CPU: Pentium-4 2.66GHz
>FEN: 4k2r/1p2ppb1/2pr4/QqNp1P1p/1P1P4/2P2R2/P5PP/4R1K1 w k -
>Suche nach Matt in 9 ...  (Hash=384MB)
>Suche abgeschlossen ...  (Zeit=2029.28s)
>Kein Matt in 9 gefunden !  (33:49)
>
>Best regards,
>Franz.

Yes, you are right.  Sorry for the confusion.
My current version has a bug (I have made substantial changes recently).
Now searching for the problem cause...

Cheers,
Heiner



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