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Subject: Re: If you want to solve one mate...

Author: Heiner Marxen

Date: 03:41:36 04/17/01

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On April 14, 2001 at 11:25:53, Paul wrote:

>On April 14, 2001 at 10:37:06, leonid wrote:
>
>>Hello!
>>
>>If you like to solve one mate (or if you want to selebrate Passover by
>>crucifying your solfware) then this position is just for you:
>>
>>[D]1qRr2bk/Q1P1q1bq/4Qn1N/3qq1Qn/KRQ1Qq1N/B2B4/6Qq/2q3r1 w - -
>>
>>Please, indicate your result.
>>
>>Thanks,
>>Leonid.
>
>The first thing Pretz says is this (mate in 13):
>
>11:34 WM13 10 Qxg8+ Qhxg8 Ng6+ Kh7 Nxe5+ Kh8 Ng6+ Kh7 Nxe7+ Kh8 Qh7+ Qxh7
>cxd8=Q+ Ne8 Qxe8+ Bf8 Qad4+ Qbe5 Qdxe5+ Qfxe5 Qxf8+ Qhg8 Qfxg8+ Qxg8 Rxg8#
>
>Will try some different extensions later ...
>
>Groetjes,
>Paul

That is interesting, since according to Chest this is indeed a mate in 13.
After 5 hours (K7/600, 350MB hash) Chest gives this PV:

Qxg8+ Qhxg8 Ng6+  Kh7  Nxe5+ Kh8   Ng6+   Kh7   Nxe7+  Kh8   Ng6+   Kh7   Ne5+
Nxe4  Qgxe4+ Kh8   Qh7+   Qxh7 cxd8Q+ Qf8   Qxf8+  Qhg8 Qxg8+  Qxg8 Nhf7#

The effective branching factor was quite good for Chest, between 2.7 and 5
most of the time (for a full move).  But ETC (enhanced transposition cutoff)
was extremely useless (5% hit rate).  I have no idea, why.

Hi Paul, you are right, I've been away for a week, visiting my brother's
family in Switzerland, but I did not expect someone to take notice  ;-)

Now I will scan through a full week of CCC...

Cheers, Heiner



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