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Subject: Re: One mate to solve for Champions!

Author: Heiner Marxen

Date: 08:53:39 10/03/01

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On October 02, 2001 at 09:52:50, Paul wrote:

>On October 02, 2001 at 08:41:20, leonid wrote:
>
>>[D]kq4BK/pq4QQ/2qq1P2/1NnqBnN1/3PpP2/2P2r2/RQ4qr/RQ4bb w - -
>>
>>I have said that this position is for "Champions" only having in mind that some
>>people will try to solve it by brute force. Brute force is the only way to know
>>minimal nomber of moves that lead to mate. But it could be not all the time
>>easy. When I tried this position on two professional program, I was impressed.
>>On Celeron 600Mhz, and with 1M of hash, one expected to solve position in around
>>4000 years. Other, with no hash, after around 11000000000 years of thinking
>>expected to recognize shortest mate.
>>
>>Please indicate your result.
>>
>>Thanks,
>>Leonid.
>
>Hi Leonid,
>
>I just now started to look at both your positions, the simple one from yesterday
>and this one, and I think you have a bit of a twisted nomenclature!
>
>This one is the simple one, the other one is more difficult. Even if this one
>seems to be a mate in 12, and the other in 9. But maybe that's only the case for
>Pretz, I'm curious about LLchess.
>
>For this one I find a mate in 12 in 3 seconds by applying some gentle force:
>
>00:03 WM12 12 Rxa7+ Q8xa7 Rxa7+ Kb8 Rxb7+ Nxb7 Qf8+ Qc8 Qxc8+ Kxc8 Nxd6+ Nfxd6
>Be6+ Kd8 Qb6+ Ke8 Bd7+ Kf8 Bxd6+ Nxd6 Qb8+ Nc8 Qxc8#

Hi Leonid, Hi Paul!

Since 1BELCT has finished, and my PC is reassembled, its time for a mate... :-)

Chest confirms the above: Rxa7+ is the only key move for the shortest
solution. It gives nearly the same PV:

PV: Rxa7+ Q8xa7 Rxa7+ Kb8 Rxb7+ Nxb7 Qf8+ Qc8 Qxc8+ Kxc8 Nxd6+ Nfxd6 Be6+ Kd8
Qb6+ Ke8 Bd7+ Kf8 Bxd6+ Qxd6 Qxd6+ Nxd6 Ne6#

(9.5 minutes on a K7/600 with 350 MB hash).

Heiner


>With colors switched it's a mate in 2 ... ;)
>
>Groetjes,
>Paul



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