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Subject: Re: One mate to solve...

Author: Angrim

Date: 13:40:28 07/07/01

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On July 06, 2001 at 18:30:08, Heiner Marxen wrote:

<snip>
>>>proved that move g5xg7 wins, 11 turns
>>>PN2:2020634 evals, 39222 expands, 13.15 seconds
>>>
>>>pv starts with g5xg7+ f7xg7 c4g8+ g7xg8 b3xg8+
>>>Angrim
>>
>>I tried to verify this, but failed.  I assume "11 turns" does mean a mate in
>>11 moves.  After the above 5 plies there is only one legal move left.
>>Hence I started Chest after 1.Qxg7+ Q7xg7 2.Qg8+ Qxg8 3.Qbxg8+ Bxg8, searching
>>for a mate in 8 (8 == 11-3).  But according to Chest, there is no mate in 8
>>(K7/600, 350 MB hash, 435 secs).  I have used this FEN:
>>R1N1N2k/2qqqqbb/1nQ2q1r/2Q2qQ1/1nQ2q2/1QQQQq1r/1BB5/K5QR w - -

starting with this fen, and applying the moves:
1.Qxg7+ Q7xg7 2.Qg8+ Qxg8 3.Qbxg8+ Bxg8 gives the position:
fen R1N1N1bk/2qqq3/1nQ2q1r/2Q2q2/1n3q2/2QQQq1r/1BB5/K5QR w - -
from which my program says that 4. Qxg8+ wins in 9 turns.
blacks reply Kxg8 is then forced
then 5. c8xe7+ is the next move.
fen R3N1k1/2qqN3/1nQ2q1r/2Q2q2/1n3q2/2QQQq1r/1BB5/K6R b - - 0 2
then Kf7 is fairly forced
then 6. c3xf6+ is the next move.(score win in 6 turns, don't check my math;)

Hope you can find the win from here, otherwise one of our programs
has a bug.

Angrim

>
>There is not even one in 9 moves, here (again, according to Chest).
>
>Heiner
>
>>Where did I go wrong?  Or did I misunderstand?
>>
>>Heiner



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