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Subject: Re: classical bishop sac, which program finds it in acceptable time?

Author: Dan Ellwein

Date: 15:00:52 09/24/00

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On September 24, 2000 at 17:09:09, Vincent Diepeveen wrote:

>On September 24, 2000 at 16:06:57, Dan Ellwein wrote:
>
>>On September 24, 2000 at 10:42:01, Harald Faber wrote:
>>
>>>I'd suggest 30mins.
>>>
>>>[D]rnbqr1k1/pp2bppp/4p3/2ppP3/3P3P/2NB1N2/PPP2PP1/R2QK2R w KQ - bm Bd3h7;id
>>>Faber-Lautenschuetz;
>>
>>Harold
>>
>>Can you give the move sequence after Bxh7...
>
>It's very deep to see, basically you need to start with
>
>Bxh7 kxh7 ng5 bxg5 hxg5 kg8 qh5 kf8 g6 ke7 gf rf8 dxc5
>
>And only then diep starts seeing the problems getting a draw score
>at ply=9, and desperately playing Na6 in the end with a near to
>draw score, most likely failing low the ply after it.
>g7 goes away f7 goes away,
>sacrafices on d5 in all mainlines, and after long castling white plays with
>some pieces more, but before you see those effectively penetrate the position
>you're another 10 ply further. After the above sequence i still have
>a draw score for Qa5 at ply==11, it's hard to blame evaluation, but that's
>only way to find this combination. Basically you need to get an optimistic
>score for white as the root position is optimistically evaluated for
>white. So black needs to see big troubles before it will consider playing
>Bxh7. 20 plies or so?
>
>>thanks

thanks Vincent for the analysis...

CM7 playing against itself starting with Bxh7 produces the following:

...     Kxh7
Ng5+    Kg8
Qh5     Bxg5
hxg5    Kf8
g6      Ke7
gxf7    Rf8
0-0-0   Nc6
dxc5    b6
Qg6     Rxf7
Rh7 (after this move the evaluation for White goes to > +2.00)
>>
>>PilgrimDan



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