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Subject: Re: Is this queen sacrifice sound? (OT)

Author: Robin Smith

Date: 22:57:47 01/07/06

Go up one level in this thread


On January 07, 2006 at 03:35:00, Uri Blass wrote:

>On January 07, 2006 at 03:24:37, Uri Blass wrote:
>
>>On January 06, 2006 at 19:07:39, Robin Smith wrote:
>>
>>>On January 06, 2006 at 05:37:44, Vincent Lejeune wrote:
>>>
>>>>
>>>>BTW, I prepare some other very hard test positions mainly from CCC archives.
>>>>I've about 25 positions now , I'll post them next week.
>>>>
>>>>May be Rybka Winfinder will show some surprising results here...
>>>
>>>Here is another position for your database.
>>>[D] r1qr2k1/pb2bpp1/1p2p2p/2p4n/3P1B2/2PB1N2/PP2QPP1/1K1R2R1 w - - 0 16 bm
>>>16.Bxh6
>>>
>>>This is from a correspondence game I played many years ago. It would be
>>>interesting to see how programs do today, but when I tried Rybka Winfinder on it
>>>using my 2 year old laptop it still was not solved after several hours. The
>>>position 1 move earlier is absurdly hard for computers.
>>>
>>>-Robin
>>
>>I do not have rybka winfinder but maybe rybka slightly positional is better
>>here.
>>
>>with 512 mbytes hash
>>After more than 30 minutes of analysis it considers Bxh6 at least in the last 12
>>minutes(it does not choose this move but I see it in the analysis window for a
>>long time)
>>
>>New game
>>[D]r1qr2k1/pb2bpp1/1p2p2p/2p4n/3P1B2/2PB1N2/PP2QPP1/1K1R2R1 w - - 0 1
>>
>>Analysis by Rybka 1.0 Beta 32-bit:
>>
>>1.Bd2
>>  =  (0.05)   Depth: 3   00:00:00
>>1.Bd2
>>  =  (-0.12)   Depth: 4   00:00:00
>>1.Be3
>>  =  (-0.04)   Depth: 4   00:00:00
>>1.Be3 Nf6
>>  =  (0.01)   Depth: 5   00:00:00
>>1.Be3 Nf6 2.Ne5
>>  =  (0.00)   Depth: 6   00:00:00  11kN
>>1.Be3 Qc7 2.Ne5 Nf6
>>  =  (-0.14)   Depth: 7   00:00:00  27kN
>>1.Be3 Qc7 2.Ne5 Nf6 3.Rh1
>>  =  (-0.19)   Depth: 8   00:00:01  61kN
>>1.Bd2 Qc7 2.Ne5 Nf6 3.dxc5
>>  =  (-0.06)   Depth: 8   00:00:02  107kN
>>1.Bd2 Qc7 2.Ne5 Nf6 3.Bf4 cxd4
>>  =  (-0.24)   Depth: 9   00:00:02  155kN
>>1.Be3 Qc7 2.g3 Nf6 3.dxc5 bxc5 4.Bf4
>>  =  (-0.22)   Depth: 9   00:00:03  191kN
>>1.Be5 Nf6 2.g4 Nd7 3.Bf4 Qc6
>>  =  (-0.16)   Depth: 9   00:00:05  268kN
>>1.Be5 Nf6 2.g4 Nd5 3.Rh1 Qc6 4.Rh3
>>  =  (-0.20)   Depth: 10   00:00:10  502kN
>>1.Bh2 Nf6 2.g4 Bxf3 3.Qxf3 cxd4 4.cxd4 Nd5 5.Be5
>>  =  (-0.08)   Depth: 10   00:00:15  741kN
>>1.Bh2 Nf6 2.g4 Bxf3 3.Qxf3 cxd4 4.cxd4 Nd5 5.Qe4 g6
>>  =  (-0.13)   Depth: 11   00:00:17  869kN
>>1.Bh2 Nf6 2.g4 Bxf3 3.Qxf3 cxd4 4.cxd4 Nd5 5.Qe4 g6
>>  =  (-0.16)   Depth: 12   00:00:26  1336kN
>>1.Be5 Nf6 2.g4 Nd7 3.Bf4 Qc6 4.Rg3 c4 5.Bxc4
>>  =  (-0.05)   Depth: 12   00:00:52  2477kN
>>1.Be5 Qc6 2.Rh1 Nf6 3.Rh4 a5 4.Bb5 Qc8 5.Bd3 Bd5
>>  =  (-0.11)   Depth: 13   00:01:37  4695kN
>>1.Be5 Qc6 2.Nd2 Nf6 3.dxc5 bxc5 4.Bb5 Qb6 5.Bd3 Bd5
>>  =  (-0.17)   Depth: 14   00:03:14  9335kN
>>1.Bh2 Nf6 2.g4 Bxf3 3.Qxf3 cxd4 4.cxd4 Nd5 5.Qe4 g6
>>  =  (-0.02)   Depth: 14   00:04:30  12834kN
>>1.Bh2 Nf6 2.g4 Bxf3 3.Qxf3 cxd4 4.cxd4 Nd5 5.Qe4 g6
>>  =  (-0.13)   Depth: 15   00:05:49  16231kN
>>1.Bh2 Nf6 2.g4 cxd4 3.Nxd4 Nd5 4.Be5 Bg5 5.Be4 Nf4
>>  =  (-0.12)   Depth: 16   00:09:48  27110kN
>>
>>(,  07.01.2006)
>
>
>As I predicted
>I get the following line
>
>1.Bxh6 cxd4 2.Nxd4 Nf6 3.Bf4
>  ±  (0.75)   Depth: 16   00:39:24  97218kN
>
>(,  07.01.2006)
>
>I do not have rybka win finder but it is probably slower based on Robin Smith's
>post
>
>Uri

Actually I'm not sure WinFinder will be slower; at the present time I only have
access to a somewhat old laptop. Your machine is undoubtedly faster. The other
thing is that I used default WinFinder settings. If I used a smaller threshold
to define a "win" I think WinFinder would be quicker ... WinFinder pauses for
very long times on Bxh6, without ever selecting it, for several plies.

-Robin



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