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Subject: Re: Rebel's anti-GM option

Author: jonathan Baxter

Date: 16:59:22 06/23/98

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On June 23, 1998 at 18:25:49, Amir Ban wrote:

>On June 23, 1998 at 16:19:32, Bruce Moreland wrote:
>
>>
>>On June 23, 1998 at 09:45:45, Moritz Berger wrote:
>>
>>
>>>I took the example position on Eds page to test the 'anti GM' qualitities of
>>>some other programs (P233MMX, NT 4.0, 128 MB RAM). Especially Junior's
>>>performance is frightening (Rxe6 at 4.5 ply after 2", after 4" even with
>>>positive evaluation!).
>>>
>>>No question that Anti-GM-Rebel is now among the very best programs in this
>>>position, so Ed clearly is on the right track ...
>>
>>>2rqk2r/pb1nbp1p/4p1p1/1B1n4/Np1N4/7Q/PP3PPP/R1B1R1K1 w k - 0 1
>>
>>>Junior 4.6 32768 KB hash tables
>>>00:04 9 semiply 0.04 Rxe6!
>>>
>>>Fritz 5.01 98304 KB hash tables
>>>00:04 7/28 -1.13   Rxe6!
>>
>>>Hiarcs 6 (Fritz engine) 98304 KB hash tables
>>>01:42 7/23 -0.88   Rxe6!
>>
>>>Crafty v15.14, hash table memory = 48M bytes, pawn hash table memory = 10M
>>
>>>                9     3:49     ++   1. Rxe6!!
>>
>>>Shredder 2.0
>>
>>> 9.07   5:24.71  -0.15++ Rxe6 (17.259.985)
>>
>>Ferret:
>>
>>Never, I hope.
>>
>>I get a fail high a few minutes into this, but the re-search fails low.
>>
>>I like aggressive play, and I like speculative play that works, but I think that
>>programs are seeing something here that doesn't exist.
>>
>>Crafty likes the position after Rxe6, it ends up with a positive score.  Bob
>>wasn't around so I could ask him, but I did some experiments and got permission
>>retroactively.
>>
>>I set up the position after Rxe6 fxe6 and asked Crafty to play white (30 0, with
>>Crafty on a 4 processor P6/200 and mine on a 533 mhz Alpha).  It was happy for a
>>couple of moves then the bottom fell out.  It tried to throw more fuel on the
>>fire and ended up a rook down with nothing to show for it.
>>
>>I reversed the colors and tried again, and mine started out at like -1.7 and
>>stuck there into an ending where it as down the exchange for a pawn, and had
>>worse development.
>>
>>I am hoping that the reason my program won't play this is that it sees that the
>>bottom falls out.
>>
>>I would be happy to be shown a line that has any promise for white.  If someone
>>thinks that this really does win, or at least offers good counterplay, please
>>post a line.
>>
>
>The critical line is:
>
>1.Rxe6 fxe6 2.Nxe6 Qa5 3.Bxd7+ Kxd7! 4.Nc5+ Ke8 5.Qd7+ Kf7 6.Nxb7 Rc7 7.Nd6+ Kg7
>8.Ne8+ Rxe8 9.Qxe8 Nf6!
>
>The rook sac is not at all speculative. It's just wrong. Your eval should be a
>significant plus for white at at least two points in it, but this doesn't hold
>because black has these counter-resources. Black has only one defense, but it
>works. The hard part for black is seeing 3...Kxd7. 3...Kf7 is a dead loss.
>
>
>>My own analysis shows a nasty check or two, then black is simply up material.
>>
>
>No, there's more to it as you can see in the line. I don't understand how your
>program can dismiss this line without passing through intermediate depths where
>it would think it works.
>
>
>>Additionally, I would like to ask those who report when they find this move to
>>see how long their programs hold the move.  Do they stick with it for 24 hours?
>>
>
>It takes me 7 minutes on P-II 300 to play 1... fxe6.

KnightC, in 4 mins, plays 1. Rxe6 (-1.43) and stays with Rxe6 for at least 10
more minutes. The PV is e1e6 f7e6 d4e6 d8a5 b5d7 e8d7 e6c5 d7e8 h3d7 e8f7 c5b7
d5f6

Jon



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