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Subject: Re: Does any program except Brutus play this sacrifice?

Author: Drexel,Michael

Date: 22:51:46 09/15/03

Go up one level in this thread


On September 15, 2003 at 18:37:27, Mike Byrne wrote:

>On September 15, 2003 at 13:23:14, Drexel,Michael wrote:
>
>>On September 15, 2003 at 12:55:53, Tord Romstad wrote:
>>
>>>On September 15, 2003 at 12:29:52, Drexel,Michael wrote:
>>>
>>>>On September 15, 2003 at 12:25:25, Tord Romstad wrote:
>>>>
>>>>>On September 14, 2003 at 17:58:56, Roy Eassa wrote:
>>>>>
>>>>>>[d] 4r1k1/p4ppp/1p1q1n2/1Pb1n3/8/1N4P1/PB3PBP/2RQ2K1 b - - 0 1
>>>>>>Brutus played ...Bxf2+
>>>>>>
>>>>>>1... Bxf2+!?
>>>>>
>>>>>Like Will Singleton, I think many (perhaps even most) programs will
>>>>>play Bxf2, but I think finding a win for white will take a very long
>>>>>time.
>>>>>
>>>>>Gothmog 0.3.0 plays Bxf2 after less than 4 seconds, but it's a purely
>>>>>speculative sacrifice.  The score is not at all convincing:
>>>>
>>>>It is not speculative, it is almost forced. Everything else is very bad for
>>>>white.
>>>
>>>Sorry, I should have been clearer.  I meant that Gothmog plays Bxf2 as
>>>a speculative sacrifice, from a subjective point of view.  It does not
>>>see a win for black, but just gambles that black's attacking chances will
>>>be sufficient to compensate for the piece.
>>>
>>>Tord
>>
>>You are the programmer ...
>>
>>But if your program also sees in less than 4 seconds that
>>1... Nd3 is bad because of the forced
>>2. Nxc5 bxc5 3. Bf1 Re1 4. Qd2 Rxc1 5. Bxc1 c4 6. Qc3 Qd5 7. Bxd3 Qxd3
>>8. Qxd3 cxd3 (with clearly better endgame for white) then it would be quite an
>>achievement.
>>All top programs need at least several minutes to find it.
>>
>>Michael
>
>
>Crafty 19.04 SE Morphy needs 16 seconds to see the line Nd3 above
>
>
>         13    16.36   0.31   1. ... Nd3 2. Nxc5 bxc5 3. Bf1 Re1
>                              4. Qd2 Rxc1 5. Bxc1 c4 6. Qc3 Qd5 7.
>                              Bxd3 Qxd3 8. Qxd3 cxd3 9. Bd2
>         13->  16.36   0.31   1. ... Nd3 2. Nxc5 bxc5 3. Bf1 Re1
>                              4. Qd2 Rxc1 5. Bxc1 c4 6. Qc3 Qd5 7.
>                              Bxd3 Qxd3 8. Qxd3 cxd3 9. Bd2
>         14    22.25     --   1. ... Nd3
>         14    34.20   1.07   1. ... Nd3 2. Nxc5 bxc5 3. Bf1 Re1
>                              4. Qd2 Rxc1 5. Bxc1 c4 6. Qc3 Qd5 7.
>                              Bxd3 Qxd3 8. Qxd3 cxd3 9. Be3 Kf8 10.
>                              Bxa7?? d2 -+

>
>but after 4 minutes - it gets more favorable with Nd3, prefering 6.Nb2 over
>6.Qc3 ...but it always likes Bxf2 best

Crafty 19.03 prefers 6.Bb2 a long time even here:

[D] 6k1/p4ppp/3q1n2/1P6/2p5/3n2P1/P2Q1P1P/2B2BK1 w - - 0 6

After almost 10 minutes it finally switches to 6.Qc2 which is as strong as
6.Qc3. Other freebies like Aristarch or Yace have big problems here too.

Shredder 7.04 and Fritz 8 are much faster. They solve it instantly.

So what is the reason?
The white King will be very active in a couple of moves.

Michael


>  16->   4:51   0.18   1. ... Nd3 2. Nxc5 bxc5 3. Bf1 Re1
>                       4. Qd2 Rxc1 5. Bxc1 c4 6. Bb2 Ne8 7.
>                       Bc3 Qd5 8. a4 Nd6 9. Bg2 Ne4 10. Qe3
>                       Ndxf2 11. Qxa7



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