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Subject: Re: Ok, but what about Nxg7 John

Author: John Merlino

Date: 09:23:56 08/10/05

Go up one level in this thread


On August 09, 2005 at 21:13:58, K. Burcham wrote:

>On August 09, 2005 at 18:44:03, John Merlino wrote:
>
>>CM9_R1 on an AMD 2500 finds Nxh6+ in five seconds, and finds Rg5+ in less than
>>one second.
>>
>>jm
>
>
> [D] r3rbk1/3q1pp1/p1b2n1p/npp1pN2/8/2PPB1NP/PPBQ1PP1/R3R1K1 w - - 0 1
>
>Shredder 9.1 UCI:
>
>1.a3
>  ²  (0.32)   Depth: 14/38   00:01:02  28333kN
>1.a3 Qd5
>  ²  (0.32)   Depth: 14/38   00:01:12  33034kN
>1.Nxg7
>  ²  (0.33)   Depth: 14/38   00:01:25  39661kN
>1.Nxg7
>  ²  (0.68)   Depth: 14/38   00:01:27  40416kN
>1.Nxg7 Qd5 2.f3 Bxg7 3.Bxh6 e4 4.fxe4 Bxh6 5.Qxh6 Qe5 6.Nf5 Nh7 7.d4 cxd4 8.cxd4
>Qf6 9.Qh5 Nc4 10.Rab1
>  ±  (0.80)   Depth: 14/38   00:01:33  43793kN
>1.Nxg7 Bxg7 2.Bxh6 Nh7 3.Bxg7 Kxg7 4.d4 e4 5.Qf4 cxd4 6.Nf5+ Kh8 7.Nxd4 Nc4
>8.Nxc6 Qxc6 9.Bxe4
>  ±  (0.94)   Depth: 15/40   00:01:46  50104kN
>1.Nxg7 Bxg7
>  ²  (0.69)   Depth: 16/40   00:02:03  58747kN
>1.Nxg7 Bxg7 2.Bxh6 Nh7 3.Bxg7 Kxg7 4.d4 Re6 5.Bf5 Qd5 6.f3 exd4 7.Nh5+ Kh8
>8.Bxe6 Qxh5 9.cxd4 fxe6 10.Qxa5 cxd4
>  ²  (0.51)   Depth: 16/42   00:02:15  64805kN
>1.Nxg7 Bxg7
>  ±  (0.76)   Depth: 17/42   00:04:00  115320kN
>1.Nxg7 Bxg7 2.Bxh6 Nh7
>  ±  (0.76)   Depth: 17/44   00:04:17  124076kN
>1.Nxg7 Bxg7
>  ±  (1.01)   Depth: 18/50   00:06:56  202826kN
>1.Nxg7 Bxg7 2.Bxh6 Nh7 3.Bxg7 Kxg7 4.b4 cxb4 5.cxb4 Bxg2 6.Kxg2 Nc6 7.d4 Nxd4
>  ±  (1.02)   Depth: 18/50   00:07:29  220476kN
>1.Nxg7 Bxg7 2.Bxh6 Nh7 3.Bxg7 Kxg7 4.d4 Re6 5.Bf5 exd4 6.Bxe6 fxe6 7.cxd4 Qd5
>  ±  (0.93)   Depth: 19/53   00:11:41  345895kN
>1.Nxg7 Bxg7 2.Bxh6 Nh7 3.Bxg7 Kxg7 4.b4 cxb4 5.cxb4 Bxg2 6.Kxg2 Nc6 7.Bd1 Nd4
>8.Kh2 Kh8 9.Qh6 f5 10.Rc1
>  ±  (1.04)   Depth: 20/57   00:22:56  684414kN
>
>
>Deep Fritz 8:
>
>1.Qe2 Rad8 2.Rad1 Nd5 3.Qg4 Nxe3 4.Nxe3 Qxg4 5.Nxg4 Bd6 6.Nf5 Bc7 7.Nge3 Re6
>8.d4 cxd4
>  =  (-0.20)   Depth: 13/39   00:01:01  78362kN
>1.Nxh6+!
>  =  (-0.19)   Depth: 13/40   00:02:41  211601kN
>1.Nxh6+!
>  =  (-0.04)   Depth: 13/40   00:02:47  218940kN
>1.Nxh6+ gxh6 2.Bxh6 Nh7 3.Bxf8 Rxf8 4.Rxe5 Nc4 5.Rg5+ Kh8 6.Qf4 Nxb2 7.Rxc5 Rac8
>  =  (0.01)   Depth: 13/40   00:02:54  228110kN
>1.Nxh6+ gxh6 2.Bxh6 Nh7 3.Bxf8 Rxf8 4.Rxe5 Nc4 5.Rg5+ Kh8 6.Qf4 Nxb2 7.Rxc5 Rac8
>  =  (0.01)   Depth: 14/41   00:03:30  278154kN
>1.Nxh6+ gxh6 2.Bxh6 Nh7 3.Bxf8 Rxf8 4.Rxe5 Nc4 5.Rg5+ Kh8 6.Qf4 Nxb2 7.Rxc5 Bb7
>8.Qf5 Qxf5
>  =  (0.19)   Depth: 15/44   00:06:04  489859kN
>1.Nxh6+ gxh6 2.Bxh6 Nh7 3.Bxf8 Rxf8 4.Rxe5 Nc4 5.Rg5+ Kh8 6.Qf4 Nxb2 7.Rxc5 Bb7
>8.Qf5 Qxf5
>  =  (0.19)   Depth: 16/45   00:12:21  1006016kN
>1.Nxg7!
>  =  (0.19)   Depth: 16/49   00:31:20  2520267kN
>1.Nxg7 Bxg7 2.Bxh6 Nh7 3.Bxg7 Kxg7 4.d4 e4 5.Qf4 cxd4 6.Nf5+ Kh8 7.Nxd4 Bd5
>  =  (0.23)   Depth: 16/49   00:34:11  2753559kN

After forcing 1.Nxg7 Bxg7 2.Bxh6 Nh7 3.Bxg7 Kxg7, the eval is only slightly
higher (about 0.1 better) than it is in the initial position for 1.Nxh6+. But if
I force the same number of moves with 1.Nxh6+ gxh6 2.Bxh6 Nh7 3.Bxf8 Rxf8, then
the eval is almost a half-pawn better for Nxh6+.

I think both moves accomplish pretty much the same thing, and it is really just
a matter of the engine's style as to how it wants to accomplish it.

jm



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