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Subject: Re: Tiger doesn't understand; Fritz 6 not great either

Author: Roy Eassa

Date: 11:47:51 08/26/01

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On August 26, 2001 at 14:45:40, Roy Eassa wrote:

>On August 26, 2001 at 14:40:33, Roy Eassa wrote:
>
>>[D] 8/2r1k2p/p3p1p1/3r1p2/8/1P3PP1/P2RK2P/3R4 b - -
>>
>>I reached this position as white recently, and after the game I used Gambit
>>Tiger 2.0 to help analyze.  What occurred in the game was:
>>
>>1... Rcd7(?) 2. Rxd5 Rxd5?? 3. Rxd5 exd5
>>
>>after which I believe white should win (which I did).  I believe it's very bad
>>for black to trade off both pairs of rooks, and best to avoid allowing white to
>>exchange even one pair of rooks here because of isolating black's pawn.
>>
>>It appears that Gambit Tiger 2 on my Athlon 1.2 GHz does not really understand
>>that after move white's move 3 above, white should win.  And it believes the
>>position is essentially equal after white's move 2.
>>
>>Here is its analysis after black's move 1:
>>
>>00:00:00.9	0.22	9	168541	h3 Kf6 Rxd5 exd5 Rc1 Ke6 Kd3 f4 Rc6+ Rd6 Rxd6+ Kxd6
>>00:00:00.3	0.16	9	184134	h3 Rxd2+ Rxd2 Rxd2+ Kxd2 e5 Ke3 Ke6 g4 fxg4 fxg4 h5 a3
>>hxg4 hxg4
>>00:00:01.9	0.12	10	445643	h3 Rxd2+ Rxd2 Rc7 Kd1 e5 Rc2 Rxc2 Kxc2 e4 fxe4 fxe4
>>Kc3
>>00:00:01.4	0.16	10	710893	Rxd5 Rxd5 Rc1 Kd6 Rc8 Rc5 Rxc5 Kxc5 Kd3 Kb4 h4 Ka3
>>00:00:02.8	0.16	11	905910	Rxd5 Rxd5 Rc1 Kd6 Rc8 Rc5 Rxc5 Kxc5 Kd3 Kd5 g4 e5 gxf5
>>gxf5
>>00:00:03.0	0.16	12	1519152	Rxd5 Rxd5 Rxd5 exd5 b4 Ke6 Ke3 Ke5 f4+
>>00:00:05.5	0.16	13	2286175	Rxd5 Rxd5 Rxd5 exd5 b4 Ke6 Ke3 Ke5 f4+ Kd6 a4 Ke6 Kd4
>>h6 b5 axb5 axb5
>>00:00:09.6	0.18	14	3833264	Rxd5 Rxd5 Rxd5 exd5 b4 Ke6 Ke3 h6 f4 g5 a3 gxf4+ Kxf4
>>d4 Kf3 d3 Ke3
>>00:00:18.1	0.20	15	7566502	Rxd5 Rxd5 Rxd5 exd5 b4 Kd6 Ke3 g5 f4 gxf4+ Kxf4 d4 a3
>>h5 Kf3 d3 Ke3
>>
>>
>>but after 2. Rxd5, suddenly Tiger prefers black to recapture with the pawn
>>rather than the rook, and its evaluation becomes worse for black.
>>
>>Non-Gambit Tiger behaves very similarly.
>>
>>Is the lack of endgame knowledge in me or the program, or is it something else?
>>
>>(Using 96MB hash; Not using table bases.)
>
>
>Junior 6 takes 41 seconds after black's move 2 to even realize that white should
>exchange the secon pair of rooks, and thinks the resulting advantage is tiny:
>
>3.Rc1 Re5+ 4.Kd3 Rd5+
>  =  (0.07)   Depth: 6   00:00:00
>  =  (0.00)   Depth: 19   00:00:35  34856kN
>3.Rxd5 exd5 4.b4 Kd6 5.a4 Kc7 6.Kd3 Kc6 7.Kd4 h6 8.b5+
>  =  (0.08)   Depth: 19   00:00:41  39945kN
>  =  (0.08)   Depth: 19   00:00:41  39945kN


Fritz 6 doesn't exactly dazzle with its fast understanding, after black's move
2:

3.Rxd5--
  µ  (-0.72)   Depth: 1/3   00:00:00
  µ  (-0.72)   Depth: 1/3   00:00:00
3.f4 Ra5 4.a4 e5
  ³  (-0.56)   Depth: 1/4   00:00:00
  =  (-0.09)   Depth: 4/8   00:00:00
3.Rd3--
  =  (-0.06)   Depth: 4/9   00:00:00  1kN
  ³  (-0.47)   Depth: 9/18   00:00:00  154kN
3.f4! Rxd1 4.Kxd1 Kf6 5.h4 e5 6.fxe5+ Kxe5 7.Ke2 h6
  ³  (-0.44)   Depth: 9/18   00:00:00  169kN
  ³  (-0.34)   Depth: 9/18   00:00:00  182kN
3.Rc1 Re5+ 4.Kd3 Rd5+ 5.Ke3 Re5+ 6.Kf2 Kd6 7.Rc8 Rc5
  ³  (-0.31)   Depth: 9/19   00:00:00  228kN
  =  (0.00)   Depth: 13/30   00:00:16  12674kN
3.Rxd5 exd5 4.Ke3 Kd6 5.Kd4 g5
  =  (-0.12)   Depth: 13/30   00:00:19  14134kN
  =  (0.19)   Depth: 15/25   00:00:35  23503kN




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