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Subject: Position from yesterday, Rxc7!!, problem for all Rybka versions.

Author: Andreas St.

Date: 10:00:39 02/09/06

Hi,
yesterday i posted this position:

2r5/2pR1pk1/p1P3p1/P2K4/5P1p/5P1P/8/8 w - - 0 1

and some users said, Rybka finds the solution.

>Not Rybka 13b, but Rybka 1.0 Beta 32-bit (the first version!!!)
>Best regards,
>Orlando

>Rybka 1.0 Beta 32-bit, sees Rxc7 quickly. I've no idea how the person testing
>whatever version had this failure.

>Terry


What do you mean??? No Rybka version finds the only winning move Rxc7!
If you analyse long enough, you will see, all Rybka versions prefers f5.
At the latest after one hour no Rxc7, but f5!
And look at the score of rybka. He sees nothing in this position.
Fritz 9 for example has +3.50 after 42sec.
Shredder 9 after 0 sec.! After 17sec. Score +3.05

Mephisto Vancouver finds the correct move in 8min 45sec!
Fritz, Junior, Shredder.... have no problems to find the correct move Rxc7 with
a high score about +4:

Here a winning line (white wins quickly):

1.Rxc7!! Rxc7 2.Kd6 Rc8 3.Kd7 Rh8 4.c7 Kf6 5. c8Q Rxc8 6.Kxc8 and white wins!


Here an analysis of Rybka (all Pentium IV, 3,28 GHZ, 256MB hash)
Rybka 1.0 Beta 32-bit:

1.Kd4 Kf6 2.Kc4 Ke6 3.Kc5 Kf6 4.Kd4
  ²  (0.32)   Tiefe: 10   00:00:00  11kN
1.Kd4 Kf6 2.Kc4 Ke6 3.Kc5 Kf6 4.Kd4 Ke6
  =  (0.15)   Tiefe: 11   00:00:00  25kN
1.Kd4 Kf6 2.Kc4 Ke6 3.Kc5 Kf6 4.Kd4 Ke6 5.Kc4 Kf6
  =  (0.25)   Tiefe: 12   00:00:00  41kN
1.Kd4 Kf6 2.Kc4 Ke6 3.Kc5 Kf6 4.Kd4 Ke6 5.Kc4 Kf6
  =  (0.18)   Tiefe: 13   00:00:00  63kN
1.Kd4 Kf6 2.Kc4 Ke6 3.Kd3 Kf6 4.Kd4 Ke6 5.Kc4 Kf6
  =  (0.18)   Tiefe: 14   00:00:00  150kN
1.Kd4 Kf6 2.Kc4 Ke6 3.Kd3 Kf6 4.Kd4 Ke6 5.Kc4 Kf6
  =  (0.19)   Tiefe: 15   00:00:00  217kN
1.Kd4 Kf6 2.Kc5 Ke6 3.Kc4 Kf6 4.Kd3 Ke6 5.Ke4 Kf6
  =  (0.09)   Tiefe: 16   00:00:02  594kN
1.Kd4 Kf6 2.Kc5 Ke6 3.Kc4 Kf6 4.Kd3 Ke6 5.Ke4 Kf6
  =  (0.09)   Tiefe: 17   00:00:02  793kN
1.Txc7 Txc7 2.Kd6 Tc8 3.c7 Kf6 4.Kd7 Th8 5.c8D Txc8
  ±  (0.93)   Tiefe: 17   00:00:03  1333kN
1.Txc7 Txc7 2.Kd6 Tc8 3.c7 Kf6 4.Kd7 Th8 5.c8D Txc8
  ±  (1.00)   Tiefe: 18   00:00:03  1580kN
1.Txc7 Txc7 2.Kd6 Tc8 3.c7 Kf6 4.Kd7 Th8 5.c8D Txc8
  ±  (0.88)   Tiefe: 19   00:00:04  1789kN
1.Txc7 Txc7 2.Kd6 Tc8 3.c7 Kf6 4.Kd7 Txc7+ 5.Kxc7 Ke6
  ±  (1.04)   Tiefe: 20   00:00:06  2980kN
1.Txc7 Txc7 2.Kd6 Tc8 3.Kd7 Ta8 4.c7 Kf8 5.c8D+ Txc8
  ±  (1.04)   Tiefe: 21   00:00:08  3828kN
1.Txc7 Txc7 2.Kd6 Tc8 3.Kd7 Ta8 4.c7 Kf8 5.c8D+ Txc8
  ±  (0.97)   Tiefe: 22   00:00:12  4906kN
1.f5 g5 2.Txc7 Txc7 3.Kd6 Tc8 4.c7 Kf6 5.Kd7 Th8
  ±  (1.28)   Tiefe: 22   00:01:18  22266kN
1.f5 g5 2.Txc7 Txc7 3.Kd6 Tc8 4.c7 Kf6 5.Kd7 Th8
  ±  (1.39)   Tiefe: 23   00:01:45  27645kN
1.f5 g5 2.Ke5 Te8+ 3.Kd4 Tc8 4.Ke3 Te8+ 5.Kf2 Kf6
  ±  (1.04)   Tiefe: 24   00:03:53  49182kN
1.f5 g5 2.Ke5 Te8+ 3.Kd4 Tc8 4.Ke3 Te8+ 5.Kf2 Kf6
  ±  (0.90)   Tiefe: 25   00:05:21  64774kN
1.f5 g5 2.Ke5 Te8+ 3.Kd4 Tc8 4.Ke3 Te8+ 5.Kd3 Tc8
  ±  (0.87)   Tiefe: 26   00:10:04  113829kN
1.f5 g5 2.Ke5 Te8+ 3.Kd4 Tc8 4.Ke3 Te8+ 5.Kf2 Kf6
  ±  (0.88)   Tiefe: 27   00:23:52  228381kN
1.f5 g5 2.Ke5 Te8+ 3.Kd4 Tc8 4.Ke3 Te8+ 5.Kf2 Kf6
  ±  (0.84)   Tiefe: 28   00:35:36  318508kN
1.Txc7 Txc7 2.Kd6 Tc8 3.Kd7 Ta8 4.c7 Kf8 5.c8D+ Txc8
  ±  (0.94)   Tiefe: 28   00:41:48  468953kN
1.Txc7 Txc7 2.Kd6 Tc8 3.Kd7 Ta8 4.c7 Kf8 5.c8D+ Txc8
  ±  (0.88)   Tiefe: 29   00:47:24  555387kN
1.Txc7 Txc7 2.Kd6 Tc8 3.Kd7 Ta8 4.c7 Kf8 5.c8D+ Txc8
  ±  (0.88)   Tiefe: 30   01:06:30  757475kN
1.Txc7 Txc7 2.Kd6 Tc8
  ±  (1.03)   Tiefe: 31   01:31:05  1042592kN
1.Txc7 Txc7 2.Kd6 Tc8
  +-  (1.47)   Tiefe: 32   02:32:48  1626426kN
1.Txc7 Txc7 2.Kd6 Tc8 3.Kd7
  +-  (1.49)   Tiefe: 33   04:45:24  2788067kN

Rybka finds Rxc7 the best after 41 min, but only with a score +0.94.
So he don't see a win!
I aborted with Rybka 13b after one hour, he wants f5.

Re: Position from yesterday, Rxc7!!, problem for all Rybka versions. Mike Byrne 16:07:30 02/10/06
- Re: Position from yesterday, Rxc7!!, i think that Rxc7 does not win Oreopoulos Kostas 02:25:45 02/12/06
  - Re: Position from yesterday, Rxc7!!, i think that Rxc7 does not win Uri Blass 07:52:45 02/12/06
Re: Position from yesterday, Rxc7!!, problem for all Rybka versions. Uri Blass 14:27:35 02/09/06
- Re: Position from yesterday, Rxc7!!, problem for all Rybka versions. Terry McCracken 16:03:23 02/09/06
  - Re: Position from yesterday, Rxc7!!, problem for all Rybka versions. Robin Smith 17:04:23 02/09/06
    - Re: Position from yesterday, Rxc7!!, problem for all Rybka versions. Terry McCracken 20:35:08 02/09/06
  - Re: Position from yesterday, Rxc7!!, problem for all Rybka versions. Dann Corbit 16:33:38 02/09/06
    - Re: Position from yesterday, Rxc7!!, problem for all Rybka versions. Uri Blass 17:04:57 02/09/06
      - Re: Position from yesterday, Rxc7!!, problem for all Rybka versions. Robin Smith 17:15:23 02/09/06
Re: Position from yesterday, Rxc7!!, problem for all Rybka versions. Terry McCracken 13:40:28 02/09/06
- Is black really lost for sure??????!!!!!!!! Bernardo Wesler 15:27:10 02/09/06
  - Re: Is black really lost for sure??????!!!!!!!! Terry McCracken 15:53:21 02/09/06
    - Re: Is black really lost for sure??????!!!!!!!! Mark Ryan 16:31:37 02/09/06
      - Re: Is black really lost for sure??????!!!!!!!! Terry McCracken 20:53:24 02/09/06
- Re: Position from yesterday, Rxc7!!, problem for all Rybka versions. Steve Maughan 14:03:15 02/09/06
  - Re: Position from yesterday, Rxc7!!, problem for all Rybka versions. Terry McCracken 15:37:59 02/09/06
    - Re: Position from yesterday, Rxc7!!, problem for all Rybka versions. Steve Maughan 16:41:26 02/09/06
      - Re: Position from yesterday, Rxc7!!, problem for all Rybka versions. Mark Ryan 17:02:55 02/09/06
        
        Re: Position from yesterday, Rxc7!!, problem for all Rybka versions. Steve Maughan 17:27:02 02/09/06
        
        Re: Position from yesterday, Rxc7!!, problem for all Rybka versions. Robin Smith 17:24:32 02/09/06
        
        Re: Position from yesterday, Rxc7!!, problem for all Rybka versions. Terry McCracken 20:51:11 02/09/06
        
        Re: Thanks. Mark Ryan 17:37:39 02/09/06
Re: Position from yesterday, Rxc7!!, problem for Fritz 9 also Albert Silver 12:30:44 02/09/06
- Re: Position from yesterday, Rxc7!!, problem for Fritz 9 also Andreas St. 17:20:41 02/09/06
Re: Position from yesterday, Rxc7!!, problem for all Rybka versions. Andreas St. 10:03:59 02/09/06

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