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Subject: Re: Passes pawn eval - test position

Author: Uri Blass

Date: 01:37:19 09/08/01

Go up one level in this thread


On September 07, 2001 at 17:19:07, José Carlos wrote:

>  Last night, in one of my test games, Averno played ...Bxf4 in this position
>(against another program):
>
>[D]4R3/p2r3r/1pNbRp2/2p2k1p/2P2PpP/PP4P1/K7/8 b - - 0 1
>
>  The game ended soon:
>
>57. gxf4 g3 58. Re2 Rhg7 59. Re1 g2 60. Rg1 Rd2+ 61. Ka1 Rf2
>62. Ree1 Kxf4 63. a4 Kg3 64. a5 Rc7 65. Nd8 bxa5 66. Kb1 Kxh4 67. Ka1 Kg3
>68. Kb1 h4 69. Ne6 Rc6 70. Nd8 Rb6 71. Ne6 Rxb3+
>{White resigns} 0-1
>
>  59. Re1 is a blunder, but I wonder if the sac is correct at all. It seems that
>59. Rg2 is good enough for white (Averno plays Bxf4 by eval, it doesn't see the
>pawn queening at all in search). Is my passed pawn eval too high here? What do
>other programs think?
>
>  Thanks in advance.
>
>  José C.
Junior7 on p200MMX
New position
4R3/p2r3r/1pNbRp2/2p2k1p/2P2PpP/PP4P1/K7/8 b - - 0 1

Analysis by Junior 7:

1...b5 2.cxb5
  ±  (1.04)   Depth: 3   00:00:00
1...a5 2.Re1
  ²  (0.60)   Depth: 3   00:00:00
1...a6 2.a4 Bc7 3.Re2 Rd1
  ²  (0.58)   Depth: 3   00:00:00
  ²  (0.53)   Depth: 9   00:00:00  13kN
1...Bxf4 2.gxf4 Rd2+ 3.Kb1 g3 4.Re1 Kxf4 5.Ne7 Kg4 6.Ng8 Rf2 7.R8e6 Kxh4 8.Nxf6
Rf7
  ²  (0.33)   Depth: 9   00:00:00  44kN
  =  (-0.02)   Depth: 15   00:01:01  8139kN

Junior7  is not known as a program that overestimate passed pawn
and I have a position in my correspondence game when I have 3 passed pawns for a
piece
and Junior7 is relatively not optimistic(it says similiar scores to Crafty of
equality when Deep Fritz says 1 pawn advantage for me)

I think that the important point here is the fact that the passed pawns are
supported by the king.

You can look at the game shredder-Junior from the last WMCCC when shredder
evaluated it's position as +5 and lost the game.

If your program also evaluates the positions from this game as more than +5 then
your program is too optimistic about passed pawns.

Here is one of the relevant positions with some small analysis of
shredder5.32(p200)



Deep Junior 7 - Shredder
[D]1r5k/7p/2q2P2/6P1/p2p1N1K/2b1pBP1/8/3Q4 b - - 0 1

Analysis by Shredder 5.32:

63...d3 64.Bxc6
  +-  (2.89)   Depth: 1/2   00:00:00
  +-  (5.25)   Depth: 1/2   00:00:00
63...Qd7 64.Bd5 Re8
  -+  (-4.41)   Depth: 1/2   00:00:00
  -+  (-5.79)   Depth: 3/6   00:00:00
63...Qb5 64.Bd5 Re8
  -+  (-5.80)   Depth: 3/6   00:00:00
  -+  (-6.00)   Depth: 3/6   00:00:00
63...Qa6 64.Be2 Qa7 65.Kg4
  -+  (-6.03)   Depth: 3/6   00:00:00
  -+  (-6.28)   Depth: 4/8   00:00:00
63...Qd7 64.Bd5 a3 65.g4 Re8 66.Kg3
  -+  (-6.29)   Depth: 4/8   00:00:00
  -+  (-6.01)   Depth: 6/12   00:00:01  23kN
63...Qa6 64.Bd5 Rb2 65.Kg4 a3 66.Ne6
  -+  (-6.02)   Depth: 6/12   00:00:01  27kN
  -+  (-6.13)   Depth: 6/12   00:00:02  39kN
63...Qe8 64.Bd5 a3 65.Qf1 Qe5 66.Qa6 Bb2
  -+  (-6.14)   Depth: 6/12   00:00:02  53kN
  -+  (-5.92)   Depth: 7/14   00:00:03  84kN


Uri



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