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Subject: Re: Why can't Shredder 7 solve this simple endgame position?

Author: Mike S.

Date: 18:05:11 04/03/03

Go up one level in this thread


On April 03, 2003 at 07:56:04, Jouni Uski wrote:

>[D]8/8/8/5bk1/8/8/4B1PP/5K2 b - -
>S7 don't find -Bh3 in 10 minutes. Why???? I don't have full 5 piece TBs for
>sure, but most amateurs find move even without (any) TBs.

Shredder 7.SE (in-between version between 7/7.04) also doesn's seem to find
Bh5(Lh5), when all pieces are moved 2 ranks upwards:

[D]8/5bk1/8/8/4B1PP/5K2/8/8 b - - 0 1

Neue Partie
8/5bk1/8/8/4B1PP/5K2/8/8 b - - 0 1

Analysis by Shredder 7.SE:

1...Kh6 2.Lh7 Kxh7 3.Kf4
  +-  (2.92)   Tiefe: 1/2   00:00:00
  +-  (3.21)   Tiefe: 9/13   00:00:01  57kN, tb=861
1...Le8 2.g5 Lf7 3.Kg4 Le6+ 4.Kf3 Lc4
  +-  (3.20)   Tiefe: 9/13   00:00:01  72kN, tb=1096
  +-  (3.28)   Tiefe: 10/15   00:00:02  150kN, tb=1833

(...)

1...Le8 2.g5 Lh5+ 3.Kf4 Le8 4.Lf3 Ld7
  +-  (4.22)   Tiefe: 19/27   00:00:46  10735kN, tb=81107
  +-  (4.26)   Tiefe: 20/25   00:00:54  12967kN, tb=99021
1...Kh6 2.Kg3 Kg7 3.Kf4 Le8 4.Lf3 Lb5 5.g5 Le8
  +-  (4.25)   Tiefe: 20/25   00:01:02  15395kN, tb=121359
  +-  (4.33)   Tiefe: 21/28   00:02:13  36897kN, tb=252318

Btw. an older Shredder version 5.32 immediatly decided to play Bh3/Bh5 in these
positions. People having no. 6 versions may want to check for that too.

Neue Partie
8/5bk1/8/8/4B1PP/5K2/8/8 b - - 0 1

Analysis by Shredder 5.32:

1...Kh6 2.Kf4
  +-  (2.96)   Depth: 1/2   00:00:00
  +-  (2.96)   Depth: 2/4   00:00:00

(...)

1...Bh5 2.Bd3 Bxg4+ 3.Kxg4
  +-  (2.87)   Depth: 5/10   00:00:00
  =  (0.01)   Depth: 26/38   00:00:10  2997kN, tb=47382

and (in the original test position):

New game
8/8/8/5bk1/8/8/4B1PP/5K2 b - - 0 1

Analysis by Shredder 5.32:

1...Be4 2.Bf3
  +-  (1.82)   Depth: 1/2   00:00:00
  +-  (1.83)   Depth: 2/4   00:00:00

(...)

1...Bh3 2.Bd3 Bxg2+ 3.Kf2 Kh4 4.Kxg2
  +-  (1.95)   Depth: 8/16   00:00:00  21kN, tb=497
  =  (0.01)   Depth: 26/38   00:00:11  2548kN, tb=86757

I'm afraid this could be a bug in Shredder 7's usage of the wrong colored bishop
motif, because after Bh3, it sees quickly that it is a draw. It just doesn't
seem to be able to play Bh3 previously.

Although, maybe (?) other moves for black may hold the draw too - I'm not sure
at the moment - in which case it wouldn't be a big accident. But I'd prefer it
plays Bh3 with the "crystal clear" draw, like it's predecessor Shredder 5.32.

The main question would be, if similar draws are missed for that reason.

Regards,
M.Scheidl



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