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Subject: Re: Bookup's backsolving PV Evals

Author: chandler yergin

Date: 02:09:27 05/18/05

Go up one level in this thread


On May 17, 2005 at 14:29:19, Robin Smith wrote:

>On May 13, 2005 at 23:49:26, Komputer Korner wrote:
>
>"Komputer Korner",
>
>Your post is full of errors. See below for a point by point rebuttal.
>
>>On May 12, 2005 at 18:31:52, Dann Corbit wrote:
>>
>>>Bookups backsolving is basically a minimax algorithm + refutations.
>>>
>>>ChessAssistant does the same thing.
>>>
>>>It is a very good idea.
>>>
>>>IMO-YMMV.
>>The following explanation will prove that I am the real KK. Compare my answer
>>with logical opening theory articles and the 10 kommandments I did 5 years ago.
>>The problem is that minimax is only useful to a computer.
>
>Wrong. Minimax is useful to anyone doing tree searching. Chess masters use
>minimax all the time; they just don't call it that. Instead they say things like
>"16.Re1 initially looked appealing, but then I saw the killer reply Bxh7+". In
>essense this is a verbal description of either the masters thinking or the
>minimax algorithm.
>
>>We humans have brains.
>
>Some of us do. :-)
>
>>All one has to do is put a chess engine to work at any node to get an
>>evaluation. Usually the evaluation will be less than a pawn. If it is more than
>>a pawn, then 99.9% of the time the line is busted for one of the sides.
>
>I am sure the number is far lower. Just play through some GM games. Many times
>the evaluation will go above a pawn, even though the position is still drawn.
>This is especially true in the endgame, but can occur at any phase. Chess
>engines are not oracles.
>
>>If it is
>>less than a pawn, then the decision for the White side is how much of a pawn
>>advantage do you need before continuing with the line? The opening advantage is
>>about .13 of a pawn.
>
>The precision of your proclomation is absurd. Are you sure it isn't .14 pawns?
>Or how about .20 pawns? I have seen claims as high as .33 pawns.

Here's a good example of a high Eval; but the popsition is a Draw.

I think Robin would agree?

[D]8/2p5/2B2k2/p4bp1/3P4/6K1/1P6/8 w - - 0 1



Analysis by Shredder 8:

1.Kf3
  -+  (-1.63)   Depth: 1/1   00:00:00
1.Kf3 Ke6 2.Bb7 Kd6 3.b3
  -+  (-1.85)   Depth: 5/8   00:00:00
1.Kf3 Ke6 2.Bb7 Kd6 3.b3
  -+  (-1.85)   Depth: 5/8   00:00:00
1.Kf3 Ke6 2.Bb7 Kd6 3.b3
  -+  (-1.85)   Depth: 5/8   00:00:00
1.Kf3 Ke6 2.Bb7 Kd6 3.b3
  -+  (-1.85)   Depth: 5/8   00:00:00
1.Kf3 Ke6 2.Bb7 Kd6
  -+  (-1.71)   Depth: 6/8   00:00:00
1.Kf3 Ke6 2.Bb7 Kd6
  -+  (-1.71)   Depth: 6/8   00:00:00
1.Kf3 Ke6 2.Bb7 Kd6
  -+  (-1.71)   Depth: 6/8   00:00:00
1.Kf3 Ke6 2.Bb7 Kd6
  -+  (-1.71)   Depth: 6/8   00:00:00
1.Kf3 Ke6 2.Ke3
  -+  (-1.71)   Depth: 6/8   00:00:00
1.Kf3 Ke6 2.Ke3 Kd6 3.Bb7 Be6 4.Kf3
  -+  (-1.85)   Depth: 7/10   00:00:00  7kN, tb=3
1.Bb7 Be6
  -+  (-1.84)   Depth: 7/10   00:00:00  8kN, tb=3
1.Bb7 Be6 2.Kf3 Bc4 3.Be4 Ke6 4.Bb7
  -+  (-1.73)   Depth: 7/11   00:00:00  9kN, tb=3
1.Bb7 Ke7 2.Kf3 Kd6 3.Ke3 Be6 4.Kf2 g4
  -+  (-1.89)   Depth: 8/10   00:00:00  18kN, tb=5
1.Kf3 Ke6 2.d5+ Ke5 3.Bb7
  -+  (-1.88)   Depth: 8/11   00:00:00  19kN, tb=5
1.Kf3 Ke6 2.d5+ Ke5 3.Bb7
  -+  (-1.88)   Depth: 8/11   00:00:00  19kN, tb=5
1.Bd5 Bd3 2.Bc6 Be2
  -+  (-1.87)   Depth: 8/13   00:00:00  23kN, tb=6
1.Bd5 Ke7 2.Bg8 Kd6 3.Kf3
  -+  (-1.87)   Depth: 8/13   00:00:01  30kN, tb=8
1.Bd5 Ke7 2.Bb7 Be6 3.d5 Bf5 4.Kf3 Kd6 5.b3
  -+  (-1.92)   Depth: 9/15   00:00:02  39kN, tb=30
1.Bb7 Ke7
  -+  (-1.91)   Depth: 9/15   00:00:02  40kN, tb=30
1.Bb7 Ke7 2.Kf3 Kd6 3.Ba8
  -+  (-1.89)   Depth: 9/15   00:00:02  41kN, tb=30
1.Bb7 Ke7 2.Bg2 Kd6 3.Kf2 g4 4.Bc6
  -+  (-1.94)   Depth: 10/14   00:00:02  59kN, tb=34
1.Kf2 Ke6 2.Bf3 Kd6
  -+  (-1.93)   Depth: 10/14   00:00:02  69kN, tb=34
1.Kf2 Ke6 2.Ba4
  -+  (-1.93)   Depth: 10/14   00:00:02  70kN, tb=34
1.Kf2 Ke7 2.Kg3 Kd6 3.Bg2 Bd7 4.Bf3 Bc6 5.Be2 Be4 6.Kg4
  -+  (-1.98)   Depth: 11/15   00:00:03  96kN, tb=37
1.Bb7 Ke7
  -+  (-1.97)   Depth: 11/15   00:00:03  98kN, tb=37
1.Bb7 Ke7 2.Kf3 Kd6 3.d5
  -+  (-1.97)   Depth: 11/15   00:00:03  99kN, tb=37
1.Bb7 Ke7 2.Bh1 Kd6 3.Kf3 Be6 4.Kg2
  -+  (-2.01)   Depth: 12/16   00:00:03  133kN, tb=37
1.Bb7 Ke7 2.Bh1 Kd6 3.Kf2 c6 4.Bg2 c5 5.dxc5+ Kxc5 6.Kg3
  -+  (-2.02)   Depth: 13/17   00:00:05  186kN, tb=66
1.Bb7 Ke7 2.Kf3 Kd6 3.Ke3 Be6 4.Be4 c5 5.Bg2 Bd5 6.dxc5+ Kxc5 7.Bh3 Kc4 8.Bf5
  -+  (-2.02)   Depth: 14/19   00:00:09  304kN, tb=214
1.Bb7 Ke7 2.Kf3 Kd6 3.Ke3 c6 4.Ba6 Kd5 5.Be2 c5 6.Bf3+ Kc4 7.dxc5 Kxc5 8.b3 g4
9.Bb7
  -+  (-2.05)   Depth: 15/20   00:00:12  394kN, tb=294
1.Bb7 Ke7 2.Kf3 Kd6 3.Ke3 c6 4.Ba6 Kd5 5.Be2 c5 6.Bf3+ Kc4 7.Be2+ Kb4 8.dxc5
Kxc5 9.Bf1
  -+  (-2.05)   Depth: 16/20   00:00:16  485kN, tb=424
1.Bb7 Ke7 2.Kf3 Kd6 3.Ke3 c6 4.Ba6 Kd5 5.Bf1 c5 6.Bg2+ Kc4 7.Kf2
  -+  (-2.05)   Depth: 17/22   00:00:17  610kN, tb=537
1.Bb7 Ke7 2.Kf3 Kd6 3.Ke3 c6 4.Ba6 Kd5 5.Bf1 c5 6.Bg2+ Kc4 7.Bf1+ Kb4
  -+  (-2.05)   Depth: 18/23   00:00:19  745kN, tb=737
1.Bf3 Ke6 2.Kf2 Kd6 3.Ke3 g4 4.Bg2 Ke6
  -+  (-2.04)   Depth: 18/27   00:00:26  1316kN, tb=2041
1.Bf3 Ke6 2.Kf2 Kd6 3.Ke3 Be6 4.Bg2 Bd5 5.Bh3 Bf7 6.Kf2 Kd5 7.Ke3 Be6 8.Kf2
  -+  (-2.04)   Depth: 18/27   00:00:26  1374kN, tb=2191
1.Bf3 Ke6 2.Kf2 Kd6 3.Ke3 Be6 4.Bg2 Bd5 5.Bh3 Bf7 6.Bg2 Be6 7.Be4
  -+  (-2.04)   Depth: 19/23   00:00:28  1709kN, tb=2918
1.Bf3 Ke6 2.Kf2 Kd6 3.Ke3 Be6 4.Bg2 Bd5 5.Bh3 Bf7 6.Bg2 Be6 7.Be4
  -+  (-2.04)   Depth: 20/21   00:00:32  2154kN, tb=3798
1.Bf3 Ke6 2.Kf2 Kd6 3.Ke3 c5 4.dxc5+ Kxc5 5.Bd1 g4 6.Kf2 Be6 7.Kg3 Bd7
  -+  (-2.05)   Depth: 21/25   00:00:46  3829kN, tb=6642
1.Bf3 Ke6 2.Kf2 Kd6 3.Ke3 Be6 4.Bg2 c5 5.dxc5+ Kxc5 6.Be4 Kc4 7.Bc2 Bd5 8.Bd1
Bc6 9.Bc2 g4 10.Kf2 Bd5
  -+  (-2.11)   Depth: 22/27   00:01:01  5761kN, tb=11331
1.Kf2 Ke7 2.Ke3 Kd6 3.Ba4 Kd5 4.Bb3+ Kd6
  -+  (-2.10)   Depth: 22/27   00:01:13  8368kN, tb=14629
1.Kf2 Ke7 2.Ke3 Kd6 3.Ba4 Kd5 4.Bb3+ Kc6 5.Ba4+ Kd6 6.Bb3 g4
  -+  (-2.07)   Depth: 22/27   00:01:17  9523kN, tb=15214
1.Kf2 Ke6 2.Ke3 Bc2 3.Bh1 Kd6 4.Bg2 Bf5 5.Bb7
  -+  (-2.11)   Depth: 23/32   00:01:40  14597kN, tb=22579
1.Ba4 Ke6 2.Bb3+ Kd6 3.Kf3 Be6 4.Bc2 g4+ 5.Kf4 c5 6.dxc5+ Kc6
  -+  (-2.10)   Depth: 23/36   00:01:55  16809kN, tb=26887
1.Ba4 Ke6 2.Bb3+ Kd6 3.Kf3 Bd7 4.Ke3 Bc6 5.Bc2 Ke6 6.Bb3+ Bd5 7.Bc2 Kd6
  -+  (-2.04)   Depth: 23/36   00:02:05  20186kN, tb=28735
1.Ba4 Ke6 2.Bb3+ Kd6 3.Kf3 Bd7 4.Ke3 Bc6 5.Bc2 Ke6 6.Bb3+ Bd5 7.Bc2 Kd6 8.Bd3 c5
9.dxc5+ Kxc5 10.Bf5
  -+  (-2.04)   Depth: 24/29   00:02:25  22732kN, tb=34910
1.Ba4 Ke6 2.Bb3+ Kd6 3.Kf3 Bd7 4.Ke3 Be6 5.Bc2 c5 6.dxc5+ Kxc5
  -+  (-2.06)   Depth: 25/45   00:03:38  29362kN, tb=52260
1.Ba4 Ke6 2.Bb3+ Kd6 3.Kf3 Bd7 4.Ke3 Be6 5.Bc2 c5 6.dxc5+ Kxc5 7.Kf2 Kc4 8.Kf3
Kd5 9.Ke3 Ke5 10.Kf3 Kd4 11.Ba4 Bf5
  -+  (-2.08)   Depth: 26/47   00:05:31  37151kN, tb=76634
1.Ba4 Ke6 2.Bb3+ Kd6 3.Kf3 Bd7 4.Ke3 Be6 5.Bc2 c5 6.dxc5+ Kxc5 7.Kf2 Kc4 8.Kf3
Kb4 9.Kf2 Bb3 10.Be4 Kc5
  -+  (-2.08)   Depth: 27/51   00:09:50  55810kN, tb=132033

(,  18.05.2005)

PLaying the Best move 1.Ba4 we get this position:

[D]8/2p5/5k2/p4bp1/B2P4/6K1/1P6/8 b - - 0 1


Analysis by Shredder 8:

1...c5 2.dxc5 Be4 3.Kf2 Ke6 4.Bb3+ Kf5 5.Kg3 Ke5
  ³  (-0.26)   Depth: 1/2   00:00:00
1...Ke6 2.Bb3+ Kd6 3.Kf3 Bc8 4.Kf2 Be6 5.Bc2 Bd7 6.Ke3 g4 7.Bb3 Be6 8.Ba4 Bd5
9.Kf4 c5
  -+  (-2.08)   Depth: 10/10   00:00:00
1...Ke6 2.Bb3+ Kd6 3.Kf3 Bc8 4.Kf2 Be6 5.Bc2 Bd7 6.Ke3 g4 7.Bb3 Be6 8.Ba4 Bd5
9.Kf4 c5
  -+  (-2.08)   Depth: 10/10   00:00:00
1...Ke6 2.Bb3+ Kd6 3.Kf3 Bc8 4.Kf2 Be6 5.Bc2 Bd7 6.Ke3 g4 7.Bb3 Be6 8.Ba4 Bd5
9.Kf4 c5
  -+  (-2.08)   Depth: 10/10   00:00:00
1...Ke6 2.Bb3+ Kd6 3.Kf3 Bc8 4.Kf2 Be6 5.Bc2 Bd7 6.Ke3 g4 7.Bb3 Be6 8.Ba4 Bd5
9.Kf4 c5
  -+  (-2.08)   Depth: 10/10   00:00:00
1...Ke6 2.Bb3+ Kd6 3.Kf3 Bc8 4.Kf2 Be6 5.Bc2 Bd7 6.Ke3 g4 7.Bb3 Be6 8.Ba4 Bd5
9.Kf4 c5
  -+  (-2.08)   Depth: 10/10   00:00:00
1...Ke6 2.Bb3+ Kd6 3.Kf3 Bc8 4.Kf2 Be6 5.Bc2 Bd7 6.Ke3 g4 7.Bb3 Be6 8.Ba4 Bd5
9.Kf4 c5
  -+  (-2.08)   Depth: 10/10   00:00:00
1...Ke6 2.Bb3+ Kd6 3.Kf3 Bc8 4.Kf2 Be6 5.Bc2 Bd7 6.Ke3 g4 7.Bb3 Be6 8.Ba4 Bd5
9.Kf4 c5
  -+  (-2.08)   Depth: 10/10   00:00:00
1...Ke6 2.Bb3+ Kd6 3.Kf3 Bc8 4.Kf2 Be6 5.Bc2 Bd7 6.Ke3 g4 7.Bb3 Be6 8.Ba4 Bd5
9.Kf4 c5
  -+  (-2.08)   Depth: 10/10   00:00:00
1...Ke6 2.Bb3+ Kd6 3.Kf3 Bc8 4.Kf2 Be6 5.Bc2 Bd7 6.Ke3 g4 7.Bb3 Be6 8.Ba4 Bd5
9.Kf4 c5
  -+  (-2.08)   Depth: 10/10   00:00:00
1...Ke6 2.Bb3+ Kd6 3.Kf3 Bc8 4.Kf2 Be6 5.Bc2 Bd7 6.Ke3 g4 7.Bb3 Be6 8.Ba4 Bd5
9.Kf4 c5
  -+  (-2.08)   Depth: 10/10   00:00:00
1...Ke6 2.Bb3+ Kd6 3.Kf3 Bc8 4.Kf2 Be6 5.Bc2 Bd7 6.Ke3 g4 7.Bb3 Be6 8.Ba4 Bd5
9.Kf4 c5
  -+  (-2.08)   Depth: 10/10   00:00:00
1...Ke6 2.Bb3+ Kd6 3.Kf3 Bc8 4.Kf2 Be6 5.Bc2 Bd7 6.Ke3 g4 7.Bb3 Be6 8.Ba4 Bd5
9.Kf4 c5
  -+  (-2.08)   Depth: 10/10   00:00:00
1...Ke6 2.Bb3+ Kd6 3.Kf3 Bc8 4.Kf2 Be6 5.Bc2 Bd7 6.Ke3 g4 7.Bb3 Be6 8.Ba4 Bd5
9.Kf4 c5
  -+  (-2.08)   Depth: 11/11   00:00:00
1...Ke6 2.Bb3+ Kd6 3.Kf3 Bc8 4.Kf2 Be6 5.Bc2 Bd7 6.Ke3 g4 7.Bb3 Be6 8.Ba4 Bd5
9.Kf4 c5
  -+  (-2.08)   Depth: 12/12   00:00:00
1...Ke6 2.Bb3+ Kd6 3.Kf3 Bc8 4.Kf2 Be6 5.Bc2 Bd7 6.Ke3 g4 7.Bb3 Be6 8.Ba4 Bd5
9.Kf4 c5
  -+  (-2.08)   Depth: 15/15   00:00:00
1...Ke6 2.Bb3+ Kd6 3.Kf3 Bc8 4.Kf2 Be6 5.Bc2 Bd7 6.Ke3 g4 7.Bb3 Be6 8.Ba4 Bd5
9.Kf4 c5
  -+  (-2.08)   Depth: 15/15   00:00:00
1...Ke6 2.Bb3+ Kd6 3.Kf3 Bc8 4.Kf2 Be6 5.Bc2 Bd7 6.Ke3 g4 7.Bb3 Be6 8.Ba4 Bd5
9.Kf4 c5
  -+  (-2.08)   Depth: 15/15   00:00:00
1...Ke6 2.Bb3+ Kd6 3.Kf3 Bc8 4.Kf2 Be6 5.Bc2 Bd7 6.Ke3 g4 7.Bb3 Be6 8.Ba4 Bd5
9.Kf4 c5
  -+  (-2.08)   Depth: 16/16   00:00:00
1...Ke6 2.Bb3+ Kd6 3.Kf3 Bc8 4.Kf2 Be6 5.Bc2 Bd7 6.Ke3 g4 7.Bb3 Be6 8.Ba4 Bd5
9.Kf4 c5
  -+  (-2.08)   Depth: 17/17   00:00:00
1...Ke6 2.Bb3+ Kd6 3.Kf3 Bc8 4.Kf2 Be6 5.Bc2 Bd7 6.Ke3 g4 7.Bb3 Be6 8.Ba4 Bd5
9.Kf4 c5
  -+  (-2.08)   Depth: 18/18   00:00:01
1...Ke6 2.Bb3+ Kd6 3.Kf3 Bc8 4.Kf2 Be6 5.Bc2 Bd7 6.Ke3 g4 7.Bb3 Be6 8.Ba4 Bd5
9.Kf4 c5
  -+  (-2.08)   Depth: 19/19   00:00:01
1...Ke6 2.Bb3+ Kd6 3.Kf3 Bc8 4.Kf2 Be6 5.Bc2 Bd7 6.Ke3 g4 7.Bb3 Be6 8.Ba4 Bd5
9.Kf4 c5
  -+  (-2.08)   Depth: 20/20   00:00:03
1...Ke6 2.Bb3+ Kd6 3.Kf3 Bc8 4.Kf2 Be6 5.Bc2 Bd7 6.Ke3 g4 7.Bb3 Be6 8.Ba4 Bd5
9.Kf4 c5
  -+  (-2.08)   Depth: 21/21   00:00:05
1...Ke6 2.Bb3+ Kd6 3.Kf3 Bc8 4.Kf2 Be6 5.Bc2 Bd7 6.Ke3 g4 7.Bb3 Be6 8.Ba4 Bd5
9.Kf4 c5
  -+  (-2.08)   Depth: 22/22   00:00:07  1kN
1...Ke6 2.Bb3+ Kd6 3.Kf3 Bc8 4.Kf2 Be6 5.Bc2 Bd7 6.Ke3 g4 7.Bb3 Be6 8.Ba4 Bd5
9.Kf4 c5
  -+  (-2.08)   Depth: 23/23   00:00:09  2kN
1...Ke6 2.Bb3+ Kd6 3.Kf3 Bc8 4.Kf2 Be6 5.Bc2 Bd7 6.Ke3 g4 7.Bb3 Be6 8.Ba4 Bd5
9.Kf4 c5
  -+  (-2.08)   Depth: 24/24   00:00:11  3kN
1...Ke6 2.Bb3+ Kd6 3.Kf3 Bc8 4.Kf2 Be6 5.Bc2 Bd7 6.Ke3 g4 7.Bb3 Be6 8.Ba4 Bd5
9.Kf4 c5
  -+  (-2.08)   Depth: 25/25   00:00:11  12kN, tb=3
1...Ke6 2.Bb3+ Kd6 3.Kf3 Bc8 4.Kf2 Be6 5.Bc2 Bd7 6.Ke3 g4 7.Bb3 Be6 8.Ba4 Bd5
9.Kf4 c5
  -+  (-2.08)   Depth: 26/26   00:00:11  21kN, tb=6
1...Ke6 2.Bb3+ Kd7 3.Kf3 Kc6 4.Bc4 Bc8 5.Kf2 Kd6 6.Ke3 c5 7.dxc5+ Kd7
  -+  (-2.08)   Depth: 27/41   00:03:10  15345kN, tb=31979

(,  18.05.2005)

Playing a few more moves of the best Line..

[D]2b5/2p5/2k5/p5p1/2BP4/4K3/1P6/8 b - - 0 5


Analysis by Shredder 8:

5...g4 6.Bb3 Be6 7.Bxe6 g3 8.Kf3 Kb5
  -+  (-2.06)   Depth: 1/1   00:00:00
5...Bf5 6.Kf3 Bc8 7.Kf2 Kd6 8.Bb3 Kc6 9.Bc4 Kd6 10.Bb3 Kc6 11.Bc4 Kd6
  -+  (-2.08)   Depth: 17/17   00:00:00
5...Bf5 6.Kf3 Bc8 7.Kf2 Kd6 8.Bb3 Kc6 9.Bc4 Kd6 10.Bb3 Kc6 11.Bc4 Kd6
  -+  (-2.08)   Depth: 17/17   00:00:00
5...Bf5 6.Kf3 Bc8 7.Kf2 Kd6 8.Bb3 Kc6 9.Bc4 Kd6 10.Bb3 Kc6 11.Bc4 Kd6
  -+  (-2.08)   Depth: 17/17   00:00:00
5...Bf5 6.Kf3 Bc8 7.Kf2 Kd6 8.Bb3 Kc6 9.Bc4 Kd6 10.Bb3 Kc6 11.Bc4 Kd6
  -+  (-2.08)   Depth: 17/17   00:00:00
5...Bf5 6.Kf3 Bc8 7.Kf2 Kd6 8.Bb3 Kc6 9.Bc4 Kd6 10.Bb3 Kc6 11.Bc4 Kd6
  -+  (-2.08)   Depth: 17/17   00:00:00
5...Bf5 6.Kf3 Bc8 7.Kf2 Kd6 8.Bb3 Kc6 9.Bc4 Kd6 10.Bb3 Kc6 11.Bc4 Kd6
  -+  (-2.08)   Depth: 17/17   00:00:00
5...Bf5 6.Kf3 Bc8 7.Kf2 Kd6 8.Bb3 Kc6 9.Bc4 Kd6 10.Bb3 Kc6 11.Bc4 Kd6
  -+  (-2.08)   Depth: 17/17   00:00:00
5...Bf5 6.Kf3 Bc8 7.Kf2 Kd6 8.Bb3 Kc6 9.Bc4 Kd6 10.Bb3 Kc6 11.Bc4 Kd6
  -+  (-2.08)   Depth: 17/17   00:00:00
5...Bf5 6.Kf3 Bc8 7.Kf2 Kd6 8.Bb3 Kc6 9.Bc4 Kd6 10.Bb3 Kc6 11.Bc4 Kd6
  -+  (-2.08)   Depth: 17/17   00:00:00
5...Bf5 6.Kf3 Bc8 7.Kf2 Kd6 8.Bb3 Kc6 9.Bc4 Kd6 10.Bb3 Kc6 11.Bc4 Kd6
  -+  (-2.08)   Depth: 17/17   00:00:00
5...Bf5 6.Kf3 Bc8 7.Kf2 Kd6 8.Bb3 Kc6 9.Bc4 Kd6 10.Bb3 Kc6 11.Bc4 Kd6
  -+  (-2.08)   Depth: 17/17   00:00:00
5...Bf5 6.Kf3 Bc8 7.Kf2 Kd6 8.Bb3 Kc6 9.Bc4 Kd6 10.Bb3 Kc6 11.Bc4 Kd6
  -+  (-2.08)   Depth: 17/17   00:00:00
5...Bf5 6.Kf3 Bc8 7.Kf2 Kd6 8.Bb3 Kc6 9.Bc4 Kd6 10.Bb3 Kc6 11.Bc4 Kd6
  -+  (-2.08)   Depth: 17/17   00:00:00
5...Bf5 6.Kf3 Bc8 7.Kf2 Kd6 8.Bb3 Kc6 9.Bc4 Kd6 10.Bb3 Kc6 11.Bc4 Kd6
  -+  (-2.08)   Depth: 17/17   00:00:00
5...Bf5 6.Kf3 Bc8 7.Kf2 Kd6 8.Bb3 Kc6 9.Bc4 Kd6 10.Bb3 Kc6 11.Bc4 Kd6
  -+  (-2.08)   Depth: 17/17   00:00:00
5...Bf5 6.Kf3 Bc8 7.Kf2 Kd6 8.Bb3 Kc6 9.Bc4 Kd6 10.Bb3 Kc6 11.Bc4 Kd6
  -+  (-2.08)   Depth: 17/17   00:00:00
5...Bf5 6.Kf3 Bc8 7.Kf2 Kd6 8.Bb3 Kc6 9.Bc4 Kd6 10.Bb3 Kc6 11.Bc4 Kd6
  -+  (-2.08)   Depth: 17/17   00:00:00
5...Bf5 6.Kf3 Bc8 7.Kf2 Kd6 8.Bb3 Kc6 9.Bc4 Kd6 10.Bb3 Kc6 11.Bc4 Kd6
  -+  (-2.08)   Depth: 17/17   00:00:00
5...Bf5 6.Kf3 Bc8 7.Kf2 Kd6 8.Bb3 Kc6 9.Bc4 Kd6 10.Bb3 Kc6 11.Bc4 Kd6
  -+  (-2.08)   Depth: 17/17   00:00:00
5...Bf5 6.Kf3 Bc8 7.Kf2 Kd6 8.Bb3 Kc6 9.Bc4 Kd6 10.Bb3 Kc6 11.Bc4 Kd6
  -+  (-2.08)   Depth: 17/17   00:00:00
5...Bf5 6.Kf3 Bc8 7.Kf2 Kd6 8.Bb3 Kc6 9.Bc4 Kd6 10.Bb3 Kc6 11.Bc4 Kd6
  -+  (-2.08)   Depth: 17/17   00:00:00
5...Bf5 6.Kf3 Bc8 7.Kf2 Kd6 8.Bb3 Kc6 9.Bc4 Kd6 10.Bb3 Kc6 11.Bc4 Kd6
  -+  (-2.08)   Depth: 18/18   00:00:00  3kN
5...Bf5 6.Kf3 Bc8 7.Kf2 Kd6 8.Bb3 Kc6 9.Bc4 Kd6 10.Bb3 Kc6 11.Bc4 Kd6
  -+  (-2.08)   Depth: 19/19   00:00:00  20kN, tb=21
5...Bf5 6.Kf3 Bc8 7.Kf2 Kd6 8.Bb3 Kc6 9.Bc4 Kd6 10.Bb3 Kc6 11.Bc4 Kd6
  -+  (-2.08)   Depth: 20/24   00:00:06  373kN, tb=430
5...Bf5 6.Kf3 Bc8 7.Kf2 Kd6 8.Bb3 Kc6 9.Bc4 Kd6 10.Bb3 Kc6 11.Bc4 Kd6
  -+  (-2.08)   Depth: 21/26   00:00:21  990kN, tb=1956
5...Bf5 6.Kf3 Bc8 7.Kf2 Kd6 8.Bb3 Kc6 9.Bc4 Kd6 10.Bb3 Kc6 11.Bc4 Kd6
  -+  (-2.08)   Depth: 22/31   00:00:40  1818kN, tb=4590
5...Bf5 6.Kf3 Bc8 7.Kf2 Kd6 8.Bb3 Kc6 9.Bc4 Kd6 10.Bb3 Kc6 11.Bc4 Kd6
  -+  (-2.08)   Depth: 23/31   00:01:06  2892kN, tb=7525
5...Bf5 6.Kf3 Bc8
  -+  (-2.08)   Depth: 24/36   00:01:49  4950kN, tb=14050
5...Bf5 6.Kf3 Bh3 7.Kg3 Bd7 8.Kf3 Kd6 9.Bb3 Bh3 10.Kg3 Be6 11.Bc2 g4
  -+  (-2.08)   Depth: 25/38   00:05:18  27206kN, tb=53194

(,  18.05.2005)


It's easy to see the PV Eval is based on static positional factors
Programmed in.

Does this high Eval mean Black has a Won Game?

Certainly not.

It's a Draw.

New game,
2b5/2p5/2k5/p5p1/2BP4/4K3/1P6/8 b - - 0 1

Analysis by Shredder 8:

5...g4 6.Bb3 Be6 7.Bxe6 g3 8.Kf3 Kb5
  -+  (-2.06)   Depth: 1/1   00:00:00
5...Bf5 6.Kf3 Bc8 7.Kf2 Kd6 8.Bb3 Kc6 9.Bc4 Kd6 10.Bb3 Kc6 11.Bc4 Kd6
  -+  (-2.08)   Depth: 17/17   00:00:00
5...Bf5 6.Kf3 Bc8 7.Kf2 Kd6 8.Bb3 Kc6 9.Bc4 Kd6 10.Bb3 Kc6 11.Bc4 Kd6
  -+  (-2.08)   Depth: 17/17   00:00:00
5...Bf5 6.Kf3 Bc8 7.Kf2 Kd6 8.Bb3 Kc6 9.Bc4 Kd6 10.Bb3 Kc6 11.Bc4 Kd6
  -+  (-2.08)   Depth: 17/17   00:00:00
5...Bf5 6.Kf3 Bc8 7.Kf2 Kd6 8.Bb3 Kc6 9.Bc4 Kd6 10.Bb3 Kc6 11.Bc4 Kd6
  -+  (-2.08)   Depth: 17/17   00:00:00
5...Bf5 6.Kf3 Bc8 7.Kf2 Kd6 8.Bb3 Kc6 9.Bc4 Kd6 10.Bb3 Kc6 11.Bc4 Kd6
  -+  (-2.08)   Depth: 17/17   00:00:00
5...Bf5 6.Kf3 Bc8 7.Kf2 Kd6 8.Bb3 Kc6 9.Bc4 Kd6 10.Bb3 Kc6 11.Bc4 Kd6
  -+  (-2.08)   Depth: 17/17   00:00:00
5...Bf5 6.Kf3 Bc8 7.Kf2 Kd6 8.Bb3 Kc6 9.Bc4 Kd6 10.Bb3 Kc6 11.Bc4 Kd6
  -+  (-2.08)   Depth: 17/17   00:00:00
5...Bf5 6.Kf3 Bc8 7.Kf2 Kd6 8.Bb3 Kc6 9.Bc4 Kd6 10.Bb3 Kc6 11.Bc4 Kd6
  -+  (-2.08)   Depth: 17/17   00:00:00
5...Bf5 6.Kf3 Bc8 7.Kf2 Kd6 8.Bb3 Kc6 9.Bc4 Kd6 10.Bb3 Kc6 11.Bc4 Kd6
  -+  (-2.08)   Depth: 17/17   00:00:00
5...Bf5 6.Kf3 Bc8 7.Kf2 Kd6 8.Bb3 Kc6 9.Bc4 Kd6 10.Bb3 Kc6 11.Bc4 Kd6
  -+  (-2.08)   Depth: 17/17   00:00:00
5...Bf5 6.Kf3 Bc8 7.Kf2 Kd6 8.Bb3 Kc6 9.Bc4 Kd6 10.Bb3 Kc6 11.Bc4 Kd6
  -+  (-2.08)   Depth: 17/17   00:00:00
5...Bf5 6.Kf3 Bc8 7.Kf2 Kd6 8.Bb3 Kc6 9.Bc4 Kd6 10.Bb3 Kc6 11.Bc4 Kd6
  -+  (-2.08)   Depth: 17/17   00:00:00
5...Bf5 6.Kf3 Bc8 7.Kf2 Kd6 8.Bb3 Kc6 9.Bc4 Kd6 10.Bb3 Kc6 11.Bc4 Kd6
  -+  (-2.08)   Depth: 17/17   00:00:00
5...Bf5 6.Kf3 Bc8 7.Kf2 Kd6 8.Bb3 Kc6 9.Bc4 Kd6 10.Bb3 Kc6 11.Bc4 Kd6
  -+  (-2.08)   Depth: 17/17   00:00:00
5...Bf5 6.Kf3 Bc8 7.Kf2 Kd6 8.Bb3 Kc6 9.Bc4 Kd6 10.Bb3 Kc6 11.Bc4 Kd6
  -+  (-2.08)   Depth: 17/17   00:00:00
5...Bf5 6.Kf3 Bc8 7.Kf2 Kd6 8.Bb3 Kc6 9.Bc4 Kd6 10.Bb3 Kc6 11.Bc4 Kd6
  -+  (-2.08)   Depth: 17/17   00:00:00
5...Bf5 6.Kf3 Bc8 7.Kf2 Kd6 8.Bb3 Kc6 9.Bc4 Kd6 10.Bb3 Kc6 11.Bc4 Kd6
  -+  (-2.08)   Depth: 17/17   00:00:00
5...Bf5 6.Kf3 Bc8 7.Kf2 Kd6 8.Bb3 Kc6 9.Bc4 Kd6 10.Bb3 Kc6 11.Bc4 Kd6
  -+  (-2.08)   Depth: 17/17   00:00:00
5...Bf5 6.Kf3 Bc8 7.Kf2 Kd6 8.Bb3 Kc6 9.Bc4 Kd6 10.Bb3 Kc6 11.Bc4 Kd6
  -+  (-2.08)   Depth: 17/17   00:00:00
5...Bf5 6.Kf3 Bc8 7.Kf2 Kd6 8.Bb3 Kc6 9.Bc4 Kd6 10.Bb3 Kc6 11.Bc4 Kd6
  -+  (-2.08)   Depth: 17/17   00:00:00
5...Bf5 6.Kf3 Bc8 7.Kf2 Kd6 8.Bb3 Kc6 9.Bc4 Kd6 10.Bb3 Kc6 11.Bc4 Kd6
  -+  (-2.08)   Depth: 17/17   00:00:00
5...Bf5 6.Kf3 Bc8 7.Kf2 Kd6 8.Bb3 Kc6 9.Bc4 Kd6 10.Bb3 Kc6 11.Bc4 Kd6
  -+  (-2.08)   Depth: 18/18   00:00:00  3kN
5...Bf5 6.Kf3 Bc8 7.Kf2 Kd6 8.Bb3 Kc6 9.Bc4 Kd6 10.Bb3 Kc6 11.Bc4 Kd6
  -+  (-2.08)   Depth: 19/19   00:00:00  20kN, tb=21
5...Bf5 6.Kf3 Bc8 7.Kf2 Kd6 8.Bb3 Kc6 9.Bc4 Kd6 10.Bb3 Kc6 11.Bc4 Kd6
  -+  (-2.08)   Depth: 20/24   00:00:06  373kN, tb=430
5...Bf5 6.Kf3 Bc8 7.Kf2 Kd6 8.Bb3 Kc6 9.Bc4 Kd6 10.Bb3 Kc6 11.Bc4 Kd6
  -+  (-2.08)   Depth: 21/26   00:00:21  990kN, tb=1956
5...Bf5 6.Kf3 Bc8 7.Kf2 Kd6 8.Bb3 Kc6 9.Bc4 Kd6 10.Bb3 Kc6 11.Bc4 Kd6
  -+  (-2.08)   Depth: 22/31   00:00:40  1818kN, tb=4590
5...Bf5 6.Kf3 Bc8 7.Kf2 Kd6 8.Bb3 Kc6 9.Bc4 Kd6 10.Bb3 Kc6 11.Bc4 Kd6
  -+  (-2.08)   Depth: 23/31   00:01:06  2892kN, tb=7525
5...Bf5 6.Kf3 Bc8
  -+  (-2.08)   Depth: 24/36   00:01:49  4950kN, tb=14050
5...Bf5 6.Kf3 Bh3 7.Kg3 Bd7 8.Kf3 Kd6 9.Bb3 Bh3 10.Kg3 Be6 11.Bc2 g4
  -+  (-2.08)   Depth: 25/38   00:05:18  27206kN, tb=53194
5...Bf5 6.Kf3 Bh3 7.Bg8 Bd7 8.Bc4 Kd6 9.Bb3 Bh3 10.Kg3 Be6 11.Bc2 g4
  -+  (-2.06)   Depth: 26/38   00:18:26  45748kN, tb=106862

(,  18.05.2005)

Still a Draw.





>
>>If any subsequent node has an evaluation of more than that
>>then the line is worth persuing.
>
>It could be worth pursuing even if less than that. What if the line has 10 hard
>to find "only moves" in a row, but if, and only if, those moves are found it
>leads to dead equality. It might still be very well be worth pursuing. After
>all, with perfect knowledge every positoin is either win, = or lose. There is no
>position with .13 pawns advantage other than as a fuzzy and subjective measure
>of a positions pratical chances.
>
><snip>
>
>>We humans don't need a backsolving algorithm to tell us what lines to play.
>
>We might, if the opening repertoire we are trying to learn contains 1,000,000
>positions! And we enter a new novelty in a line full of transpositions that
>completely changes the tree. I have seen chess books that give +/- to a certain
>position, and then give -/+ to another position that white can force into the
>+/- position. Needless to say, the book author was not using Bookup and its
>backsolving function. Maybe he should have used it.
>
>>The
>>only time when backsolving would be useful is if by pressing a button one could
>> have a computer immediately tell us all the drawing lines if Chess is a draw
>>and all the winning lines if Chess is a win.
>
>The only time? Or the only time _YOU_ can think of. I can think of many other
>times.
>
>>Of course that will never happen.
>>so in the meantime we all keep adjusting our repertoires with results from games
>>and results from analysis (human or computer engine). So back to the first
>>sentence. once you have a computer analyze a line(or if you do it yourself) if
>>you simply put an evaluation against that node at move 12 why do you need
>>backsolving to fill in all the subsequent nodes by backtracking back up the tree
>>from move 30 back to move 12?
>
>You keep talking about a bushy, tangled tree (an opening database) as though it
>were a linear rope. Chess openings transpose. They have numerous side branches.
>When you make one change to the database, it does NOT affect only one line in
>the database (unless you have a very small, simple database).
>
>>Isn't it much better to have the computer analyze
>>the 12.Ng5 node and then put an evaluation against it than have the 30.Nxg6 node
>>analyzed and then backsolve back up the tree to 12.Ng5?? What purpose does it
>>serve to have all the individual nodes in one line  attached with evaluations
>>when those nodes are not really part of the opening?
>
>It doesn't matter one way or the other. What does matter is all the side
>variations and transpositions. You can't just back up in only one line and get
>the same result.
>
>>Openings are
>>differentiated from the rest of the tree because they are lines that have been
>>proven over the years under practice to be worth repeating. Anybody who thinks
>>backsolving has merit is trying to treat chess as if it is one big opening
>>puzzle with perfect information.
>
>No we aren't. We are trying to treat it as though this is the best information
>we have _so far_. If new information comes along, then that gets added to the
>tree, backsolved, and voila, we have the latest state of the art theory for that
>opening.
>
>>Of course, openings cannot be solved with backsolving.
>
>No one says that they can. Only that it "solves" the opening to the best of our
>knowledge _today_. This is _not_ the same as Ken Thompson solving 5 piece
>endings, and no one is claiming that it is.
>
>>Even the name is wrong. Backsolving does not solve anything.
>
>Sure it does. It solves the minimax problem based on the data and assumptions
>contained within the database. Of course if you mean completely and forever
>solve chess, that is absurd. No one thinks that, no one claims that.
>
>>It
>>merely attaches an evaluation to each node based on an evaluation far down the
>>root of the tree. What use is that when there will be thousands of novelties
>>subsequently found as side lines which will put that line out of business
>>anyway.
>
>This is exactly what makes backsolving so powerful!! When new discoveries are
>made, you add them to the tree, backsolve, and voila; you have the latest
>opening theory completely up to date.
>
>>It is much better to analyze the 12.Ng5 node than to analyze the nodes
>>at move 30. Even GMs who do deep opening analysis have first exhaustively
>>analyzed the nodes at move 12,13,14,15,16,17,18... etc before they do the nodes
>>at move 30.
>
>Of course. With Bookup and backsolving, as with any computer tool, garbage in =
>garbage out. If you use the tool foolishly you will get foolish results. But
>that is not the fault of the tool.
>
>>We will never have perfect information and the chess puzzle will
>>never be completely solved.
>
>Of course. But so what. Backsolving was never intended to "completely solve"
>chess. This is silly.
>
>>I would be very very surprised if any GM ever
>>admitted to ever using the backsolving feature.
>
>I am a corespondence GM, and I have used it.
>
>>My expose of backsolving stands.
>
>You "expose" falls on its face.
>
>>It is simply a waste of bytes.
>
>For you I guess it would be a waste. I and others find it useful.
>
>-Robin
>
>P.S. I don't believe you are "Komputer Korner".



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