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Subject: Re: Twin testposition (outside passers, pawn endgame)

Author: Kurt Utzinger

Date: 13:37:59 03/26/03

Go up one level in this thread


On March 26, 2003 at 16:22:47, Peter Berger wrote:

>On March 26, 2003 at 15:27:39, Kurt Utzinger wrote:
>
>>On March 26, 2003 at 06:28:52, Peter Berger wrote:
>>
>>>These can be tough or very easy depending on engine - some engines seem to know
>>>too much here. They are also interesting for humans I think.
>>>
>>>6k1/p4p2/6p1/1P2p2p/4q2P/4Q1P1/P4P2/6K1 b - - 0 1
>>>
>>>1..Qxe3! wins for black.
>>
>>    Hi Peter
>>    Do you really think that in these positons it is a matter of knowledge
>>    for chess programs?
>
>Yes, I do - see below.
>
>
>I doubt and assume it's simply a matter of search and
>>    calculation.
>
>This depends on the time availlable. You not only want to solve it, but you want
>to solve it fast enough.
>
>
>>We can see this from analysis with Rebel 12 Beta1. In the first
>>    position it's easy to see for the program that white will lose a pawn. In
>>    the second position, Rebel needs 9m2s to come to a slightly negative
>>    evaluation for ... Qxe3?
>
>See?

    Hi Peter
    Sorry, I forgot to post the analysis of Rebel 12 Beta2 for the first
    position where the program sees an win within some seconds only. This
    made me think that it's not a question of chess knowledge.
    Kurt
Thinking....

  +---+---+---+---+---+---+---+---+  End 1 - Pos 1
8 |   |   |   |   |   |   | *K|   |
  +---+---+---+---+---+---+---+---+  00:00:00      00:00:00
7 | *p|   |   |   |   | *p|   |   |
  +---+---+---+---+---+---+---+---+
6 |   |   |   |   |   |   | *p|   |  Time          infinite
  +---+---+---+---+---+---+---+---+  Hash          28 Mb
5 |   | p |   |   | *p|   |   | *p|  Engine        Beta 1
  +---+---+---+---+---+---+---+---+  Personality   beta1.eng
4 |   |   |   |   | *Q|   |   | p |  anti-GM       Off
  +---+---+---+---+---+---+---+---+  Tactics       Off
3 |   |   |   |   | Q |   | p |   |  Bluff Chess   Off
  +---+---+---+---+---+---+---+---+  Style         Normal
2 | p |   |   |   |   | p |   |   |  Strength      Strongest
  +---+---+---+---+---+---+---+---+  Search        Nullmove
1 |   |   |   |   |   |   | K |   |
  +---+---+---+---+---+---+---+---+
    a   b   c   d   e   f   g   h

6k1/p4p2/6p1/1P2p2p/4q2P/4Q1P1/P4P2/6K1 b - -

[Event "?"]
[Site "?"]
[Date "??.??.????"]
[Round "?"]
[White "Pos 1"]
[Black "End 1"]
[Result "*"]
[WhiteElo "?"]
[BlackElo "?"]
[FEN "6k1/p4p2/6p1/1P2p2p/4q2P/4Q1P1/P4P2/6K1 b - - 0 1"]

1..*

00:00:00  1.00  0.18  1..Qxe3 2.fxe3
00:00:00  2.00  0.19  1..Qxe3 2.fxe3
00:00:00  3.00  0.21  1..Qxe3 2.fxe3 f5 3.Kf2 Kg7 4.a4 Kf7
00:00:00  4.00  0.21  1..Qxe3 2.fxe3 f5 3.Kf2 Kg7 4.a4 Kf7
00:00:00  5.00  0.18  1..Qxe3 2.fxe3 f5 3.Kf2 Kf7 4.a4 Ke6
                       5.a5 Kd5 6.Kf3  (0)

00:00:00  6.00  0.18  1..Qxe3 2.fxe3 f5 3.Kf2 Kf7 4.a4 e4
                       5.a5 f4  (0)

00:00:00  7.00  0.21  1..Qxe3 2.fxe3 Kf8 3.Kf2 Ke7 4.a4 Kd6
                       5.Ke2 f5 6.Kd3 Kc5  (0)

00:00:00  8.00  0.21  1..Qxe3 2.fxe3 Kf8 3.Kf2 Ke7 4.a4 Kd6
                       5.Ke2 f5 6.Kd3 Kc5  (0)

00:00:01  9.00  0.39  1..Qxe3 2.fxe3 Kf8 3.Kf2 Ke7 4.Kf3 Kd6
                       5.g4 hxg4 6.Kxg4 f6 7.h5 f5 8.Kg5 gxh5
                       9.Kxh5 Kd5 10.a3  (0)

00:00:01 10.00  0.39  1..Qxe3 2.fxe3 Kf8 3.Kf2 Ke7 4.Kf3 Kd6
                       5.g4 hxg4 6.Kxg4 f6 7.h5 f5 8.Kg5 gxh5
                       9.Kxh5 Kd5 10.a3  (1)

00:00:02 11.00  1.00  1..Qxe3 2.fxe3 Kf8 3.Kf2 Ke7 4.a4 Kd6
                       5.a5 f6 6.e4 Kc5 7.b6 axb6 8.a6  (1)

00:00:03 12.00  1.49  1..Qxe3 2.fxe3 Kf8 3.Kf2 Ke7 4.Kf3 Kd6
                       5.g4 hxg4 6.Kxg4 Kd5 7.Kg5 Ke4 8.Kf6
                       Kxe3 9.Kxe5 f5 10.Kd5 f4 11.Kc4  (2)

00:00:06 13.00  1.80  1..Qxe3 2.fxe3 Kf8 3.Kf2 Ke7 4.a4 Kd6
                       5.a5 f6 6.Ke2 Kc5 7.b6 axb6 8.a6 Kc6
                       9.Kd3 b5 10.Kc3 Kb6  (4)

00:00:11 14.00  1.85  1..Qxe3 2.fxe3 Kf8 3.Kg2 Ke7 4.a4 Kd6
                       5.a5 Kc5 6.b6 axb6 7.a6 Kc6 8.Kf2 b5
                       9.Ke2 b4  (10)

00:00:20 15.00  2.05  1..Qxe3 2.fxe3 Kf8 3.Kf2 Ke7 4.a4 Kd6
                       5.a5 Kc5 6.b6 axb6 7.axb6 Kxb6 8.Ke2
                       e4 9.Kd2 f6 10.Kc3  (15)

00:00:38 16.00  2.09  1..Qxe3 2.fxe3 Kf8 3.Kf2 Ke7 4.Kf3 Kd6
                       5.Ke4 f6 6.Kd3 Kc5 7.Ke4 Kc4 8.a3 Kc5
                       9.b6 axb6 10.Kd3 f5 11.e4  (30)

00:01:38 17.00  2.14  1..Qxe3 2.fxe3 Kf8 3.Kf2 Ke7 4.Kf3 Kd6
                       5.Ke4 f6 6.Kd3 Kc5 7.b6 axb6 8.Kc3 f5  (71)


Positions                :     210.914.796
Nodes per second         :         737.464

Extensions (checks)      :               0 (0%)
Extensions (captures)    :               0 (0%)
Extensions (king safety) :               0 (0%)
Extensions (on depth)    :               0 (0%)
Extensions (remaining)   :               0 (0%)
Extensions (total)       :               0 (0%)

Hash Table               : 22.784.670  9.996.066  (100%)
Average depth            : 23
Deepest depth            : 59


>
>>
>>00:09:02 15.00  -0.15  1..Qxe3 2.fxe3 Kf8 3.Ke2 Ke7 4.Kd3 Ke6
>>                       5.Kc4 f6 6.a3 g5 7.a4 Kd6 8.a5 g4 9.e4  (531)
>>
>
>Crafty might be overtuned for this motive. But if Rebel can't avoid Qxe3 in 9
>minutes trading in a completely lost pawnending it certainly has too little
>knowledge about outside passed pawns here. If it could search deep enough to see
>the trouble tactically it wouldn't matter.
>
>In fact the Rebel evaluation came as a very big surprise for me- it would lose
>this position at tournament time control!
>
>
>Everything in my very humble opinion - I am a user, not a chessprogrammer.
>
>Peter



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