Author: blass uri
Date: 22:01:54 06/09/00
Go up one level in this thread
On June 09, 2000 at 18:11:37, Ed Schröder wrote:
>On June 09, 2000 at 05:39:21, blass uri wrote:
>
>>On June 09, 2000 at 01:11:03, Paulo Soares wrote:
>>
>>>On June 09, 2000 at 00:08:07, Oliver Roese wrote:
>>>
>>>>On June 09, 2000 at 00:03:02, Paulo Soares wrote:
>>>>
>>>>>On June 08, 2000 at 22:49:28, Oliver Roese wrote:
>>>>>
>>>>>> [Event "NRW 4er-Pokal"]
>>>>>> [Site "Germany"]
>>>>>> [Date "2000.06.04"]
>>>>>> [Round "?"]
>>>>>> [White "Grimm, S."]
>>>>>> [Black "N.N"]
>>>>>> [Result "1/2-1/2"]
>>>>>> [FEN "8/4k1pp/5p2/P1p1p3/2Qq4/1P4P1/5PKP/8 b - - 0 1"]
>>>>>>
>>>>>> 1...Qxc4 ({This position occured last sunday in a team event. It was the
>>>>>>last game. I and a team colleague of mine were "kibitzes". Our man had white.
>>>>>>Obviously black is in trouble here. But black has the chance here to swap the
>>>>>>queens and go into a pawn ending. He pondered a while and finally he played
>>>>>>1...Qd6. The game went on with 2.Qe4 and finally he lost. My teammate took me
>>>>>>aside: "What do you think about 1.Qxc4?" he asked. "Well, white opens the
>>>>>>kingside with g4 and wins.", i said. "Wrong!" he told me. We made a blindgame,
>>>>>>me playing white and he took me along up to the 18th move in this analysis. "I
>>>>>>see.", i said, "But maybe white has some other possibilities." I went to the
>>>>>>board, puzzled a while, and came back. "What about f4?" i asked. He hesitated
>>>>>>shortly and showed me the winning line for black. In a few seconds he refuted a
>>>>>>line that costed me several minutes! I went to the board again, trying hard to
>>>>>>refute Qxc4. Eventually i came back. "What about g4, Kg3 and then f4?" He
>>>>>>ponderd a while and then quick as a flash he showed me the refutation again. "So
>>>>>>this guy is tough!", i concluded for myself. After the end of the game, we
>>>>>>showed them what he had found. They were both surprised. Finally we were
>>>>>>interested to see if there are any winningchances in the resulting QQ-endgame.
>>>>>>Should i tell you who told us 19..Kc2 ? This is one of the few examples, there
>>>>>>a skilled human can outperform current hard/software. If they can solve it all!
>>>>>>I tried a few minutes with crafty, but gave up at the end. Can your computer
>>>>>>come up with 1...Qxc4! ? Oliver Roese } 1...Qd6 ) 2.bxc4 Kd6 3.g4 ( 3.f4??
>>>>>>exf4 4.gxf4 f5 -+ 5.Kg3 g6 6.Kh4 ( 6.h4 h5 ) 6...h6 ) 3...g6 4.Kf3 ( 4.Kg3?? Kc6
>>>>>>5.f4 Kb7 6.fxe5 fxe5 7.Kf3 Ka6 8.Ke4 Kxa5 9.Kxe5 Kb4 10.Kd5 g5 -+ ) 4...f5
>>>>>>5.gxf5 gxf5 6.Kg3 Kc6 7.Kh4 h6 8.Kh5 e4 9.Kh4 Kb7 10.Kg3 Ka6 11.Kf4 Kxa5 12.Kxf5
>>>>>>Kb4 13.Kxe4 Kxc4 14.f4 Kb3! 15.f5 c4 16.f6 c3 17.f7 c2 18.f8=Q c1=Q = 19.Qb8+
>>>>>>Kc2! 20.Qc7+ Kd1 21.Qxc1+ Kxc1 22.Kf5 Kd2 23.Kg6 Ke3 24.Kxh6 Kf4 1/2-1/2
>>>>>
>>>>>I think 3.Kf3! is a winner move. Black have no chances.
>>>>>
>>>>>1... Qxc4 2. bxc4 Kd6 3. Kf3!
>>>>>
>>>>>Paulo Soares, from Brazil
>>>>
>>>>But _why_ do you think that?
>>>
>>>I was wanting to place the answer quickly in the forum and I analyzed the
>>>position believing in the evaluation of the program, without giving the
>>>necessary time for a good evaluation. My mistake, sorry.
>>>
>>>1... Qxc4 2. bxc4 Kd6 3. Kf3 f5 {!}
>>>4. g4 g6 5. gxf5 gxf5 6. Kg3 Kc7 7. Kh4 h6 8. Kh5 e4 9. Kh4 Kb7 (9... f4 10.
>>>Kg4 e3 11. fxe3 fxe3 12. Kf3 {+-}) 10. Kg3 Ka6 11. Kf4 Kxa5 12. Kxf5 Kb4 13.
>>>Kxe4 Kxc4 14. f4 Kb3 15. f5 c4 16. f6 c3 17. f7 c2 18. f8=Q c1=Q {=}
>>>
>>>Paulo
>>
>>The problem is that programs do not know to evaluate unstoppable pawns
>>
>>try the following position that can happen after
>>3.Kf3 f5 4.g4 g6 5.gxf5 gxf5 6.kg3 Kc6 7.Kh4 h6 8.Kh5 e4 9.a6 Kb6 10.Kxh6 f4
>>
>>
>>[D]8/8/Pk5K/2p5/2P1pp2/8/5P1P/8 w - - 0 1
>>
>>Programs cannot see at evaluation time that black is winning because of
>>unstoppable pawn.
>>
>>If I give them to analyze at 1 ply depth they give a big advantage for white.
>>
>>part of the programs know that h2 is unstoppable but they do not know that e4 is
>>unstoppable and that e4 can be a queen faster than h2
>>
>>Uri
>
>You can solve a problem in 2 ways, a) with chess knowledge or b) by search.
>Very often search is much more powerful than adding complex and processor
>time stealing complex chess knowledge. This position is a typical example
>that search is the right solution to play the best move.
>
>Ed
The problem is not this position but the position many plies before.
programs did a mistake in the evaluation of the position many plies before
probably because they did not give the right static evaluation to this position.
I believe that it is important to see big positional scores at evaluation time
because of this reason.
Uri
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