Author: Ernst Walet
Date: 07:03:09 06/10/00
Go up one level in this thread
On June 10, 2000 at 04:23:17, blass uri wrote:
>On June 10, 2000 at 01:01:54, blass uri wrote:
>
>>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
>
>Here is another test position that shows better the importance of knowledge
>about passed pawns.
>
>I composed this position
>
>[D]Q3q3/4k3/8/5p2/2p5/8/P6P/4K3 w - - 0 1
>
>avoid Qxe8+
>
>Century1.2a(p450) can see in less than 5 minutes that Qxe8+ is losing but cannot
>see a better move at least in the first 23 minutes.
>
>I believe that a good evaluation can help to see that white is losing after 2
>plies based on the squares of the pieces.
>
>humans do not know it without search but humans do not have the best evaluation.
>
>Uri
Hiarcs 7.32 does quite well here, bij failing low after 17 seconds and resolving
a better move after 315 seconds on my PIII-450 with 32MB hash.
Analysis by Hiarcs 7.32:
1.Qxe8+ Kxe8
+- (5.38) Depth: 1 00:00:00
1.Qxe8+ Kxe8
-+ (-5.04) Depth: 2/6 00:00:00
1.Qxe8+ Kxe8
-+ (-5.04) Depth: 2/6 00:00:00
1.Qb7+ Kd6+ 2.Kd2
³ (-0.48) Depth: 2/6 00:00:00
1.Qd5 Kf6+ 2.Kd2 Qc8
³ (-0.44) Depth: 2/12 00:00:00
1.Qf3 Qc8
³ (-0.42) Depth: 2/14 00:00:00
1.Qf3 Kd6+ 2.Kd2 Qe5
³ (-0.36) Depth: 3/14 00:00:00
1.Qd5 Qc8 2.a4
³ (-0.34) Depth: 3/14 00:00:00
1.Qxe8+ Kxe8
± (0.98) Depth: 3/16 00:00:00
1.Qxe8+ Kxe8
± (0.98) Depth: 3/16 00:00:00
1.Qxe8+ Kxe8
± (0.73) Depth: 4/16 00:00:00
1.Qxe8+ Kxe8
± (0.73) Depth: 4/16 00:00:00
1.Qxe8+ Kxe8
² (0.35) Depth: 5/16 00:00:00 6kN
1.Qxe8+ Kxe8 2.a4 Kd7 3.a5 Kc6 4.Kd2
= (-0.25) Depth: 5/16 00:00:00 7kN
1.Qxe8+ Kxe8 2.a4 f4 3.a5 Kd8 4.h4 Kd7 5.h5
³ (-0.34) Depth: 6/21 00:00:02 159kN
1.Qxe8+ Kxe8
= (-0.09) Depth: 7/23 00:00:12 866kN
1.Qxe8+ Kxe8 2.a4 c3 3.a5 Kd7 4.a6 Kc8 5.a7 Kb7 6.a8Q+
+- (4.61) Depth: 7/24 00:00:12 891kN
1.Qxe8+ Kxe8 2.a4 f4 3.a5 Kd7 4.a6 Kc6 5.a7 Kb7 6.h4 Kxa7
+- (4.79) Depth: 8/25 00:00:13 925kN
1.Qxe8+ Kxe8
+- (4.50) Depth: 9/25 00:00:13 987kN
1.Qxe8+ Kxe8 2.a4 f4 3.a5 Kd7 4.a6 Kc6 5.h4 c3 6.h5 c2 7.Kd2 f3 8.a7 c1Q+ 9.Kxc1
-+ (-5.55) Depth: 9/25 00:00:17 1328kN
1.Qd5 Kf6+ 2.Kd2 f4 3.Qxc4 Qe3+ 4.Kc2 Qf2+ 5.Kc3 Qe1+ 6.Kb2 Qd2+ 7.Qc2 Qb4+
8.Kc1 Qe1+ 9.Qd1
= (0.00) Depth: 9/29 00:05:15 25748kN
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