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Very Hot Topic (More than 25 Replies) My trusty engine tells me Chess Truth (Read 45022 times)
Michael Ayton
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Re: My trusty engine tells me Chess Truth
Reply #16 - 11/03/11 at 14:22:48
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My Houdini is weird! In the first position it plays 1 ...Qh6, giving it as winning and making me think it's [i]possible[/i] it's gone for this having evaluated it as actually stronger than 1 ...g3 2 h3 Bh3. Then, if I input 1 ...g3 it then sees 2 h3 Bh3 immediately (playing 2 hg in fact), but when I input 2 h3 as well, it plays 2 ...Nc8. Weird! ...
  
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Vass
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Re: My trusty engine tells me Chess Truth
Reply #15 - 11/03/11 at 14:09:02
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Smyslov_Fan wrote on 11/03/11 at 13:41:46:
Thx, Vass! I'm amazed that the engines can't see that plan. But then, I've found that even now, Roman Dzindzichasvili's old (1990s) method of using pawn storms to crush engines still works in correspondence.

You're welcome!..  Cool
Amazingly, even in the positions that are highly tactical the engines can't do without the correspondent player. At least, when a strategy is needed.. Look at this example:
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This one is from a correspondent chess game, too.. Every correspondent player will try to analyze the winning move 1.Ncxe5!! first.. Try some Houdini's or Rybka's!.. They can see it in 27-depth  Shocked, at least.. While the human strategy is simple: sac the knight for two pawns (Kh8-h7 is a must), exchange the c-file rooks (Rc1xc8, Rfxc8 is compulsory, too), then move the queen along f3-g4-f5 route and...you can help yourself with some engines if you're lazy..  Wink
The pawn storm is coming..  Grin
  
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Re: My trusty engine tells me Chess Truth
Reply #14 - 11/03/11 at 14:08:56
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one of my favorite games is still this: http://www.chessgames.com/perl/chessgame?gid=1048284
A game which computers still don't understand the forced win for white. It came up as a 'test your strength' puzzle on chessgames.com Everyone cheated and declared the position drawn by writing down their computer's analysis. While Shirov did  not play the best defense, the game is heavily analyzed by Gelfand in his 300 best games book. All the computer moves are refuted by Gelfand's analysis to wins. No draw!
  
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Smyslov_Fan
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Re: My trusty engine tells me Chess Truth
Reply #13 - 11/03/11 at 13:41:46
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Thx, Vass! I'm amazed that the engines can't see that plan. But then, I've found that even now, Roman Dzindzichasvili's old (1990s) method of using pawn storms to crush engines still works in correspondence.
  
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Re: My trusty engine tells me Chess Truth
Reply #12 - 11/03/11 at 12:01:04
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As correspondence chess players know...the engines are far from perfection. One may look at this position with Houdini, Rybka or whatever and never find the win for black (position taken from a correspondence chess game):
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Then try to think yourself, analyze a bit...and you'll see:
1... g3! 2. h3 Bxh3! 3. gxh3 g2 4. Rfc1 Qh4-+  Cool
They use to to say correspondence chess is dead. Yes, it's dead...when relying only on machines.  Wink
  
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fling
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Re: My trusty engine tells me Chess Truth
Reply #11 - 11/03/11 at 08:35:10
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bragesjo wrote on 11/02/11 at 10:13:55:
About engines, often different engines tells completly different things in complicated positions.
I remember a certain sharp Dragon line where first engine says white is winning and second engine says black is slightly better and the truth was the black was much better.


This was precisely my first point. And it was a comment on the idea that Houdini should be the best engine. It turned out that statement was because it won a match (don't remember the exact details, but not even a useful set-up IMO - too short analysis time) against other engines.

Well of course different engines will give different evaluations depending on their algoritms. And their main strength is not long-term planning. Nothing new, really. I guess the question is when in practical terms we humans won't be able to improve the analysis.
  
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trw
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Re: My trusty engine tells me Chess Truth
Reply #10 - 11/03/11 at 04:41:37
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Smyslov_Fan wrote on 11/02/11 at 12:42:42:
Agreed, bragesjo. I've seen on another site how some ppl are beholden to the computational power of Houdini over everything else. Yet Fritz will often have a more accurate evaluation of the position. I'm not the first to have noticed this by a long shot. There was an article over on ChessCafe that discussed the strengths and weaknesses of various engines in correspondence chess. Of course, I still believe that humans have the best evaluative skills in positions such as this unless there's a mathematical proof of a draw.


Can you link to that article?


BTW, I also concur with Markovich and MNB. Chess engines are not god and they are not telling 'Chess Truths'
  
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Smyslov_Fan
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Re: My trusty engine tells me Chess Truth
Reply #9 - 11/02/11 at 12:42:42
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Agreed, bragesjo. I've seen on another site how some ppl are beholden to the computational power of Houdini over everything else. Yet Fritz will often have a more accurate evaluation of the position. I'm not the first to have noticed this by a long shot. There was an article over on ChessCafe that discussed the strengths and weaknesses of various engines in correspondence chess. Of course, I still believe that humans have the best evaluative skills in positions such as this unless there's a mathematical proof of a draw.
  
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bragesjo
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Re: My trusty engine tells me Chess Truth
Reply #8 - 11/02/11 at 10:13:55
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About engines, often different engines tells completly different things in complicated positions.
I remember a certain sharp Dragon line where first engine says white is winning and second engine says black is slightly better and the truth was the black was much better.
  
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Smyslov_Fan
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Re: My trusty engine tells me Chess Truth
Reply #7 - 11/02/11 at 09:34:32
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Well, the position I created at random was to illustrate that while engines may consider a material imbalance in favor of one side, humans have a different sense.

Here's a slightly revised version of the same material imbalance that is a bit more clearly in White's favor. I'm not claiming a win for White, but I'd definitely prefer to play that side. I wonder how many humans would prefer to play Black?

Firebird considers the position to be equal (+0.09) at a depth of 20 ply. The goal here isn't so much to find absolute truth as to point out a basic flaw in the calculus of material that this family of engines consistently exhibit.

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And here's another similar position:
Firebird gives this as 0.00 at 20 ply. I think most humans would LOVE to play White in a correspondence game.
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micawber
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Re: My trusty engine tells me Chess Truth
Reply #6 - 11/02/11 at 07:51:51
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I can understand why the position in question is eventually equal. Without calculating a lot of variations 
For White to win he must prevent that Black exchanges his pawn and 2 pieces against the 3 pawns (2 lonely knights cant deliver mate). That may prove extremely difficult, especially since the 'defenders' king is in front of the passed pawn(s).
But there are plenty of other endgame positions that are too difficult for engines at this moment (perhaps not in the future). Another example are positions with R+p vs. B+Kn, Rook end-games with multiple pawns (4p vs 3p) are often too difficult for a correct evaluation.
I also appreciate the comments on gambits. Especially those gambits where compensation for a pawn in a semi-closed position is in the nature of a creeping initiative
where you can slowly improve your position further and the opponent has been robbed of any pawn-brakes.
  
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Re: My trusty engine tells me Chess Truth
Reply #5 - 11/01/11 at 16:29:35
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This Topic was moved here from 1. e4 e5 - Non-Spanish [move by] Markovich.
  

The Great Oz has spoken!
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Re: My trusty engine tells me Chess Truth
Reply #4 - 11/01/11 at 10:19:50
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Centaur >> Engine, of course. I  agree with it.

@Smyslov_Fan,

I know there are some positions which engines can't understand in a reasonable time, or never. I have a very sweet position like this in my mind too. Fact is this position is also a sharp tactical position, there is a forced mate, and engine couldn't solve it! I have solved it with playing pieces in half hour on my chessboard. Meanwhile Rybka was pondering the solution but she couldn't find until i finish my solution.

I have analyzed your position with my engine, only 4 million nodes and the result is 0.00. I agree with Houdini, white can't win. But i would prefer white here, as whites play easier than blacks. Here is the analysis:

Analysis by Houdini 2.0 Pro x64:

1.Nf6+ Kc7 2.c4 Rh4 3.Ng4 Bg6+ 4.Ne4 Bf5 5.Ne5 Be6 6.Nc5 Bc8 7.Ne4 Rh5 8.Kc3 Be6 9.Nc5 Bc8 10.Ne4 Be6
=  (0.00)    Depth: 32/20   00:06:38  3878mN


And i waited some more:

Analysis by Houdini 2.0 Pro x64:

1.Nf6+ Kc7 2.c4 Rh4 3.Ng4 Bg6+ 4.Ne4 Bf5 5.Ne5 Be6 6.Nc5 Bc8 7.Ne4 Rh5 8.Kc3 Be6 9.Nc5 Bg8 10.Ne4 Rf5 11.Kb4 Bf7 12.Kc5 Bh5 13.Nd6 Rf6 14.Ne4 Rf5 15.Nd6
=  (0.00)    Depth: 34/54   00:22:50  11685mN

Again the same, with deeper line.



I tried to setup my position but couldn't remember completely for now. Maybe later.


  

...You must take your opponent into a deep dark forest where 2+2=5, and the path leading out is only wide enough for one...
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Re: My trusty engine tells me Chess Truth
Reply #3 - 10/31/11 at 06:37:33
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MNb wrote on 10/30/11 at 13:44:10:
I confirm this. My only loss in the CL occurred by playing an Exchange sac which was equal according to my engines (including Houdini), but not to my (strong) opponent.

Only loss? Man, you did well.
  

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Re: My trusty engine tells me Chess Truth
Reply #2 - 10/30/11 at 21:54:52
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I completely agree with Markovich and MNb.

Piling on a bit, but for a good cause: There are some websites where it seems that computer analysis is treated as heaven-sent wisdom. Thank Heavens this isn't one of them!

Experienced correspondence players love these gambits precisely because the computers mis-evaluate them on a regular basis. My feeling is that this may be one of the weakest spots in computer analysis, along with material imbalances such as Rook+B vs 2 Knights and 2 pawns. Sure, computers have made huge improvements over the years, but the savvy analyst who uses engines and his own experience will almost always trump the pure engine user.

Here's a random example of a position that I would evaluate as very good for white but the Rybka/Firebird/Houdini family would consider to be slightly in Black's favor:

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