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Yelena Dembo
Member since Jan-21-06
WGM/IM Yelena Dembo, 26 years old. FIDE rating of 2470, I live in Athens, Greece. You can find more info about me and 3 books I wrote on my personal website - www.yelenadembo.com. Their names are: "The Very Unusual Book About Chess" which deals with middlegame methods and the second one - "Conversation with a Professional Trainer - Methods of Positional Play". The 3rd book is "Play the Gruenfeld", written for Everyman, and you can buy it on www.amazon.com. I have a large collection of theory - best lines for the necessary colours with my own novelties partly published in Informants, so you dont have to choose the line you want to play from the books!The theory is not expensive and is in ChessBase/Fritz format. Let me know if you are interested. A lot of people buy it.For example, King's Indian is 60 euro. Voice LESSONS ARE NOW POSSIBLE WITH SKYPE!
>> Click here to see Yelena Dembo's game collections.

Chessgames.com Full Member

   Yelena Dembo has kibitzed 225 times to chessgames   [more...]
   Apr-14-13 Yelena Dembo (replies)
 
Yelena Dembo: Thank you, guys! :) Best wishes!
 
   Sep-18-10 Yelena Dembo chessforum (replies)
 
Yelena Dembo: Ah, and let's not forget that the average rating of my opponents there was about 1800 :-) So no wonder I won almost all my games :) Still drew some 10 or so...
 
   Sep-18-10 Balanel vs Larsen, 1956 (replies)
 
Yelena Dembo: Wonderful game. Knight's transfer was very typical! Good to remember.
 
   May-15-10 Short vs Psakhis, 1999 (replies)
 
Yelena Dembo: A wonderful game!
 
   May-15-10 US Championship (2010) (replies)
 
Yelena Dembo: Well, there is a small element of luck in chess, but it is really small :-D
 
   Feb-17-09 Topalov vs Kamsky, 2009 (replies)
 
Yelena Dembo: Ok, so he actually took a draw:-) Strange, why not repeat the moves like he did earlier...
 
   Oct-17-07 Judit Polgar vs Short, 1993 (replies)
 
Yelena Dembo: Nice game especially for blindfold chess!!
 
   Oct-17-07 Grunfeld (D90) (replies)
 
Yelena Dembo: This is a recent review of my book on Gruenfeld by Jeremy Silman. Enjoy! http://www.jeremysilman.com/book_re...
 
   Jun-26-06 AdrianP chessforum (replies)
 
Yelena Dembo: Hello! My second book titled "Conversation with a Professional Trainer - Methods of Positional Play" is getting published now and will be out on Tuesday or Wednesday! It has a large amount of themes: Chapter One - Opening Problems 9 Chapter Two - How to Improve Part One 13 ...
 
   Apr-12-06 7th European Individual Championship: Women (2006) (replies)
 
Yelena Dembo: The new website of the European championship is now www.tsf.org.tr
 
(replies) indicates a reply to the comment.

Kibitzer's Corner
< Earlier Kibitzing  · PAGE 13 OF 13 ·  Later Kibitzing>
Oct-14-10  nvrennvren: really ?

it was a good lesson from online games, at least warned her not to do it in regular games

Oct-19-10  cotoi: cotoi: Well, Yelena didn't admit that she used engine assistance, that site backed up and no longer claim that her account was closed for cheating. So, what is left are some perfect games, the only games in a history where apparently an unassisted human plays exactly like Rybka. It is very interesting to see how, in a quiet position with 5-6 good candidate moves, Yelena always seems to pick the best, even if the difference between it and the second-best is like two centipawns. A mystery, indeed.
Nov-18-10  heth: This is the "slightly above 2000" player who played white in that Olympiad game cited in this thread. Here are some general comments about the game.

I was extremely fortunate to get something I had prepared - the moves up to 11.a3 were made very quickly by both players, when I was then able to follow some Richard Palliser analysis and gain time on the clock until around move 17.

With this in mind, I would be interested to know what my engine matchup was for the white moves in this game.

We both spent a lot of time around move 25, where 25... Nxd4 is a candidate move that initially looks very good for black then looks less good the further you analyse.

This left both players racing to get to move 40, with various mutual blunders exchanged close to the time control - it became a bit of a blitz game. I would assume that the engine matchup for this portion of the game would be relatively low for both players (until the repetition at the end of course).

Nov-19-10  Zygalski: Heather:
Match rates from one game mean very little at all (at least inasmuch as finding cheats in online chess) but I'll run the analysis with Houdini 1.03a later.

bartonlaos:
The rate from this single cherry-picked OTB game may well be high for Yelena, we'll see. Thing is, the as you call it 'arbitrary'

Top 1 Match: 65%
Top 2 Match: 80%
Top 3 Match: 90%

engine match up rates thresholds which also include +5% headroom over benchmark results refer to 20 or more games with 400+ non-database move sample size. The games need to be objectively chosen, eg the most recent 20 games vs 2200 rateds all found to have 20 or more non-database moves.

As such, Yelena has already been tested:

"I picked the last 20 games >= 35 moves from chessgames.com. All against high-rated opposition (lowest ELO in the set is 2222, highest is 2655)"

The results of the analysis:
Dembo OTB games:
Stockfish 1.8, 512MB hash, min/max ply=12/30, 40s/ply, 2GHz Core Duo:

Yelena Dembo (Games: 20)
{ Top 1 Match: 422/929 ( 45.4% )
{ Top 2 Match: 615/929 ( 66.2% )
{ Top 3 Match: 717/929 ( 77.2% )
{ Top 4 Match: 777/929 ( 83.6% )

Nov-19-10  Zygalski: Here is the analysis.
I used Houdini 1.03a x64 4_CPU on a 4 x AMD Phenom 2.30GHz 4GB RAM system.

The engine was given 60 seconds minimum per ply to analyse to depth 16-22. Under these conditions Houdini almost always reached depth = 20 & often managed depth = 21 or 22.

The analysis output log is in the format played move, top 1 match move, top 1 match score, top 1 match depth reached, top 2 match move & so on. For instance, at move 33 Black played Ba8. Houdini preferred 33...a3, scoring it +0.88 at depth = 21. The played move (asterisked) was the engine's 3rd choice, scoring +1.64 at depth = 21.

According to the analysis, White seemed to have all the play, gradually building to +1.20 until 27.Rxa5 when the score reverted to 0.00. Black dropped over a pawn on move 33 & White blundered on move 38, though Black failed to take advantage.

Nov-19-10  Zygalski: [Event "Chess Olympiad (Women)"]
[Site "Khanty-Mansiysk RUS"]
[Date "2010.09.23"]
[Round "3"]
[White "Heather Lang"]
[Black "Yelena Dembo"]
[Result "1/2-1/2"]
[ECO "A07"]
[WhiteElo "2025"]
[BlackElo "2452"]
[PlyCount "84"]
[Analysis "Houdini 1.03a x64 4_CPU Hash:512 Time:60s Depth:16-22ply"]

Database Moves:

1. e4 c5 2. Nc3 Nc6 3. g3 g6 4. Bg2 Bg7 5. d3 d6 6. Be3 Nd4 7. Qd2 Qa5 8. f4 e6 9. Nf3 Ne7 10. 0-0 Nec6 11. e5

Analyzed:

11... d5 *d5 16 20* : ♘f5 34 20 : ♘xf3+ 37 20 : 0-0 36 19

12. a3 ♗xd4 14 21 : *a3 16 20* : a4 8 20 : ♖fd1 7 20

12... Nxf3+ f6 7 20 : ♗d7 17 19 : a6 26 19 : 0-0 29 19

13. Bxf3 *♗xf3 29 21* : ♖xf3 -100 20 : ♔h1 -1149 20 : ♔f2 -1180 20

13... 0-0 f6 27 20 : *0-0 31 20* : g5 49 20 : f5 66 20

14. b4 *b4 39 22* : ♘e2 6 22 : ♗f2 -1 21 : ♘b1 -1 21

14... cxb4 *cxb4 32 21* : ♕c7 119 21 : ♕d8 119 20 : ♕b6 182 20

15. axb4 *axb4 36 22* : ♘e2 -3 21 : ♘a2 -42 21 : ♘d1 -64 21

15... Qxb4 *♕xb4 28 21* : ♕d8 88 21 : ♕c7 115 20 : ♕xa1 704 20

16. Rfb1 *♖fb1 34 21* : ♖a4 6 21 : ♖ab1 0 21 : d4 0 21

16... Qe7 *♕e7 34 21* : ♘xe5 274 21 : ♘d4 375 21 : d4 494 21

17. Qf2 *♕f2 36 20* : ♘b5 15 20 : ♕e2 0 20 : ♘a4 -2 20

17... Re8 ♕d7 35 21 : ♖d8 35 21 : ♕d8 43 21 : d4 40 20

18. Bc5 ♘b5 40 20 : *♗c5 40 20* : ♗b6 35 20 : ♔g2 24 20

18... Qd7 *♕d7 41 21* : ♕d8 53 20 : ♕c7 111 20 : ♗xe5 441 20

19. Nb5 *♘b5 41 19* : ♔g2 27 19 : ♗g2 27 19 : h4 19 19

19... f6 *f6 43 20* : b6 60 20 : ♗f8 89 20 : a5 77 19

20. d4 *d4 48 20* : exf6 17 19 : ♘d6 0 19 : ♘xa7 -11 19

20... b6 fxe5 50 20 : ♖d8 54 20 : a6 54 19 : *b6 54 19*

Nov-19-10  Zygalski: 21. Bd6 *♗d6 54 21* : ♗xb6 45 20 : ♗a3 6 20 : exf6 5 20

21... Bb7 fxe5 54 20 : *♗b7 54 20* : h6 87 20 : ♗h8 89 20

22. Nc7 *♘c7 54 19* : c4 0 19 : ♕g2 -4 19 : ♗g2 -10 19

22... Rec8 fxe5 53 21 : ♖ed8 66 21 : *♖ec8 57 20* : ♖f8 57 20

23. Nxa8 *♘xa8 64 20* : ♘b5 -75 20 : c4 -78 20 : ♘a6 -81 19

23... Bxa8 ♖xa8 54 20 : *♗xa8 76 20* : ♘a5 259 19 : fxe5 318 19

24. Be2 ♗g4 71 20 : c3 71 20 : *♗e2 61 20* : ♖a2 52 20

24... fxe5 *fxe5 65 20* : ♘a5 85 20 : ♕f7 90 20 : ♖d8 104 20

25. fxe5 *fxe5 99 20* : ♗xe5 67 20 : dxe5 52 20 : ♗a6 26 19

25... Na5 *♘a5 96 21* : ♘e7 110 21 : ♘xd4 110 21 : ♘d8 132 21

26. Ba6 *Ba6 92 21* : Bb5 80 21 : c3 75 21 : Rf1 60 21

26... Rd8 *Rd8 90 20* : Re8 127 20 : Nc6 359 20 : Rc3 720 20

27. Rxa5 Bb4 120 20 : c3 103 20 : Qf1 93 20 : Qf4 88 20

27... bxa5 *bxa5 0 19* : Bc6 655 19 : Bh6 882 19 : Qf7 892 19

28. Qd2 Rf1 0 22 : Qf4 0 22 : c3 0 22 : Qf3 0 22

28... a4 *a4 0 22* : Bf8 33 22 : Bc6 50 22 : Re8 56 22

29. Qb4 Qg5 0 22 : Qa5 0 22 : Bc5 -7 22 : Bd3 -14 22

29... Bc6 Bf8 -5 22 : Bh6 -5 22 : *Bc6 0 22* : Re8 20 22

30. Rf1 *Rf1 0 22* : Bc5 -5 22 : Kg2 -16 22 : Be7 -20 22

30... Re8 *Re8 0 22* : Kh8 0 22 : Bh6 0 22 : Ra8 0 22

31. Qc5 *Qc5 0 22* : Rf3 0 22 : Kg2 0 22 : Kh1 0 22

31... Bh6 *Bh6 0 21* : Rd8 67 21 : a3 48 20 : Ra8 56 20

32. Rf3 Kg2 0 22 : h4 0 22 : Kh1 0 22 : *Rf3 0 22*

32... Rd8 Bc1 0 22 : Bd2 0 22 : Bg5 50 22 : a3 56 22

33. Rc3 *Rc3 88 22* : Kg2 0 22 : Rf1 0 22 : h4 0 22

33... Ba8 a3 88 21 : Bb7 116 21 : *Ba8 164 21* : Bd2 164 21

34. Bb5 Kg2 187 22 : Kf2 104 21 : Bc8 79 21 : Qb5 64 21

34... Qf7 Qb7 39 19 : *Qf7 190 19* : Bc6 597 19 : Be3+ 638 19

35. Be7 Kg2 206 22 : Be2 41 22 : Qc7 21 21 : Bxa4 20 21

35... Bf8 *Bf8 0 19* : a6 585 19 : Bd2 593 19 : Bc1 738 19

Nov-19-10  Zygalski: 36. Bd6 *Bd6 0 21* : Qxa7 -11 21 : Bxd8 -357 20 : Bxa4 -380 20

36... Bxd6 *Bxd6 0 22* : a3 0 22 : Bb7 0 22 : a6 61 22

37. exd6 *exd6 0 21* : Qxd6 -363 21 : Be8 -1416 20 : Rf3 -1642 20

37... Rf8 *Rf8 0 22* : a3 0 22 : Bc6 0 21 : Bb7 12 21

38. Qc8 d7 0 21 : Kh1 0 21 : Kg2 -8 21 : Bd3 -340 21

38... Qf2+ Bb7 -563 19 : a6 -137 18 : *Qf2+ 0 18* : Qf6 0 18

39. Kh1 *Kh1 0 22*

39... Qe1+ *Qe1+ 0 22* : Qf5 0 22 : Rxc8 0 22 : Kh8 0 22

40. Kg2 *Kg2 0 4* : Bf1 -#1 3

40... Qd2+ *Qd2+ 0 22* : Rxc8 0 22 : a3 0 22 : Qf2+ 0 22

41. Kh3 *Kh3 0 21* : Kh1 0 21 : Kg1 -1396 21 : Be2 -#32 21

41... Qh6+ *Qh6+ 0 19* : Rxc8 0 19 : Qf2 501 19 : a3 598 19

42. Kg2 *Kg2 0 4* : Kg4 -#1 3

42... Qd2+ *Qd2+ 0 21* : Rxc8 0 21 : g5 263 21 : Qg7 543 20

1/2-1/2

Game Summary

White: Heather Lang
{ Top 1 Match: 21/31 ( 67.7% )
{ Top 2 Match: 23/31 ( 74.2% )
{ Top 3 Match: 24/31 ( 77.4% )
{ Top 4 Match: 25/31 ( 80.6% )

Black: Yelena Dembo
{ Top 1 Match: 20/32 ( 62.5% )
{ Top 2 Match: 24/32 ( 75.0% )
{ Top 3 Match: 28/32 ( 87.5% )
{ Top 4 Match: 29/32 ( 90.6% )

Nov-23-10  bartonlaos: <heth> I'm posting much cleaner results to your player's page, Heather Lang.
Nov-23-10  bartonlaos: <Zygalski>

Do you remember writing this: <"the top 4 matchup methodology as outlined by me is totally flawed."> Because if you did, then you'd realize how silly you sounded just now, outlining the flawed methodology. And such a terribly messy presentation of your results! A cluttered mind, perhaps?

To help clean up your method, try this for an improvement: you cannot adjust engine-depth level willy-nilly throughout the testing process. Pick one depth and stick to it.

Another fatal flaw. In Yelena's OTB set that you proudly cite, 16 of the games were from the same tournament. Did you know this? You cannot do that. We all have good and bad tournaments, too many games can influence the overall effect and not be representative of a player's ability.

Additionally, only 4 games were from opponents hundreds of points below Dembo's own. A player performs better against lower-rated opponents. This is because chess is about taking advantage of mistakes, which are greater in degree when made by lower-rated opponents. This is why Heather's game with Yelena is important - because it demonstrates that Yelena's performance against a much lower-rated opponent OTB is on par with her Chess.com performance. Remember that 19/20 games in Yelena's set at Chess.com were against opponents rated 300 points lower than her own. Yet their results were used to influence the downstream interpretations. Tsk, tsk! You should be ashamed for the cherry-picking role you played in this.

So the question being asked by the Lang-Dembo game, is: <Can Yelena perform at a similar level to her Chess.com correspondence results if she played OTB against a much lower-rated opponent?> The answer is <"YES, she can!">

So I wasn't the one who cherry-picked, but needed to ask an important question. This is because the games in the set you created had been cherry-picked to boost the rating scale. This is a boomerang to what you said earlier, "that cherry-picked game(s) mean nothing in terms of this methodology". LOL! Your flawed methods are also corrupted. Since relative rating differences influence a player's performance, cherry-picking means everything, and reflects upon the lack of your integrity.

Nov-24-10  Zygalski: Bartonlaos
Clearly you're a fan of Yelena as you've always been highly supportive of her throughout this affair. Can I task you with attempting to find a move where Yelena dropped greater than 0.25 of a pawn at depth of 20 in any of her chess.com games because after all, to err is human... Best of luck.
Nov-24-10  Zygalski: Also, if it's a fatal flaw to select chess.com games where Yelena played against players several hundred points lower than her, can I ask why you decided to break your own rule by showcasing a single game where a near 2500 IM is playing someone rated just over 2000? Sounds like a confused mind to me.
Nov-24-10  Zygalski: Finally, you can scream like a child about how imperfect any method is, but in the final analysis another International Master - David Pruess - analysed Yelena's games and found overwhelming evidence of engine use and closed her chess.com account.

I agree that labelling anyone a known cheat is at best dicey, but chess.com have other information stored on their servers which, combined with consistent high engine match up in balanced positions in many games, would be highly embarrassing should it be revealed & would leave no sane person with any shred of doubt as to what events took place.

Dec-04-10  croco: heth: engine match-up for a single game is far from being significant. In the game you mentioned there were many forcing moves and at the end there was one huge mistake made by your opponent. This type of engine match-up analysis may become significant only when many games are considered.

zygalski: As far as I can see now, Yelena's account on chess.com is closed and there is no mention of cheating. How do you know that David Pruess analyzed her games and where is that analysis?

It appears to me that either chess.com made a huge mistake or, if not, they don't have the courage to assume their decision. Which means that they don't trust their detection methods.

Dec-05-10
Premium Chessgames Member
  dkappe1: This little dembo witch hunt reminds me of the "it's a rybka clone" witch hunts over in the chess engine world. Apparently every chess engine of any strength has to be a Rybka clone.

These chess.com sock puppets make an excellent case for restricting comments to premium members.

Dec-05-10
Premium Chessgames Member
  dkappe1: On another site I am playing a CC GM in a consultation game. Engines allowed.

It's a bunch of sub 2000 players all running their engines -- stockfish, rybka 3 & 4, houdini, hiarcs, etc. -- and voting on moves. Good opening, no blunders, reasonable moves.

We almost always end up going with one of Rybka 4's top 3 moves. And in one game the GM is crushing us. I can guarantee that our Rybka setup is overall more powerful than his (and he's got lots of other ICCF games going, so can't devote his whole machine to our games).

How do you explain this? If we all play the best Rybka moves, we shouldn't be getting blown out, no? Or does the GM have some super secret engine that is so much more powerful than Rybka?

My guess is that some of these chess.com weenies didn't like the fact that Yelena's "Rybka" (i.e. her brain) beat their actual Rybka. :-)

Dec-06-10  bartonlaos: <dkappe1> Well said.

<Zygalski> To pre-screen at Chess.com, you require 20 games, but to show doubt in a court of law, all that's required is 1 game. And you know what? I just rechecked Heather's game at depth 20, and still get 100% for Yelena.

Did it ever bother you that if she was using an engine against these lower-rated opponents, it was just to arrive at a Chess.com rating equivalent to her FIDE correlation had she never used one? How do you answer that question except to conclude that she wasn't actually using an engine in the first place - and, that the batch set was misapplied to inflate her efficiency skewing subsequent analysis against her.

You've really made a fine mess of things.

Dec-06-10  Zygalski: Sounds like smoke & mirrors to me. I didn't ban her - an International Master did. He also had access to other vital information held on the site servers which, combined with massively high engine match correlation, would prove extremely convincing in a case such as this.

Attempting to win internet arguments after the event seems like a bit of a waste of time to me, all things considered & drawing attention to Yelena's chess.com games is foolish if your goal is to act pretty much single-handedly as YD's online guardian angel.

Pushing this topic to the top of the list in kibitz presumably makes more people look at the chess.com games & I very much doubt YD would want that.

Dec-06-10  croco: Well, on another chess site these games were discussed. Yelena showed a nearly perfect play, well above what Kasparov, Fischer or any other CC player before 1980 managed to produce.

http://www.chess.com/echess/game.ht...
http://www.chess.com/echess/game.ht...
http://www.chess.com/echess/game.ht...
http://www.chess.com/echess/game.ht...
http://www.chess.com/echess/game.ht...
http://www.chess.com/echess/game.ht...
http://www.chess.com/echess/game.ht...
http://www.chess.com/echess/game.ht...
http://www.chess.com/echess/game.ht...
http://www.chess.com/echess/game.ht...
http://www.chess.com/echess/game.ht...

Dec-06-10  croco: Of course, no cheating conclusions can be drawn. For instance, I personally believe that, in the sports world, all those doping test are just unfair: maybe there are athletes who, by extensive training, forced their bodies to produce naturally higher levels of testosterone.
Dec-06-10
Premium Chessgames Member
  Annie K.: Guys, don't feed the trolls - getting responses so they can go on and on and ooooooon with their filthy little smear campaign is exactly what they want.
Dec-07-10  bartonlaos: <Annie K.> Absolutely right. He tried passing himself off as a Chess.com authority, but the reality is that he's just a troll, who runs out of ideas and brings in the new members to rehash arguments that have already been laid to rest. The most recent one by you.
Dec-08-10  Zygalski: <bartonlaos>
That's another lie from you.

Please quote where I tried passing myself off as a chess.com authority. I always said that analysis was done by a group of volunteers & then passed to chess.com staff for them to take further if needs be.

You can't win the argument because Dembo remains banned from that site so you resort to cheap smear tactics spinning a web of lies which are based on untruths.

You can't find a single significant inaccuracy in any Dembo chess.com game so as always your tactic is to ignore.

I feel sorry for you. You're a truly sad individual.

If your goal is to further publicise what happened to the Yelena Dembo account on chess.com then well done - you've succeeded! I hope people analyse her games there with Rybka & draw their own conclusions :)

Dec-08-10
Premium Chessgames Member
  whiteshark: <Annie K.> Wize werdz frum wite kitteh.
Feb-06-11  Lenks: Chess.com was extremely slow at banning blatant cheaters and continues to be so today. It was certainly to Mrs. Dembo's misfortune that she was caught even though her cheating was so entirely obvious. I'm amazed at her supporters. I'm sure you like her personality, but why not look at her games and the evidence before making yourselves look like idiots for not knowing how badly she cheated.
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