CHESS STRENGTH : A Comparison Between Correspondence Chess and OTB Chess

CHESS STRENGTH : A Comparison Between Correspondence Chess and OTB Chess 

              Before we begin to evaluate the comparison of various chess rating values, we have to make an important point. Rating is obtained as a result of games played by chess players. The point I am trying to make is that it doesn't say anything explicitly about the strength of the player or the played game. For example if you take a thousand players with a rating of 2000 and make them play amongst themselves some of the players' ratings can reach 2700.
                We can make two types of comparisons. We can either compare the ratings or the games of the players at the time they were playing OTB or correspondence chess. We won't do the rating comparison because it is quantitative and unnecessary. The reason behind this is that although the FIDE and ICCF ratings of players may be different this is something that may vary according to the character of the player.  While some players are good at fast games the others may close the gap as the thinking time increases. This is something decided in great proportion by the character specialties of a given player. Players with the highest rating in Correspondence chess may only reach 2200-2400 level in OTB chess. However the rating score of Rafael D. Leitao ( a Grand Master in both ICCF and FIDE)  is very  close to each other.  From this we can derive that a player will get a higher rating in the area which he is more inclined to. In fact the correspondence performance of OTB players has always been a matter of curiosity.  Oosterom who is a very strong GM acquired a very strong performance for a while.
                On the other hand rating doesn't say anything about the game that has been played. It is only interested with the score of the game. For example the national rating and the international rating of a player is usually different.
                There is an experiment where a player plays correspondence chess without interfering with the moves of the computer. ( http://chessok.com/?p=24526 ) . Here we see a 2386 rating performance. Considering the technological possibilities   that are available today we can surmise that this performance rating can be increased up to the 2400s. From this point on the rating can only increase by the interference of a human with exceptional positional evaluation ability. We are still in an era where human intervention can improve or change the course of the game. One of the best games that demonstrates the power of correspondence chess and human intervention is the Chytilek-Langeveld game. ( http://chessactive.blogspot.com/2013/01/the-mysterious-chytilek-langeveld-game.html ). In this game there are some moves that the computer could not find. And this is in spite of the PC finding Langeveld's moves after a certain depth. For example Chytilek's move 13. Ng5! couldn't be found even at 31st depth.
                We can say that the rating level of OTB games has increased by 100 points relative to the time when Karpov-Kasparov World Title match was being played. This rating increase is related to the increase of players with high rating.
                We have to add that in some OTB games we encounter 'home preparation' moves which are equal in strength with strong correspondence moves. Home preparation moves are similar to human intervention moves in correspondence chess. The  Nf7 move in the game Topalov – Kramnik game ( http://www.chessgames.com/perl/chessgame?gid=1482320   ) is a very good example to this. The second example is (   http://www.tatasteelchess.com/tournament/livegames )
 the  Aronian –Anand game in the Tata Steel Chess Tournament. These two parties include moves that can only be found in strong correspondence games.  Instead of trying to figure out a rating we can say that the game comprises moves that are above 3000 rating level.
  Another thing is that a correspondence player rarely completes the opening stage of a game poorly because he has access to very many databases that are available.  When you look at the games at the Tata Steel Chess Tournament “Tata Steel Chess 2013” (http://www.tatasteelchess.com/tournament/livegames) in a 2700 rating average game we can find at least one big mistake with analysis by Houdini x64. But when the rating average increases to 2800 the mistake rate decreases more that the rating difference indicates.
The rating that CEGT gives to the strongest engine Houdini 3 in 40/120 games is 3042 http://www.husvankempen.de/nunn//40120new/40_120_ratinglist/40_120_AllVersion/rangliste.html . Under the light of all this information we can come up with a table like the one below.

In this chart red bars represent OTB chess and the blue bars represent correspondence chess. As you can see clearly a 3000 rating level  game of OTB chess has the same strength with rating of a 2400 level game in correspondence chess. Aronian - Anand game and Topalov - Kramnik game reach around 3000 rating level of OTB chess.

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The Mysterious Chytilek-Langeveld Game. (Heemsoth Memorial email 2008)

Chytilek, Roman vs. Langeveld, Ron AH

Heemsoth Memorial email 2008

This mysterious game which you may not be able to find in any ordinary database achieved the Beauty Prize of the tournament. We were amazed to find out that it escaped our attention and did not exist in our database. So we checked and double checked, and at the end a friend sent us the game in text format which we carried into PGN. It was a category 16 tournament, a very strong one (In fact the strongest tournament in ICCF history). On the iccf  web site there was a special page where we were supposed to find the game with Chytilek's comments. However the web page contained only the first two moves with a note that said that the rest of the story will be supplemented. http://kszgk.com/iccf/?page_id=2679
Another mysterious part of the game is that after the game (and the tournament) we don't see R. Chytilek around anymore. While R. Langeveld went on to win the 26th World CC title, we only see a few OTB games from Chytilek. What's more at the iccf tournament crosstable link (http://www.iccf-webchess.com/EventCrossTable.aspx?id=13481) the 'GET PGN' link is absent. The game was also important because if Lamgeveld had won the game he would also have won the tournament.
After narrating all this maybe someone who knows a little bir more than we do can comment about this game and its players.

[Event "Heemsoth Memorial email"]
[Site "ICCF email"]
[Date "2008.??.??"]
[Round "?"]
[White "Chytilek, Roman"]
[Black "Langeveld, Ron AH"]
[Result "1-0"]
[ECO "D27"]
[WhiteElo "2663"]
[BlackElo "2692"]

1. d4 d5 2. c4 dxc4 3. Nf3 Nf6 4. e3 e6 5. Bxc4 c5 6. O-O a6 7. Bb3 b5 8. a4 b4
9. e4!! +=

According to the Chess Active Queen's Gambit Accepted Database this move was first played in 1997 in Koge Open, between Hillarp-Yakovich (0-1).

9.e4!! Bb7

( 9...Nxe4 10.d5! +/- Because of this move Nxe4 isn't advisable. )
10. e5 Ne4 11. Nbd2 Nxd2 12. Bxd2 cxd4

It only seems that Black is a pawn up.  

13. Ng5!  Chytilek attacks early because of the absence of the Knight on f6.

13. Ng5! Be7 14. Qh5 Bxg5 15.Bxg5 Qd7 16. Rac1

White has obtained an ideal position by placing his rooks on c1 and d1. And because of Bg5 and Rc1 Black cannot escape with 0-0-0.
16. Rac1 Nc6 17. Rfd1 h6 18. Be3 Rd8 19. Qg4 g6 20.a5!!

After preventing castling on the Queen's side Chytilek prevents castling on the King's side.

20. a5!! Qe7

( 20...Nxa5 21.Rxd4 White is definitely bettter. ) 
 21. Bd2 Nxa5
Giving up the hope on castling on the King's side also, Black tries to grab a few pawns.
22. Ba4+ Kf8 23. h4!

King's side attack can now begin.
23. h4!  Kg7 24. h5 Rc8 25. hxg6 fxg6 26. Bc2 Qf7 27. Bxb4 Nc6 28. Bd6 Rhd8 29. Be4!

Black is nearly in partial zugzwang.

29. Be4! Na5 30. Bxb7 Nxb7 31. Qxd4 a5 32. Rc3!

A very strong move. Black Rook cannot be exchanged due to the march of the c3 pawn to c4 and c5 and so on.

32. Rc3! Kh7 33. Rf3 Qg7 34. Rf6 Nxd6 35. exd6 Rf8 36. Rxe6 Qxd4 37. Rxd4 Rf7 38. d7

Now the Black side will try to bring the King into play and grab the d7 pawn, while the White side will try to get at least 2 pawns in return.

 38. d7 Rd8 39. Red6 Kg7 40. f3 Re7 41. b3 Re3 42. Rc4 Kf7 43. Rc8 Ke7 44. Rxg6 Kxd7 45. Rc5
( 45...Rxb3 Rxa5 wins easily. )
45. Rc5 Ra8 46. Rb5 a4 47. bxa4 Rxa4

After Rxh6 White will queen his 2 united passed pawns.