Are computers destroying chess? These days I have been watching the candidates tournament, and I couldn't avoid noticing that players are reeling/scared of computer home preparation "a little bit too much".

For example: 

1) In the game Anand vs Kramnik (round 4), Kramnik at the move 22 just played the "incredible" move Nd4 (home computer preparation), giving the Knight for "free" without any apparent compensation, four moves later we end up understanding  that Nd4 just forces a draw:

[FEN ""]
[Event "FIDE Candidates 2014"]
[Site "Khanty-Mansiysk RUS"]
[Date "2014.03.17"]
[Round "4.2"]
[White "Anand, Viswanathan"]
[Black "Kramnik, Vladimir"]
[Result "1/2-1/2"]
[WhiteTitle "GM"]
[BlackTitle "GM"]
[WhiteElo "2770"]
[BlackElo "2787"]
[ECO "D37"]
[Opening "QGD"]
[Variation "4.Nf3"]
[WhiteFideId "5000017"]
[BlackFideId "4101588"]
[EventDate "2014.03.13"]
[StartPly "43"]

1. d4 Nf6 2. c4 e6 3. Nf3 d5 4. Nc3 dxc4 5. e4 Bb4 6. Bg5 c5 7. Bxc4 cxd4 8. Nxd4 Bxc3+ 9. bxc3 Qa5 10. Bb5+ Nbd7 11. Bxf6 Qxc3+ 12. Kf1 gxf6 13. h4 a6 14. Rh3 Qb4 15. Be2 Ne5 16. h5 Qd6 17. Qd2 Nc6 18. Rd3 Qh2 19. f4 Rg8 20. Bf3 Bd7 21. Ne2 Qh1+ 22. Ng1 Nd4 23. Rxd4 Bb5+ 24. Kf2 Qh4+ 25. Ke3 e5 26. fxe5 Qg5+ 27. Kf2 Qg3+ 28. Ke3 Qg5+ 29. Kf2 Qg3+ 30. Ke3 Qg5+ 1/2-1/2


2) Topalov vs Kramnik (round 6). Kramnik at the end of the game, in the press conference, was "whining" that he lost the game because Topalov had prepared all in home with a computer, almost like suggesting that he lost to a computer:

[FEN ""]
[Event "FIDE Candidates 2014"]
[Site "Khanty-Mansiysk RUS"]
[Date "2014.03.19"]
[Round "6.1"]
[White "Topalov, Veselin"]
[Black "Kramnik, Vladimir"]
[Result "1-0"]
[WhiteTitle "GM"]
[BlackTitle "GM"]
[WhiteElo "2785"]
[BlackElo "2787"]
[ECO "D37"]
[Opening "QGD"]
[Variation "classical variation (5.Bf4)"]
[WhiteFideId "2900084"]
[BlackFideId "4101588"]
[EventDate "2014.03.13"]

1. d4 Nf6 2. c4 e6 3. Nf3 d5 4. Nc3 Be7 5. Bf4 O-O 6. e3 Nbd7 7. c5 Nh5 8. Be5
c6 9. Bd3 g6 10. h4 f5 11. Bh2 b6 12. b4 f4 13. O-O a5 14. b5 bxc5 15. bxc6 Nb8
16. Bb5 Ba6 17. a4 Qc8 18. dxc5 Nxc6 19. Nxd5 exd5 20. Qxd5+ Kh8 21. Qxc6 Qxc6
22. Bxc6 Rac8 23. Bb5 Bxb5 24. axb5 Bxc5 25. Rxa5 fxe3 26. fxe3 Bxe3+ 27. Kh1
Rc2 28. Rb1 Rfc8 29. Raa1 Bb6 30. Be5+ Kg8 31. Ra6 Be3 32. b6 Rc1+ 33. Rxc1
Rxc1+ 34. Kh2 Rb1 35. g4 Bf4+ 36. Kg2 Bxe5 37. Nxe5 Nf4+ 38. Kf3 Ne6 39. b7 Rb3+
40. Kf2 Rb2+ 41. Ke3 1-0


So, looks like nowadays high-level chess players have to take in consideration when analyzing variations during the game, that some of that variations may be had been analyzed beforehand by his opponent with the help of the computer.

For a fan o chess as I, this computer home preparation takes all the fun of the game, because when for example Tal sacrificed a piece, was awesome because he had to think about it over the board, or at least it was human home preparation. Nowadays, if a player sacrifices a piece on the opening, people will most likely thing that this sacrifice was home computer preparation, so it is not awesome anymore. Looks like the game is becoming more about memorizing sequences of moves. 

My question is:

It is true the engines have level up the game, but can we also conclude that engines at a certain level are destroying the human cognitive process or figuring out moves by them selfs over the board (mainly at opening phase)?

How can someone play the game in a way that he can avoid computer home preparation?

Thanks.
My short answer: no, computers are not destroying chess. And now here comes a really long version ...

Your first question:


  It is true the engines have level up the game, but can we also conclude that engines at a certain level are destroying the human cognitive process of figuring out moves by themselves over the board (mainly at opening phase)?


As indicated above, in a word, I'd say no. In more words, I don't think there's anything particular to engines about the phenomenon you describe, and the "problem" of preparation, to whatever degree it exists, is really just about the single, well-analyzed starting position of chess. Chess960 (as alluded to in Fischer's earlier answer) tries to address that latter concern, as did things like Capablanca Chess well before that. When Capablanca thought that chess theory was all played out already in the 1920s, it certainly wasn't because of the chess engines of his day (and he also happened to be quite premature in his assessment).

Yes, engines raise the quality of players' home preparation these days and can do a lot of heavy lifting, but still the engines are just tools which strong players use to aid their creative opening endeavors. Consider this: even if you were to have as fantastic a chess memory as, say, Kramnik, so that you could efficiently memorize a ton of engine-aided preparation, if you don't also have Kramnik's all-around understanding of the game and what to aim for out of the opening, the preparation he has memorized will far outshine yours, not necessarily in the quality of the individual moves, but certainly as regards the body of lines he has chosen to learn. (And of course, there will still basically always come a point in the game where the preparation is left, and Kramnik will certainly start crushing you then.) Some players are stronger than others, and that sort of strength still applies to engine-aided preparation.

Again, there is nothing special about engines here. The same was true of preparation in eras where it was aided only by books and periodicals; then too games were sometimes won simply from superior opening preparation. Here is a game from 1935 in which Botvinnik does just that, and which GM Kavalek references in a recent article on the sixth world champion:

[fen ""]
[White "Mikhail Botvinnik"]
[Black "Rudolf Spielmann"]
[Event "Moscow 1935"]

1.c4 c6 2.e4 d5 3.exd5 cxd5 4.d4 Nf6 5.Nc3 Nc6 6.Bg5 Qb6?! 7.cxd5! Qxb2? 8.Rc1! Nb4 9.Na4 Qxa2 10.Bc4 Bg4 11.Nf3 Bxf3 12.gxf3 1-0


As Kavalek notes, Spielmann had played the white side of this line up through move 6 the previous year, though in that game he played the weaker response 7.c5?!:


  [The aggressive move 6...Qb6?!] was recommended by the Czech master Karel Opocensky in his chess column in Narodni politika and it was used for the first time by Josef Rejfir against Spielmann in Maribor 1934. 'Surprising and good,' wrote Rejfir in Ceskoslovensky Sach 8-9/1934 about Opocensky's invention. The Wiener Schachzeitung called it the Prague variation.


So Spielmann was certainly familiar with this line when he chose to go into with the black pieces. But Botvinnik was also familiar with the earlier game, and he managed to analyze a bit deeper than had been done before, which netted him a win out of the opening. That sort of thing happened before engines, and sometimes happens with them today. Still, in the preparation itself, as well as playing the games once out of preparation of course, the skill and creativity that chess has always demanded is squarely on display.

Given what I've written above, my response to your other question is probably pretty predictable.


  How can someone play the game in a way that he can avoid computer home preparation?


Just try and end up in a line that your opponent hasn't analyzed. But again, I would stress that there is nothing particular to computer home preparation here; it's the same problem it has always been. If I'm Rudolf Spielmann, and I recently got burned by Botvinnik's home preparation (without engines of course), then if I want to avoid the same fate next time we play I need to try and steer the game to lines where Botvinnik won't have had the chance to out-analyze me ahead of time. Maybe I'll be successful, maybe I won't, but the challenge was the same in the era of books as it still is in the era of engines.