let me show you two of the clearer ones, then:

1) the move sequence 29 to 32

black could have played: 29... Qxa2 after which black is two pawns up with white only having slight compensation for one of them. play might continue 30. Kg1 Qe2 31. h3 Bg8 32. Rd8 Qe3 33. Kh2 (there's nothing better) Qf4+ 34. Qxf4 exf4 and black's simply winning:

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instead play continued 29... Qe2!? 30. h3 h6?! (snatching the 2nd pawn with Bxa2 is still better) 31. Kh2 and now the lemon 31... Qe3? and white draws with 32. Rd6! which wins back the pawn:

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so, from a winning position on move 29 to a very drawish one 3 moves later. to me that's a clear case of a "missed opportunity".

after 32. Rd6! black doesn't have anything better than 32... Qf4+ (or 32... Qg5, or moves that lead to immediate repetition and draw) due to white's threat of Rxe6 follwed by Qd8+ and picking up the rook with the next check. after 32... Qf4+ 33. exf4 exf4 34. Nd3 we've reached a very drawish end game (black's f-pawn drops in the very next moves).

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2) move 36, where it looks like ivanchuk simply forgot to exchange on e4 first:

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instead of 36... Bxa2?! as played, black wins comfortably with 36... Qxe4 37. Nxe4 <Bxa2> 38. Re8 a5! 39. Ra8 b6 40. Ra6 Rf7! 41. Rxb6 Bd5 42. Nd6 Rf2+ etc. eating white's remaining pawns and heading for a winning R+2P versus R ending:

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in addition to being practically won, the ending is much easier to play for black <without> the queens on. as we saw in the game, anand could keep making things difficult for ivanchuk due to the white queen and the possibility for perpetuals (or even mate cheepos if black became really careless).

uhm, no. he gave up his entire advantage at least a couple of times, but anand failed to exploit it.

< If you mean Rybka/Houdini's eval shifted by 0.20 in White's favour when Black played a slightly inferior queen move, I would hardly call that an opportunity.>

no, i'm talking result-changing errors, like the two series of moves pointed out above - which both turned a win to a draw (from ivanchuk's point of view), and a loss to a draw to a loss (from anand's, when he got and then failed to take advantage of the opportunity).

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here 40... Kg8 seems to win for black, while after the played 40... Kg7? white has active options (the game continued 41. Nd3?! which is natural but which probably loses). instead the following is very interesting:

41. Qe5+ Qf6 42. Qc7+ Qg6 43. Nd3!

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white is now much more active than after the slightly passive 41. Nd3?! and we can consider one line that emphasize the importance of "fast pawns" compared to "many pawns":

43... Bd5!? 44. c4! Bxc4 45. Ne5+ Kg5 46. Nxc4 Qf2+ 47. Kh1 Qf1+ 48. Kh2 Qxc4

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looking promising for black? less than it seems: 47. Qe5+ Kg6 (Kh4 would be unfortunate ;o) 48. Qh5+ Kg7 49. Qe5+ Kf7 50. Qh5+ Qe7 51. Qh4+ Kd7 52. Qxh6

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black's extra pawn is less important than white's "fast pawn" on g4. compare this position to some of the comfortably winning end games (without queens on) that black could've chosen earlier on. my guess is that the above position would've been drawn (there is no "true answer" available).

It's all time greatest practitioner was the great American champion Marshall.

http://www.chessgames.com/perl/ches...

Both Raja and Marshall have good results with it. Raja has employed it 3x this year alone.

Marshall used it 5x in the famed 1903 Monte Carlo tournament scoring wins against GM caliber players Taubenhaus and Teichmann (who is probably a 2700 player by today's standards). Marshall kept on employing it regularly until 1909, when he lost 3 games with it, one to then reigning US champion Showalter and two to Capablanca, in his 1909 matches with them, after which he stopped playing it against high level opposition. Both Showalter and Capa played the more aggressive 4. Nc3 variation instead of Anand's conservative 4. d3.

Perhaps Anand should have played more aggressively from the beginning instead of see-sawing from a conservative opening option to an unsound middle game attack that fell flat.

Even so, ... Kg8 had the great merit of avoiding check next move so slightly surprising Chuky played Kg7. In these situations I would be guided by the priciple "when in doubt, give check" So again surprising Vishy didnt play Qe5+. These alternative moves for both players seem too obvious to have been overlooked, so maybe they considered and rejected them.

thanks, scormus.

<Yes, there were mistakes on both sides but such was the tension in the position, the player who doesn't slip under the pressure problably isn't human.>

certainly. i simply couldn't agree that anand was not given some opportunities to counter after he first found himself in a losing position. both against aronian in round 4 and anand in round 3 ivanchuk nearly let the win slip. but while aronian only got one chance (due to Rxf7?! where Bc3 or Bc5 was clearly stronger), anand was given several chances to get inside the drawing range.

still, ivanchuk deservedly won both games, of course. it's more a reflexion of the games (in particular the anand one) being far from "flawless". still, i have to admit being impressed with how extremely precisely ivanchuk (and aronian) played for several moves in a pretty crazy middlegame position in round 4. one thing is the complications that actually were played out on the board, another the additional and even "worse" side-lines that didn't materialize.