Anand, Kramnik and missed opportunities

After two more rounds (I wrote my last post after round 2), Vishy Anand and Vladimir Kramnik still share the lead in Mexico City. But they both missed a good opportunity to strengthen their leadership in round 4. Anand won a pawn with Black against Morozevich. His position remained more or less winning for a long time, but he missed several favourable possibilities (the last one at move 56, when he played 56...Re8? instead of the natural 56...Rd2). Even in the moment when he forced a draw by repetition, White was still far from equality, but Vishy was probably a bit tired. Kramnik once again proved his excellent home preparation against Grischuk. Later, he converted his slight advantage into a decisive one, but during his opponent's time trouble transposed to an endgame (by playing 38.Rxa7? instead of 38.Qc2) which offered him only slim chances for success. Grischuk defended accurately and obtained a draw. In the meantime, Morozevich and Aronian has won their first game, against Peter Svidler (round 3) and Peter Leko respectively (round 4), and they now share the third place on 2/4 with Grischuk and Boris Gelfand, while the two Peters follow on 1.5. Anything can still happen.
The official site of the competition is http://www.chessmexico.com/; you can also find photos (by Cathy Rogers), results and download/reply games on my Italian site, www.messaggeroscacchi.it (link to the WCC page is http://www.messaggeroscacchi.it/mondo/mondiale07.html).
And now here is an annotated game from round 2...

Aronian,L (2750) - Anand,V (2792) [D43], Mexico City 14.9.2007
1.d4 Nf6 2.c4 e6 3.Nf3 d5 4.Nc3 c6 5.Bg5 h6 6.Bh4
In case of 6.Bxf6 (as played just one day earlier in Kramnik-Svidler), play takes a positional course.
6...dxc4 7.e4 g5
An extremely sharp line. 7...b5 8.e5 g5 9.Nxg5 hxg5 10.Bxg5 Nbd7 has been tried by all top players in past 10 years, with various success.
8.Bg3 b5 9.Ne5 h5 10.h4 g4
Black is a pawn up, but White has a strong centre and better prospects of transferring his king to a safe location.
11.Be2 Bb7 12.0–0 Nbd7 13.Qc2 Nxe5 14.Bxe5 Bg7 15.Rad1 0–0 16.Bg3 Nd7 17.f3
White finally establishes a centre of pawn tension and aims to open the f-file for his king's rook. But Vishy has an unpleasant surprise...
17...c5!?
After his win Anand said: "The game revolved around this move 17...c5. It's a very interesting idea. We found it just here - Nielsen suggested it about three days ago. Sometimes if you can surprise your opponent it is worth almost as much as making a lot of good moves, because he has to deal with a lot of problems over the board". Previously, 17...Qb6 was considered best.
18.dxc5
18.d5 can be strongly met by 18...Bd4+ 19.Kh2 (19.Kh1 Be5 20.f4 Bxc3 21.bxc3 exd5 22.exd5 Re8 -/+) 19...Be5 20.f4 Bxc3 21.bxc3 exd5 22.exd5 Qf6 with strong initiative.
18...Qe7
Key idea behind c5 novelty. White can not play 19.Nxb5?? because of 19...Qxc5+, so Aronian has to find something to keep pace with his opponent.
19.Kh1?
Not a brave move indeed. 19.Bd6?! was too risky, e.g.: 19...Qxh4 20.fxg4 Be5! 21.Bxe5 Nxe5 22.gxh5 b4 23.Nb5 Bxe4 24.Qc1 Bxg2 25.Kxg2 Kh7 26.Rf4 Rg8+ 27.Kf1 Qh2 28.Ke1 Rg2 and Black wins; but 19.a4 was an alternative to be considered: after 19...b4 (19...a6!?) 20.Nb5 Qxc5+ 21.Bf2 Qe7 22.Qxc4 gxf3 23.gxf3 the position is unclear, but chances look about equal.
19...a6 20.a4 Bc6
Black has stabilized the position and threatens to win the c5-pawn with ... Nxc5. Since 21.Rd6 can be strongly met by 21...Be5!, White is forced to resort to radical measures.
21.Nd5
After the game Aronian was critical of this move, but it doesn't look he has better alternatives.
21...exd5 22.exd5
Normally, this kind of operation would yield White an advantage...
22...Be5!
...but White's king is unsafe and Vishy forces his opponent to release the kingside tension and consolidates his advantage.
23.f4
23.Bxe5? loses because of 23...Qxh4+! 24. Kg1 Nxe5 25.fxg4 Nxg4 26. Bxg4 hxg4 and Black has a winning position. Also 23.Be1? loses because of 23...g3!, so it seems that 23. f4 is forced.
23...Bg7
"He played 21.Nd5 fairly quickly", said Anand after the game, "and I think he missed this plan of 22...Be5 and 23...Bg7, or he underestimated it. As you can see, in the whole game I am playing against this bishop on e2 - my pawns on h5 and g4, and b5 and c4 control this bishop. This turned out to be the deciding factor in the game".
24.dxc6 Nxc5
Both White's bishops are very passive.
25.Rd5?!
But this is not the way to play for a counterplay! 25.Qf5!? comes into consideration, e.g.: 25...Nxa4 26.Rfe1 Qc5 27.Rd5 Qxc6 28.Qxh5 Qg6 29.Qxg6 fxg6 30.Bxg4 Nxb2 31.Re7 and Black has winning chances, but White gets some active play at least.
25...Ne4 26.Be1 Qe6
Very powerful choice by Anand.
27.Rxh5?!
White has temporarily won a pawn, but his rook is miserably placed. 27.Qd1 Qxc6 28.b3 Rfe8 29.Rxh5 is probably more precise, although Black is better anyway.
27...f5
27...Qg6 was a good move as well, e.g.: 28.f5 Qxh5 29.Qxe4 Rfe8 30.Qc2 Be5 31.g3 Bc7 32.Bf2 Qh6 33.Bxg4 Qxc6+ 34.Kh2 Rad8 35.axb5 axb5 and Black must win.
28.Kh2 Rac8 29.Bb4 Rfe8 30.axb5
White doesn't have a good defence. After 30.Bd1 Qf7 31.Rg5 Rxc6 32.g3 Rce6 33.axb5 axb5 Black is winning anyway.
30...axb5 31.Re1 Qf7 32.Rg5 Nxg5 33.fxg5 Rxc6 34.Bf1 Rxe1 35.Bxe1 Re6 36.Bc3 Qc7+ 37.g3 Re3
Black's position is now completely winning.
38.Qg2 Bxc3 39.bxc3 f4 40.Qa8+ Kg7 41.Qa6 fxg3+ 0–1