<In round 7, So won an important theoretical game in the Fianchetto Grunfeld. Developed by the Czech players in the 1960s, the variation is a classic confrontation between the white pawn center and the black light pieces. Both grandmasters, Wesley So and David Navara, played it in the past and we could have expected a new twist. It came on move 13, when So uncorked a new pawn sacrifice recommended by a few chess engines.
1.d4 Nf6 2.c4 g6 3.Nf3 Bg7 4.g3 d5 5.cxd5 Nxd5 6.Bg2 Nb6 7.Nc3 Nc6 (Attacking the center before white castles prevents the advance of the d-pawn. The Czech grandmasters had a lion's share in developing this dynamic variation. The black pieces are holding the white pawn center in check.
8.e3 0-0 9.0-0 Re8 Postponing the e7-e5 strike in the center, black plays a useful, waiting move, discouraging white from developing his dark bishop on the long diagonal. The main idea is 10.b3 e5 11.d5 e4! Kasparov gets lots of credit for playing the rook move.
10.Re1 [10.b3 e5 11.d5? (11.Nxe5 Nxe5 12.dxe5 Qxd1 13.Nxd1 Bxe5 14.Bb2 )
10...a5 11.Qe2 [Carlsen suffered a crushing defeated against Giri, playing 11.Qd2 but the queen was on the wrong spot and the game ended quickly with inexplicable blunders from white: 11...e5 12.d5 Nb4 13.e4 c6 14.a3 cxd5! 15.axb4 axb4 16.Rxa8 bxc3 17.bxc3 Nxa8 18.exd5 Nb6 19.Rd1 e4 20.Ng5 e3 21.Qb2 Qxg5 22.Bxe3 Qg4 0-1 Carlsen,M (2814)-Giri,A (2686)/Wijk aan Zee NED 2011
11...a4 [11...e5 12.Nxe5 Nxe5 13.dxe5 Bxe5 14.e4!? This move gives black more fits:
12.Rd1 Be6?! Diagram [12...Bd7 ]
13.d5! [The computers figured out the dangerous tactics along the d-file and came up with a promising pawn sacrifice. Navara already played 12...Be6 against Laznicka in the Czech Blitz Championship in last December.
13...Nxd5 14.Nb5! [The point! White threatens 15.e4 and because black can't escape from the pin quickly, white gets a bishop pair and creates a double-pawn. White can't utilize the pin immediately with 14.Nxd5 Bxd5 15.e4 since black has 15...Bc4! 16.Qc2 Nb4! winning.]
14...Qc8 15.Ng5 Rd8 16.Nxe6 fxe6 17.Rb1 Preparing to develop the dark bishop, white is slightly better.
17...Kh8 Anticipating a hit from e6, Navara removes his king. The alternatives include some knight moves. [17...Nb6 18.Bd2 Ne5 19.Bc3 Rxd1+ 20.Rxd1 c6 21.Bxe5 Bxe5 22.Nd4 Bxd4 23.exd4 Nd5 24.Bh3 Kf7 25.Re1 Nc7 ; 17...Ne5 18.e4 Nb6 19.Rxd8+ Qxd8 20.Bg5 ; Deep Rybka 4 recommends to retreat 17...Nf6 18.Bd2 Ne5 (18...Ne8 19.f4 Nd6= ) ]
18.Bh3 Interestingly, So refrains from the move e3-e4 that weakens the square d4.
18...Nf6 19.Bd2 Ra6
20.Bc3 Whire's bishop pair has black's position in crossfire.
20...Rd5 21.Rxd5 Nxd5 22.Bxg7+ [Removing the defender is preferable to keeping the bishop pair. 22.Be1 ]
22...Kxg7 23.Qc4 Threatening to win a piece with 24.Qxd5
23...Nf6 24.Rd1! [24.Bxe6 Ne5 25.Bxc8 Nxc4 eases black's defense.]
24...Kf7 25.Qf4!? [Stronger than going into a slightly better endgame after 25.Bxe6+ Qxe6 26.Qxe6+ Kxe6 27.Nxc7+ Ke5 28.Nxa6 bxa6 ]
25...Rb6 [25...Ra5 26.Qxc7 Qxc7 27.Nxc7 ]
26.Qxa4 Ne5 27.Nd4 c5 28.Qc2! The pin allows white to protect the b-pawn.
28...Rd6 29.f4!? Taking advantage of the unstable black horse.
29...Neg4 [The knight will be vulnerable, but after 29...Ned7 30.Nxe6 white is a healthy pawn up since 30...Rxe6 31.Bxe6+ Kxe6 loses to 32.Qc4+ Kf5 33.e4+! Nxe4 (33...Kg4 34.Qe6+ Kf3 35.Rd3+ Ke2 36.Qb3 Nxe4 37.Qd1# ) 34.Qd5+ ; After 29...Nc6 30.Qxc5 white should win,]
30.Re1 b6 [30...Kg7 31.Nf3 ]
31.Nf3 Qd7? [Stepping into a fork, black loses a piece. After 31...Rd8 32.Qb3 , threatening 33.Ng5+ and 33.Qxb6, white wins a pawn.]
32.Bxg4 Nxg4 33.h3 Winning a piece.
33...Nxe3 [33...Nf6 34.Ne5+ ]