1.Nf3
d5
2.d4
Nf6
3.c4
c6
4.Nc3
a6
The Chebanenko Variation. Frankly speaking, I cannot understand why he classical players of the early 20th century could not find this useful move, keeping the possibility of actively developing the traditional problem child bishop on c8. Nowadays, the move seems so logical and natural!
5.a4
One of many sensible replies. What hasn't White tried, in an effort to refute the Chebanenko! Yet even the greatest sceptics have to acknowledge that Black's play has a healthy positional basis. The text move prevents Black gaining space on the queenside by b5.
5...e6
A solid response. True, the bishop on c8 remains passive after all, but White has had to pay for this achievement by weakening the square b4. [The drawbacks of 5...Bf5
6.Qb3
Ra7
7.a5
were revealed in the game Gelfand-Morozevich, Astana 200: 7...e6
(7...dxc4
is more reliable) 8.Qb6!
Qxb6
9.axb6
Ra8
10.c5
Nbd7
11.e3
Be7
12.Be2
0-0
13.Nd2
e5
14.0-0
Rfe8
15.Nb3
Bf8
16.Bd2
Bc2
17.Na5
and White's pressure on the queenside was overwhelming.]
6.g3
Magnus heads for a Catalan set-up. [The latest tests show that after 6.Bg5
Nbd7
7.a5
(7.e3
Qa5!
) 7...h6
8.Bh4
dxc4
9.e3
b5!
10.axb6
Nxb6
11.Ne5
c5
Black successfully equalizes.]
6...a5
Securing a favourable queenside pawn structure. The black pieces will feel comfortable on the b4 square.
7.Bg2
Nbd7
[A rare plan. Usually, Black directs the knight to b4 via a6, eg. 7...Na6
8.0-0
Be7
9.b3
0-0
10.Bb2
b6
11.Ne5
Nb4
12.e4
Ba6
13.Re1
Rc8
14.Rc1
dxc4
15.Nxc4
Bxc4
16.bxc4
e5!
and Black took over the dark squares in the centre (Ruck-Rustemov, Warsaw 2005).]
8.0-0
[A novelty. In most cases, once Nbd7 has bene played, White has to defend the c4 pawn, but Magnus is ready to sacrifice it. 8.Nd2
Be7
9.e4
dxe4
10.Ndxe4
0-0
11.0-0
Nxe4
12.Nxe4
Nf6
13.Be3
Qc7
14.Qb3
Ng4
15.Bf4
e5
16.dxe5
Nxe5
17.Qc3
f6
18.c5
and White was better (Pham Hoang - Le Quang, Vietnam 2003). However, Black's play can easily be strengthened, eg. it would be interseting to try 9...c5!]
8...Bb4
[So this is why the b4 square was left free. 8...dxc4
9.e4
Bb4
10.Qe2
Nb6
11.Bf4
Black will have to suffer for a long time in a passive position.]
9.e4
[A sharp reply! Carlsen opens the centre at once, exploiting Black's slight lag in development. 9.Nd2
]
9...Bxc3
[The most principled. less convincing is 9...Nxe4
10.Nxe4
dxe4
11.Ng5
and now 11...f5?
is impossible because of 12.Nxe6
; Also 9...0-0
allows White pressure after 10.e5
]
10.bxc3
Nxe4
[Worse is 10...dxe4
11.Ng5
and White regains the pawn at once.]
11.Ba3!
Having said "a", White must say "b". He needs to create threats, not worrying about the c3 pawn. Carlsen cuts off the enemy king in the centre.
11...Ndf6
[Kamsky does not grab the second pawn. After 11...Nxc3
12.Qb3
Ne4
13.Rfe1
White certainly has very strong pressure. One cooperative variation runs 13...b6?
14.cxd5
cxd5
15.Nd2
Nxd2
16.Qxd5
Ra7
17.Rxe6+!
mating.]
12.Ne5
White must proceed energetically.
12...Nd6
Kamsky's idea is simple - he closes the a3-f8 diagonal, and so prepares castling.
13.cxd5
exd5
14.c4
Still trying to open central lines at all cost.
14...0-0
Kamsky does not even look at taking the pawn. The safety of the black king is worth all the pawns in the world.
15.cxd5
Nxd5
White has compensation for the pawn.
16.Bxd5
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