Tuesday, 20 October 2020

Chess Evolution: QGD Exchange (conclusion)

THE line 1.d4 d5 2.c4 e6 3.Nc3 Nf6 4.cxd5 remains a potent white weapon at all levels, not just, as is sometimes thought, among players below master standard.
There are 71 such games from the most-recent two years in ChessBase's 2020 Mega database, ie 2018-19, in which both players are rated at least 2600. In those games White scores +31+26-14, which is 62%.
The picture is, if anything, even starker for Black in games in the same period in which both players are super-GMs rated at least 2700 - White scores +12=6-6, or 63%.
Here is a game illustrating some of the problems Black faces.
Ivan Cheparinov (2666) - Hao Wang (2725)
Belt And Road Hunan (Changsha, China) 2019
1.d4 Nf6 2.c4 e6 3.Nc3 d5 4.cxd5 exd5 5.Bg5 c6 6.e3 Be7!?
Sometimes Black plays 5...c6 in the hope of inducing 6.Qc2 from White. But if White then plays the straightforward 6.e3, Black is not obliged to play the double-edged 6...Bf5!? 7.Qf3 Bg6 8.Bxf6 etc, and can instead, as here, stick to the main lines.
7.Bd3 Nbd7 8.Nge2 Nf8
This is one of the points of holding off from castling early. The queen's knight will challenge the white dark-square bishop from e6 while simultaneously eyeing the important squares c4 and e4. 
9.0-0 Ne6 10.Bh4 0-0 11.f3
The central pawn-push is White's most-fashionable plan and has been for quite a few years.
11...b6!?
When the result of the game is known (White won), it is easy to blame a move like this as too slow, but that is probably unfair. My main analysis engines Stockfish12 and Komodo11.01 suggest 11...g6 12.Qc2 Re8, while slightly preferring White. Certainly the immediate 11...c5?! 12.dxc5 Bxc5 13.Kh1 does not look appetising for Black (13...Bxe3? runs into 14.Bxf6 gxf6 15.Nxd5! with a strong game for White).
12.Kh1 g6!?
This move, I believe, has two purposes: i) to possibly play the manoeuvre ...Ng7 to support ...Bf5, ii) to cut out Bxh7+ tricks by White, as in the last line in the previous note.
13.Bf2!?
The bishop supports the d4 pawn, making the thrust e4 more likely, and prophylactically evades a bishop-exchange following ...Nh5.
13...c5 14.Qd2
White could give Black hanging pawns with 14.dxc5!? bxc5, but Cheparinov presumably feels his pieces are not as yet well-placed to combat such a duo.
14...Bb7
Pushing on with 14...c4!? is the type of move club players are often warned against, even if, as here, it comes with tempo. After 15.Bc2 Bb7 White can play an immediate 16.e4, after which 16...dxe4 17.fxe4 leaves White with hanging pawns that seem well-supported by the white pieces.
15.Rad1 a6 16.Bc2!?
Now ...c4 will not come with tempo.
16...Re8
The engines prefer 16...Rc8!?, one point being the rook will be well-placed on the c file should White ever play d.xc5.
17.Rfe1
The engines reckon the time is ripe for playing e4.
17...Rc8 18.dxc5!?
Cheparinov decides to play against hanging pawns. He may have felt the time for e4 had passed, eg 18.e4 dxe4 19.fxe4 cxd4 20.Nxd4 Ng4 21.Bg1 Nxd4 22.Bxd4 Qxd4! 23.Qxd4 Bc5 24.Qd2 Nf2+ 25.Qxf2 Bxf2 sees a lot of liquidation, leaving White with an isolated e pawn.
18...bxc5
This is better than accepting an IQP, according to the engines.
19.Ba4 Rf8 20.Bb3 Qb6 21.Nf4!? Nc7?!
After 21...Nxf4 22.exf4 Rfe8 23.Ba4 Bc6 24.Bxc6 Qxc6 25.Nxd5 Nxd5 26.Qxd5 the engines reckon White is slightly better. He has an extra pawn, albeit doubled, and Black has two isolated queenside pawns. Nevertheless that is probably a better try for Black than the passive text.
22.e4!? dxe4
The engines slightly prefer 22...d4, although Black's pawn-duo looks ripe for successful blockading.
23.fxe4 Rcd8 24.Nfd5 Ncxd5 25.exd5
White has an isolated d pawn, but it is a passed pawn and restricts Black's room for manoeuvre. Meanwhile Black has two isolated pawns of his own to worry about.
25...Qc7 26.Bg3 Bd6 27.Bh4 Bf4
Not 27...Be7? 28.d6!
28.Re7! Qd6
Not 28...Qe7? 29.Qxf4.
29.Qe1 Bc8?!
Black's position collapses quickly after this, but White is better after Stockfish12's 29...g5!? 30.Rxb7 Rfe8 31.Qf2 gxh4 32.Qxh4 and Komodo11.01's 29...Rb8 30.Ne4! Nxe4 31.Rxe4 g5 32.Rxf4! Qxf4 33.Bg3.
How should White proceed?
*****
*****
*****
*****
30.Re6! Bxe6
Or 30...fxe6 31.dxe6 Qe7 32.Rxd8 Rxd8 33.Bxf6 Qxf6 34.e7+ Kg7 35.Nd5! Qd6 36.exd8=Q Qxd8 37.Nxf4.
31.dxe6 Qe5
If 31...Qe7 then 32.exf7+ etc.
32.e7 Rxd1 33.exf8=Q+ Kxf8 34.Qxd1 g5 35.Bf2 Bxh2 36.Qe2 Qc7 37.Ne4 Nxe4 38.Qxe4 Kg7 39.Qf5 1-0

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