THERE are almost 37,000 examples in ChessBase's 2020 Mega database of the move 4.cxd5 in the position reached after 1.d4 d5 2.c4 e6 3.Nc3 Nf6 or, less commonly but still popular, after 1.d4 Nf6 2.c4 e6 3.Nc3 d5.
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| Position after 4.cxd5 |
The delayed form, 4.Bg5 Be7 5.cxd5, seems even more modern, first appearing in Mega20 in 1937.
True, other forms of the Exchange Variation have a longer history, for example 4.Bg5 Nbd7 5.cxd5 goes back to at least 1847, and 3.cxd5 to 1844.
But the most-popular modern version of the Exchange with 4.cxd5 is relatively recent, although it has come a long way in 89 years.
A major part of the reason for the move's popularity is its success - White scores 65% in Mega20 with 4.cxd5, but 59% with the more-popular 4.Bg5 and the also-popular 4.Nf3.
In this series I hope to explain why this version of the Queen's Gambit Declined Exchange Variation is so successful by looking at how top players have dealt with it from both sides of the board.
I will start at the beginning with the opening's first example in Mega20.
Mir Sultan Khan - Vera Menchik
Hastings Premier 1931-32
QGD Exchange
1.d4 Nf6 2.c4 e6 3.Nc3 d5
Menchik usually met 1.d4 with 1...Nf6 rather than 1...d5, but rarely continued with a Nimzo-Indian or, after 3.Nf3, a Queen's Indian. Sultan Khan, on the other hand, usually met 1...Nf6 with 2.Nf3, so it seems he had prepared the Exchange Variation especially for this game
4.cxd5 exd5 5.Nf3
The main line today is 5.Bg5, reserving the option of developing the king's knight to e2.
5...c6 6.Qc2
If 6.Bg5, Black can reply 6...Bf5. It is generally considered Black has a very satisfactory game if the light-square bishops are exchanged or if Black is allowed unchallenged control of the b1-h7 diagonal. The text has been played by Kasparov, Kamsky, Ivanchuk and other strong grandmasters.
6...Bd6!?
An aggressive placement for the black dark-square bishop. Kramnik in a 2000 simul preferred 6...Be7, which is the traditional destination of this bishop in the QGD Exchange, while Botvinnik and Kasparov tried 6...Na6!?
7.e3!?
Shutting in the white dark-square bishop is unusual. Most players in this position have preferred 7.Bg5.
7...Nbd7 8.Bd3 0-0 9.Bd2 Re8 10.h4!?
Sultan Khan intends castling long, an idea that Kasparov later revived in the QGD Exchange.
10...Nf8 11.0-0-0 b5
Positions with opposite-side castling can be particularly difficult to assess. Here my main analysis engines, Stockfish12 and Komodo11.01, disagree - Stockfish12 gives Black a clear advantage while Komodo11.01 reckons the chances are equal.
12.Ng5 a5 13.e4 b4 14.Na4!?
Sticking a white knight on a4 in response to the move ...b4 is often an effective way of slowing Black's queenside attack.
14...dxe4 15.Nxe4 Nxe4 16.Bxe4 Be6 17.Kb1
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| How should Black proceed? |
*****
*****
*****
*****
17...b3!
A pawn sacrifice that makes it clear whose king is the more vulnerable.
18.axb3 Rb8 19.Nc5?!
The engines reckon White had to try 19.Qd3!?, eg 19...Bxb3 20.Bxc6 Bxd1 21.Rxd1, when White has the bishop-pair and a pawn for the exchange.
19...Bxc5 20.Qxc5 Bxb3
The engines' 20...Rb5!? is also strong.
21.Rde1 Ne6
Black emerges with an initiative, while White's pieces are a little uncoordinated, eg the king's rook is basically not in the game.
22.Qc3
The engines prefer 22.Qxa5!? but reckon Black is much better after 22...Qd7.
22...Qxd4?!
Black wins a pawn, but allowing White to get queens off is a major concession. The engines reckon Black does much better opening more lines to the white king with 22...c5!?
23.Qxd4 Nxd4 24.f3
Not 24.Bxa5? Rxe4! 25.Rxe4 Bc2+ and 26...Bxe4. However, according to the engines, 24.Bd3!? keeps White's disadvantage to a minimum.
24...a4 25.Bf4 Rbc8 26.Bd3 Ne6 27.Be5 c5 28.Bb5 Red8 29.Re4 Nd4 30.Bxd4 cxd4 31.Bd3
Sultan Khan pins his hopes on blockading Black's extra pawn, but it is hard to believe it is enough to save the game.
31...Rb8 32.Ka1 Rb4 33.Rhe1 Be6 34.Re5 a3!
Further exposing the white king.
35.b3
Even worse is 35.bxa3? Ra8.
35...Rxb3 36.Bc4 Rb2 37.Bxe6 fxe6 38.Ra5 d3 39.Rxa3 d2 40.Rd1 Rc2 0-1
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