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I am a keen player of d4 as white. One of the things that I often read is that the exchange variation of the Queens Gambit Declined is generally considered good for white:

[fen ""]
1. d4 d5 2. c4 e6 3. Nc3 Nf6 4. cxd5 exd5

But the exchange variation of the Slav (or exchanging after Nc3 in the Slav) is considered better for black:

[fen ""]
1. d4 d5 2. c4 c6 3.cxd5 (3. Nc3 Nf6 4. cxd5 cxd5) 3...cxd5

I checked http://www.chessgames.com/perl/explorer and it seems to support this view, with the following win/draw/lose statistics for white for the above variations:

  • QGD All Variations: (41%, 37.7%,21.3%)
  • QGD Exchange: (49.8%,35.3%,14.9%)
  • Slav All Variations: (37.8%, 41.3%, 20.9%)
  • Slav (early exchange): (22.5%,55.2%,22.3%)
  • Slav (exchange after Nc3): (30.2%,49.9%,19.9%)

So it seems clear that the exchange of central pawns favours white in the QGD, but favours black in the Slav.

My question is simply - why? The resulting positions are superfluously similar (in the Slav black is missing the c-pawn, while in the QGD the e-pawn), yet positionally these must be very different! Is there a simple explanation of why this is the case? Would a clever newbie (i.e. somebody who plays chess very well, but have never played these variations) be able to make this deduction over the board through pure reasoning, or is this the type of thing you can only deduce by studying the opening theory?

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  • You mean QGD (Queen's Gambit Declined), not QGA.
    – Dag Oskar Madsen
    Oct 24, 2013 at 13:14
  • Thanks Dag, yes you are very right. I have edited the question to reflect that.
    – firtydank
    Oct 24, 2013 at 13:26
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    Note that after 1. d4 d5 2. c4 e6 3. Nc3, grandmasters usually play 3...Be7 because it takes the sting out of 4. cxd5. So part of the answer to your question is that you're working with a move order for black that is considered slightly susceptible to an early cxd5.
    – Nate
    Mar 29, 2017 at 13:04

4 Answers 4

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White happens to have a couple of nice concrete plans in the particular QGD Exchange variation you mention (1.d4 d5 2.c4 e6 3.Nc3 Nf6 4.cxd5 exd5). One involves e3, f3, Nge2, and a break in the center with e4. The other is a minority attack on Black's a7-b7-c6-d5 pawn structure with b2-b4-b5. You will note that White's stats are much worse in the variation 1.d4 d5 2.c4 e6 3.Nf3 Nf6 4.cxd5 exd5, even though the pawn structures are the same, because he no longer has the f3/e4 plan. So it is not nearly as simple as "the exchange of pawns favors White in the QGD but favors Black in the Slav."

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  • Thanks dfan. Are you of the opinion that the availability of certain good move orders (like f3/e4) are more important in evaluating a position than structural characteristics (for example, like the symmetrical property mentioned in Dag's answer)? Or is the truth somewhere in-between?
    – firtydank
    Oct 24, 2013 at 15:01
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    It all depends. There's no hard and fast rule. Sometimes the short-term characteristics of a position are more important and sometimes the long-term ones are more important. You can make some generalizations but in the end you have to look at each position on a case-by-case basis.
    – dfan
    Oct 24, 2013 at 19:49
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Short answer: In symmetric positions it's difficult to get an advantage if there's nothing concrete. In the Exchange Slav white only has an extra half-move against black's very solid position. Compare with the Exchange French which is even more drawish.

In the Exchange variation of Queen's Gambit Declined on the other hand, there is a structural imbalance that white can try to exploit. The white position is quite flexible, there are many different strategies to choose from that lead to complicated play. White can go for the minority attack (b4-b5), play in the center (f3 followed by e4), and there are other options depending on the concrete line. In most lines white has a small, but real, advantage.

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  • Thanks, Dag, I'm just curious - why would a symmetrical position be advantageous to one particular side? Should black not also benefit from the QGD's assymetry?
    – firtydank
    Oct 24, 2013 at 13:29
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    The QGD is solid, but slightly passive for black. It's not so easy to exploit the asymmetry if you are on the back foot. Also, black's pawn formation isn't as flexible as white's, most black pawn moves weaken the position.
    – Dag Oskar Madsen
    Oct 24, 2013 at 13:43
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    FranS -- it's about the availability of pawn breaks. White's plan with b2-b4-b5xc6 to create a weak pawn on c6 is much easier to accomplish than black's equivalent break f7-f5-f4xe3 to create a weak pawn on e3; for one, it weakens black's king and center. In fact I've never seen that work successfully. It turns out that having pawns in the center matters, and white has two, black one.
    – RemcoGerlich
    Oct 25, 2013 at 7:16
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The Principle of Two Weaknesses is at work here, one weakness is easier to defend than two.

Asymmetry, especially in pawn structure, benefits the player ahead in development, because there is usually available play on more parts of the board. The situation becomes more of a race, and the faster developed player will have an easier way to obtain an advantage.

Symmetry on the other hand, usually leads to play on one same section of the board. In the case of the Exchange Slav, play will most often revolve around Queenside (or otherwise someone has to break the symmetry by playing e4 or ...e5 leading to isolated queen pawn position, at the cost of weakening their own pawn structure).

Simply put, asymmetry often creates potential for two weaknesses, symmetry often creates only one, which is easier to defend against. As white you have the advantage of the first move, so it is wiser to aim for asymmetrical structure if you want any sort of advantage out of the opening.

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  • Thanks for the answer Sunny! I must admit, I don't know if I am entirely sold on the ideas around symmetry that have been proposed by yourself and Dag (but I am not rated high enough to have an opinion that counts, I gladly admit). Like in the Sicilian and French, black tries to break symmetry from the start, while in the QGA, (which seems to be considered better for white), symmetrical positions often arise in the main variations. I know I am probably generalizing a lot here.
    – firtydank
    Oct 29, 2013 at 9:15
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    In the French, white can just as easily go into the French Exchange on 3.exd4, which is essentially another Slav Exchange type position. White doesn't go for this as often because -if he wants to win- it makes black's defensive task easier, as in the Slav Exchange. Great, but what if black doesn't want a draw? Players go asymmetry right off the bat (Gruenfeld, Sicilian, Benoni, etc) and these all lead to fighting games. That's the main point really, practice has shown that symmetrical pawn structures are less "fighting" and easier to defend but of course this is mutual for both sides.
    – Sunny
    Oct 29, 2013 at 10:20
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The exchange variation in the classical QGD can be viewed as theoretically favouring white because after the fourth move in your game, white has both his central pawns while black has only one. However, black now has a semi-open central file which he can use to control the centre through his rooks. Also, he has a queen side pawn majority and he can start pushing his pawns forward on the queen side and try and gain an advantage. So, if black is clever, he can hold his own.

By contrast, the exchange in slav yields a symmetrical position and also allows black to develop his Q Knight to its natural square,so black can be said to have achieved equality, which is definitely a good thing in a queen's pawn game.

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  • Another informative answer to my question - thanks!
    – firtydank
    Oct 30, 2013 at 8:12

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