Why are side pawns better than center pawns in this position?

Question

So center pawns are usually regarded as more powerful than side pawns, which is why I have a question about this position.

After 1. d4 d5 2. Bf4 c5 the engine and theory recommend playing 3. e3 to defend the pawn on d4, but if black exchanges for the pawn on d4, doesn't black end up with two center pawns and white end up with one because they exchanged the side c-pawn for the center d-pawn?

 [FEN " "]
 [StartPly "5"]
 1. d4 d5 2. Bf4 c5 3. e3

Wouldn't it be better to play 3. c3 so you can keep the center pawns?

 [FEN " "]
 [StartPly "5"]
 1. d4 d5 2. Bf4 c5 3. c3

Answer 1

Chess strategy is complex and has several ingredients mingling at the same time. It is true that 3 c3 helps white mantaining two center pawns if black decides for a c:d4 pawn exchange. But black isn't forced to that and the move c3 has some incovenients. To list just two:

• blocks the c3 square which is the natural place for developing the Q-side knight;

• gives up the idea of attacking black's center with the move c4.

The move 3 e3 on the other hand helps white development since it opens the way out for the K-side bishop.

Moreover, the loss of one centre pawn is balanced by the fact that after white will castle K-side the absence of the e pawn will make the e-file a natural place for a white rook which will play an important role in the fight over the e5 square.

Answer 2

I am really not an expert of this opening, but maybe 3.c3 is better in a sense.

After 1.d4 d5 2.Bf4 c5 3.e3, according to you, black should "refute" this inaccuracy by taking immediately on d4 3..cxd4 4.exd4 and now we have the Caro-Kann Exchange Variaton, with white having played the suboptimal Bf4 (1. e4 c6 2.d4 d5 3.exd5 cxd5 4.Bf4). After 4...Nc6 5.c3 Bf5(!) black has solved the problem of how to develop its white squared bishop and should have no further problems. Of course it is nothing for black in the winning sense.

 [FEN " "]
 [StartPly "5"]

 1.e4 c6 2.d4 d5 3.exd5 cxd5 4.Bf4 Nc6 5.c3 Bf5

In the line 1.d4 d5 2.Bf4 c5 3.c3 black can also take on d4: 3...cxd4 4.cxd4, but then we have reached the Slav Exchange Variation (1.d4 d5 2.c4 c6 3.cxd5 cxd5 4.Bf4) and here 4.Bf4 is found among the top moves. Furthermore the Slav Exchange Variation poses black more problems to consider, than the Caro-Kann Exchange Variaton.

 [FEN " "]
 [StartPly "4"]
 1.d4 d5 2.c4 c6 3.cxd5 cxd5 4.Bf4    

Considering values of pawns alone has led us to a good idea in this case. Of course it should go without saying that in general there are more factors to consider in a chess postion, Space, Material and Activity among the top candidates. Only a good engine and a lot of experience can help us out here.

One example to illustrate the idea: 1.e4 c5 2.Nf3 e6 3.d4! cxd4 White voluntarily allows black to exchange his c-pawn against a valuable center pawn. This is a positional problem, but feasable because white gets something in return, more space and more active pieces. White can simply take back (4.Nxd4) or play the sly 4.c3, the Morra Gambit. Now it is white posing the positional threat of promoting his c-pawn to a center pawn with 5.cxd4. Black can accept the challenge, after 4..dxc3 5.Nxc3 white has traded material for space and time, it is playable AFAIK. Black can also defend with 4..d3.

 [FEN " "]
 [StartPly "5"]
1.e4 c5 2.Nf3 e6 3.d4! cxd4 4.Nxd4 ( 4.c3 4...dxc3 ( 4...d3 ) 5.Nxc3)

Answer 3

Move 3 is a bit early for such positional evaluations, but some food for thoughts:

• after 3...cd 4.ed, e7-e6 will be played, rather sooner than later but then the pawn structure in the center is fixed, which makes it hard for Black to "exploit" his extra central pawn. Any expansion with ...f6 and ...e5 is out of question for at least the next 20 moves because of White control over e5 (Pd4, Nf3, Bf4, Re1...); even if it somehow becomes possible, it is not sure to be desirable at all.

• For the sake of controlling the center, White's c-pawn is not much worse than Black's e-pawn. Indeed, while Black cannot hope for ...e5, White may change the pawn structure with c2-c4 at some point, heading for an isolani.

• Beside pawns, the center is also useful for pieces. White chances of occupying the e5-vanguard position with a knight are much better than Black's chances of occupying e4 because of the semi-open e-file.

• Since she has a tiny advance is development, White often tries to select non-symmetrical pawn structures, so the exchange Caro-Kann structure with 3.e3 cd 4.ed might be more attractive for most players than the exchange Slav structure with 3.c3 cd 4.cd.

All that being said, 3.c3 is a decent move that some players would prefer over 3.e3. And in both cases, Black is not at all forced to release the tension by 3...cd.

And by the way, 3.e4 is a whole different story.

Answer 4

The number of central pawns is one of the factor that matter in the evaluation of a position, but it's definitely not the only one.

While I think both 3.e3 and 3.c3 are playable, 3.e3 helps your development, while 3.c3 does not. If Black takes on d4, White gets an amazing outpost on the e5 square. In fact, Black would wish he could put his e6 pawn on the "c" file instead so that it could fight for the control of e5 and get a similar outpost on e4.

Answer 5

Just a small addendum: As a Bf4 player who never plays London but his own obscure systems (which are extremely dangerous for both sides - in the days before computer preparation, I clobbered a few GMs with them I only play e3. My own experience is that the most doubly-edged Black plan is pestering b2 with his queen. e3 (developing, also keeping the option Nc3, eat b2 and die!) is asking for it. After c3, you can wuss out by answering Qb6 with Qb3, but that is extremely drawish. Oh, and immediate cxd4 gives White a nice outpost on e5.