Caro-Kann, Smyslov variation : Can Black punish early 5.c4 in this position? Recently I have posted a question about declining the Marshall Gambit in the QGD, and asked if Black can transpose into another solid opening, as one way of defense.

After analyzing the first position in the below diagram, I have realized that it can crop in a up specific Caro-Kann move order. What raises my hopes even higher is that White does not play 5.c4 but 5.Bc4 there, which means that 5.c4 is weak and has its drawbacks. 

Compare the following diagram:

[Title "QGD, Marshall gambit"]
[fen "r1bqkbnr/pp1n1ppp/2p1p3/8/2PPN3/8/PP3PPP/R1BQKBNR w KQkq - 0 6"]


and this one:

[Title "Smyslov variation ( B17 ) after 5.c4"]
[StartFlipped "0"]
[fen "r1bqkbnr/pp1npppp/2p5/8/2PPN3/8/PP3PPP/R1BQKBNR b KQkq - 0 5"]


Although in the second diagram Black has better moves than 5...c6, I believe that favorable transposition can still be achieved.

To determine if this is true, I need to know how Black refutes 5.c4.

Under refutation I consider Black achieving at least a fully equal position.

Hence these questions:


Can Black equalize or achieve advantage in the position from the second diagram?
If answer to the first question is positive, can you demonstrate it with concrete lines?


Thank you.

Best regards.
5.c4 is bad in the Smyslov variation because black can equalize instantly with 5...e5! 6. dxe5 Qa5+ and 7...Qxe5.  Black is not better though, it merely gives black an easy game with the queens off.

For the complete line:

[Fen ""]
[Title "Smyslov Variation"]

1. e4 c6 2. d4 d5 3. Nc3 dxe4 4. Nxe4 Nd7 5. c4 e5 6. dxe5 Qa5+ 7. Bd2 Qxe5 8.
Qe2 Nc5 9. Nxc5 Qxe2+ 10. Nxe2 Bxc5 *


In the line you give with 5...e6, white retains a comfortable advantage.  White can play the standard plan of Nf3 and Bd3 and either try to keep the knights on the board with Nc3 after black plays Ngf6 or swap a pair of knights with a good position based on black's bad light square bishop.

Some example lines that give white an edge:

[Fen ""]
[Title "Marshall Gambit"]

1. e4 c6 2. d4 d5 3. Nc3 dxe4 4. Nxe4 Nd7 5. c4 e6 6. Nf3 Ngf6 7. Bd3 (7. Nxf6+
Nxf6 8. Bd3) (7. Nc3 c5 8. Be2 cxd4 9. Nxd4 Bb4) 7... Nxe4 8. Bxe4 Nf6 9. Bd3
Bb4+ 10. Bd2 *