c5?! in the QGD

It is common for those who know their chess stuff to insist that "x.)c5?!" is a dangerous move in the QGD game, because it releases the important central tension for a cheap space-gaining move that later can be challenged by black's ...b6, or what have you. However, what about the viability of white's c5 in a situation like the one shown below?

So look at the final position here. Has white sacrificed his central tension for something less powerful?

I say 7. c5 Qc7 8. e3 Nbd7 9. Bd3 O-O 10. O-O e5 is about equal.

By the way you sliped into the Semi-Slav; 5...dxc4 looks like the critical line.

Alright thanks. So keeping the pawn on c4 is probably the best idea. Sorry, I always paint openings that look like this "QG" -- from pure (sometimes wilful) ignorance :)

Yes the bishop is bad, but white will eventually try for the b5 break and play on the queenside.

It's similar to the panov caro where white plays c5 but missing are black's c and white's e pawn.  One danger for white is his weak d pawn but here you have e3 so it seems like an ok try.

One thing to be sure of in these kinds of positions is that your queenside is developed or close to it.  For example b6 b4 a5 a3 and your a pawn isn't pinned to your rook because your queen protects it.

It is a much slower plan for white though, slowly working up to the b5 break and putting pieces on the queenside.  Black will of course be looking at b6 and e5 breaks.

So it certainly seems like an option, but much more tame / easier for black to deal with than keeping the tension in the center.  The plus being he can't gang up on your pawn chain.  No dark bishop and often in the caro line the king's knight goes to f5 to pressure d4.

I think black will be able to play e5 in such positions and that seems to be ok, but you can try it.

Hum... Okay. Mediocre position. Maybe nice to try every now and then, is how I see it.

White is no worse.

The problem is 5. Bf4  Bd6. I don't think either of those moves is very good. I know you want to talk about the c5 idea, but you posted in the opening forum, so you are going to get an earful. 

First off, move order issues. 1. d4 d5 2. c4 e6 3. Nc3 Nf6 4. Nf3 c6 is the starting position of the Semi-Slav. If you are playing White, you opened a complicated can of worms. 4. Bf4 stays in the QGD. For example, 4...c6 5. e3 Bd6 6. Bxd6 Qxd6 7. Nf3 Nbd7 8. c5 Qc7 is similar to the line you had. It is not the same, White no longer has Ne5 and f4 ideas, but Black also lacks the ability to play b6 and Ba6 without a5. 

Second, did you realize 5. Bf4 was a gambit? The most common moves are 5. e3 directly protecting the c4 pawn and 5. Bg5 so that dxc4 e4 comes with the threat of e5. After 5. Bf4 dxc4 White has a few moves at his disposal. (a) 6. a4 Bb4 7. Qc2 b5 is the statistical mainline, at least according to chess 365. Black has an extra pawn and use of the b4 square. (b) 6. e4 is the most aggressive line. 6...b5 (6...Bb4 7. Qc2 b5 is an option) This is probably considered a sideline of the Geller Gambit usually reached via 1. d4 d5 2. c4 c6 3. Nf3 Nf6 4. Nc3 dxc4 5. e4 b5 6. Bf4 e6. Black still has the extra pawn and White is the one with something to prove. Getting the pawn back with (c) 5. e3 b5 6. a4 Bb4 7. axb5 cxb5 8. Bxb8 Rxb8 9. Rxa7 does not inspire confidence. Black has the bishop pair and a potential passed pawn on the queenside. White's light squared bishop does not have a very bright future.

Lets be clear. If black doesn't play ...c5 at some point in the qgd, slav or semi-slav he will be squashed off the board. If white plays c5 at some point in the qgd, slav or semi-slav its a horrific mistake that releases the tension in the centre of the board.

in the game above why not just play e3, let the bishop out and get on with the game.

Arutha: aggressivesociopath, rating 1700+ standard, says "white is no worse," and I tend to agree with him.

The point is not whether you CAN just play e3; rather, the question is on other options, as a matter of learning more about chess (and in particular, QGD and Slav variations.)

To clarify, I gave "White is no worse" as an assessment of the position after 7. c5. I did not compare the move to 7. e3, I merely think the position is equal. I spent less time on this position then after 5...dxc4.

By the way if you don't think White can play c5 in the Queen's Gambit Decline you are not paying attention. The position after 1. d4 Nf6 2. c4 e6 3. Nf3 d5 4. Nc3 Be7 5. Bf4 O-O 6. e3 Nbd7 7. c5 c6 8. h3 b6 has been reached in high level games. I gave the move order from Svidler-Topalov Makedonia Palace GP 2013. Girshuk-Aronian Canidates 2011 also comes to mind.

It makes less sense to squeeze Black on the dark squares with the dark squared bishops off the board. White also has less control over e5, so Black can break in the center unless White plays Ne5 and f4 at some point. Hence the position is about equal.

Just becase the 2700-club do it doesn't mean its totally playable. They play it for very concrete reasons. I stick by what I said in a general sense. Need I remind everyone that white plays c4 to divert the d pawn away from its control of e4 so white can play for it himself. To take away the tension without getting somethingconcrete for it is a mistake. In the first game above, black has traded off his dark squared bishop for whites. c5 in this case does nothing to pressure blacks dark squares. Its not a weakness for black. How can it be? The only pieces capable of using them are the Queens. If white had traded blacks dark-squared bishop for one of his knights then MAYBE.

c5 is a very poor move. It makes black's e5 break very easy, and promises black an easy game ripe with opportunities to launch vicious kingside attacks.

White should not play Bf4, however, because that is certainly not best. Black is threatening to play dxc4, and protect it with b5, winning a pawn, and your response is the cray cray Bf4?!, (is that a gambit?). Instead Bg5 is obvious and best (if black plays dxc4, then you play e4, and you will get back your material. Also good is e3, both of those lines are quite interesting and fun!

Yeah, Bf4 is a gambit. I believe that has already been brought up. I find those kind of pawn gambits are fine in blitz games - basically, the faster the time control is, the safer it is to give away a pawn in return for, in this case, centre control. Pawns aren't everything bro, tho it's true that Bg5 is probably better. THAT is irrelevant, since the final position is what I'm concerned about.

Prove c5 is a very poor move. Just because black has an easy e5 break doesn't make it a poor move. There are other considerations to take in mind. 

I bet if you plugged the top position into a quality computer, white would still have a slight edge. It's playable, and it's not a terrible mistake at my (and your) level of play.

Blitz is blitz, but I don't trust the pawn gambit a single bit even though White can actually get the pawn back. Either with the line I gave as line c above or with the slow as molasses 6. Bxb8 Rxb8 7. Ne5, which involves trading off a devolped piece for an undevolped one and moving the knight twice in the opening.

Its well known that computers love c5 in QGD positions. Its also well known grandmasters don't.

It depends on the position.

It's hard to say what opening this will end up until either Black decides to do dxc4 (Slav/Semi-Slav) first or White plays cxd5 first (Slav Exchange/QGD Exchange).

White needs to prevent black from playing...e5 in the final position instead of e3, b4, a3 or black will have a relatively easy game.