Cambridge Springs Transpositions...

Just picked up Andrew Martin's Chessbase traininer on the Cambridge Springs and I enjoy it a great deal.

The Chessbase player is another matter.

I have the Andrew Martin Chessbase DVD too. I'd say the stuff on the QGD Exchange is probably very useful.

What didn't you like about Chessbase player? I used the latest version of Chessbase Reader instead of the player provided but that may mostly be still the same thing. Might be a clue that you may not like the Chessbase interface.

I agree with you about the Exchange line variations.  The 11. a5 does help dampen any value in the minority attack.

As for the ChessBase reader I'm just having some trouble with the DVD getting hung up sometimes.  I'd prefer they'd just install the whole shebang on the hard drive.  I guess it must be some paranoia about people copying the material.

Think remember Kasparov explaning 1.d4 d5 2c4 e6 3Nc3 Nf6 4.pxp pxp 5Bg5 Be7 6e3 0.0 7.Bd3 Nb-d7 8Qc2 c6 9Nf3 Re8 10 0.0 Nf8 11Ra-b1 a5 notbeing very careful with earlier move orders. The black squared bishop is important, so after 11a3 Bd6 12 b4 pxp 12pxp ng6 b4 can become a target, or after 12 b5 h6 13BxN QxBetc black gets the two bishops. Think that's part of the reason lines with h3, considered more dangerous for black, white can avoid Bg5 being exchanged? Of course all this subelty works if called Karpov or Kramnik. Good luck with it if a club player.

In carlsbad structure were black's squared bishops have been exchanged, i.e quite common from some bogo indian lines, or ragozin variations, then playing a5 weakens black's queen-side pawn structure.

After 1.d4 d5 2c4 e6 3Nc3 c6 then thr reason 4pxp e6xd5 isn;t impressive for white is that black not commited to nf6 has other possibilites bd6, ne7.

I've seen a5 before but I don't understand it (appreciate if someone would explain it to me).

From what I can see, it slows down white by 1 move... but black spends a move to do it, so it should be no different from an eventual a6 after white plays b4 (a5 will require white to play the prep move a3 while a6 makes white go a4).  The point not being to slow down, but to trade a pair of pawns.

But if white chooses not to push b4, then maybe in some far off improbable endgame my a5 move will just be a weakness.  So I don't understand when and why black will play this.

So my question is, why not wait for b4 first, and only then play a6.  I suppose there must be some value in not committing the pieces on the kingside to a certain setup?  For example either Ng6 or the Ne6-Ng7-Bf5 maneuver.

If you wait for b4 it's too late as after a5 White will push b5!? with a classic minority attack. The immediate a5 means that White can't play b4 without first pushing a3. When White subsequently pushes b4 the queenside might be loose. What Black is really trying to avoid is getting an isolate queen side pawn that then becomes a target.  Or even getting backward or hanging pawns.

There are a number of variations after that so it's rather difficult to make specific comments beyond that. Black will sometimes play Qd6 and if White plays b4 Black needn't take back right away.

Often Black will play g6 these positions blunting the whole Qc2, Bd3 setup and threaten to bring his bad light squared bishop out to Bf5 and trade it off for White's good bishop.

The Nf8 will move at some point but the reason for it sitting on f8 is that it protects the h7 pawn. 

There are a number of better moves for black than Bd6.  Moving the bishop off e7 walks into a pin of N on the Black queen. More mainline moves are g6 or Ne4 or Ng6.

If a club player doesn't want to go into the line I'm not sure I'd be too concerned.

Sorry, maybe I wasn't clear.  ...a5 necessitates a3 while ...a6 necessitates a4.

Black wouldn't respond to b4 with a5.

For example, two ways to reach the same position.

 In the lines I've seen with a6 the pawns on the queen side end up on a6, b7 and c6 whereas a5 seems to avoid that squeeze. 

There are too many variables after that point but a number off different possibilities. Depending on how the play goes the b7 pawn might end up on b5 jamming the queenside.  In some lines Black continues with center play and after something like bxa5 the a3 pawn hangs.

This is more in the spirit of what I want to play. For the time I will probably continue with what I currently play which is a Nimzo and Ragozin.  Even if I played a more mainline QGD I'd probably swing into via the Nimzo as White on Nc3 I go Nimzo and Nf3 I could go mainline QGD (including the Cambridge Springs.) At that point I avoid the Exchange.

IM John Watson's book Mastering the Chess Openings, Volume 2 calls 11...a5 the queenside restraint plan. My understanding is that 11...a5  gets rid of a black queenside weakness a bit earlier and more favourably as compared to black trying to impede white's b5 with ...a6.

I don't think there is a positional reason why 11...a5 is better; it is probably more concrete analysis and calculation that has determined that 11...a5 is better than black playing ...a6 to try to restrain white's b5.

But the line given in post 29 leads to the same position.

It may be one of those moves that's a matter of taste.  I suspect if there's a difference it would take a 2600+ player to appreciate it.  By the way, with the a6-b7-c6 formation I don't feel cramped at all.  But perhaps in the same way I was worried a5 would offer white some chances in some far off improbable endgame, perhaps a6 could do the same.

I even saw a line where black ignores the queenside pawns to gain a tempo on the kingside for piece play.

I played the black side of the exchange in about 10 games at a high level. I'd studied the chapter in Max's books about the middle game on the minority attack, and understood the early nuances from the Petrosian era. In 9 of the games I neutralized white's attempts on the queenside (using Max's ideas) and won on the kingside/centre. In the tenth white played really well and I had to be precise to draw. That guy became junior world champion within 12 months.

So, I really enjoyed playing the black side of the exchange, and am curious to know what has caused it to become popular for white recently, as some suggest.

BTW, I liked flicking in h6, Bh4 as it was a free useful h6 move in the lines played and never played a5.

Just looked John Watson book I have again, there are variations where black is not able to trade off the a6 pawn for a white b5 pawn when it immediately arrives there. e.g.

In this game:

http://www.chessgames.com/perl/chessgame?gid=1068721

20...axb5 21. axb5 Rd6 22. Qa4 Rc8 23. Qa7 Rc7 24. Rc5 is worse for black than what he chose in the game. We can see that that with 11...a5, black's rook is still on the a-file which could be quite useful there in defense. But this I don't think is due to any logical reason other than the variations just work out this way.

I think the Karpov game is a good example of problems with a6. When the smoke clears the a6 pawn is isolated and a perfect example of a minority attack working.

And after a6 followed by b4, a4 Black's position seems cramped to me.

@shell_knight a5 isn't perfect or necessarily better than a6.  But White isn't going to play b4 next move nor a4 the move after.  On a5xb4 Black's pawn chain is still intact.

This is Black at ~2200 rating playing a5. 

In the book "Improve your chess Now", there is an example backward c-pawn v king-side attack, which shows a potential advantage of a6, compared to a5. In that after a4, and b5,black can respond with a5, when gets b4 square for bishop, and a4 is blocked. Mentions that a4 for white was a positional mistake, and white should play na4-c5 blocking a3-f8 diagonal. 

Also discusses Karpov game, and disapproves of the ne4 simplication because leaves black without counter-play. That's the basic idea of playing bd6, is that whilst white is feeding peices to the queen-side to support minorty attack, white's king can be left short of defenders. 

@TwoMove,

Would you mind showing a variation?  I can't quite follow. You should be able to cut & paste from what I posted.

Part of the point of 11..a5 is that White's a4 and b4 are too slow and after 11.a4 h6 then White has to move his bishop move 12. Bh5 or 12.Bh4. Then Black is in fully swing in the center and kingside before White can get any follow up.

Karpove later played h3 I believe stopping Black's light squared bishop from coming out instead of playing for the minority attack after Black's pawn moves ont he queen side.  I don't have any of the analysis in front of me as I'm on the road.

There might be some advantage to a6. I'm not sure the computer analysis nor over the board play bears out Tisdall's 1997 analysis though. It may be that I'm missing your point though as I can't quite follow with the lines. 

The game of Tisdall's example is here http://www.chessgames.com/perl/chessgame?gid=1316533

if the simplying Ne4 is such a good idea, then surely 11BxN preventing it is good, also diverting bishop from b4?! It is suggested 13a4 is a bad positional move, 13Na4-c5 blocking a3-f8 diagonal. Not sure churning variations on Houdini very productive in these positions. Attidute and conceptual ideas maybe more helpful. In Karpov game black is similifying and playing for a draw. Instead it seems black can do better by keeping peices on and looking for kingside counterplay. The asyemmetical pawn structure is not all  a onesided factor in white's factor.

Ah.  That's an entirely different line and Black can deploy his light squared bishop Bg4 with equality.  In the previous variation we were discussing the move was 11. Rab1.

As for Houdini churning away...I don't have Houdini or Fritz 3,987 or others but from what Anand said to Bobby Fischer I suspect that they'd be right in their element here.

Aha! I just picked up Lars Schandorff's book on the Queen's Gambit and found exactly the answer I was looking for with the initial question.  I'd wondered if going in via the Slav/Semi-Slav would be a good way to get to the Cambridge Springs without hazarding the Exchange.  It turns out that it is exactly so.

White can play the Slav Exchange but that's far less likely than the QGD Exchange variation as it yields a symmetrical pawn structure and isn't as dynamic.

In fact, Schandorff covers the Cambridge Springs in the Semi-Slav section and then makes a note that it is really considered part of the QGD but that his recommendation of the QGD Exchange variation means you'd never see it via the normal move variation.  You'd only see it via the Semi-Slav move order.