What whites gains is:
The open c-file.
2 center pawns vs. 1
Pressure against c7.
After Qb3 pressure against the bishop, d5, and b7.
Why 5. cd5:? [Queens Pawn D02 with 2. Bf4]
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Aug 7, 2019
0
#3
IMBacon wrote:
What whites gains is:
The open c-file.
2 center pawns vs. 1
Pressure against c7.
After Qb3 pressure against the bishop, d5, and b7.
But now this image.
This is in the Fritz (14) book. Also whithout the book Stockfish favors Rc1.
Why isn't cd: not right in this occasion, as it it would meet all of your mentioned advantages.
What is the essential difference?
Aug 7, 2019
0
#4
First of all. I need to know what you mean by "favors" If you are asking why an engine prefers one move over another by something ridiculous like .10???? There is essentially no difference.
Besides all that. You're asking about 2 different positions.
But in the second position. 1.cd5 doesn't work due to the following 1...Nd5 2.Nd5 Qd5 and black has a HUGE lead in development. And if 1.cd5 Nd5 2.Bg3 h5 black has pretty much everything pointing at the kingside.
Aug 8, 2019
0
#5
In the second position, both Rc1 and cxd5 will eventually be played. It’s just a move order thing. You can play either on the 8th move.
In the first position, one of the reasons (yes there’s more than one) to play 5.cxd5 is that after 5...exd5 6. Qb3 black will be forced to play 6...Nc6, which prevents ...c7-c6 and makes b7 difficult to defend. Normally black wants his knight on d7 rather than c6.
cxd5 can be seen in main line QGD as well, where black puts his DSB on d6/e7 and plays c6, Nbd7. The idea is b2-b4-b5xc6 and (after black retakes with pawn) attack the backward c6-pawn.
In the first position, one of the reasons (yes there’s more than one) to play 5.cxd5 is that after 5...exd5 6. Qb3 black will be forced to play 6...Nc6, which prevents ...c7-c6 and makes b7 difficult to defend. Normally black wants his knight on d7 rather than c6.
cxd5 can be seen in main line QGD as well, where black puts his DSB on d6/e7 and plays c6, Nbd7. The idea is b2-b4-b5xc6 and (after black retakes with pawn) attack the backward c6-pawn.
Aug 8, 2019
0
#6
Thank you IMBacon & inkspirit!
The context is that I've engaged in a little project to discover the motivations for c4xd5: in the Queens-Pawn (and later QGD) openings beyond the trivial tactical motifs. By extension, I'll also check out d5xc4: from blacks perspective, again beyond the usual tactical motifs.
White played 5. cd5:
See screenshot.
What does white gain from this move? In many cases white doesn't break up the center with cd5: for quite a while. So, in this case, what does white achieve (or prevent) with this move? How is it better than, say, 5. e3 or 5. Nf6? (says a recent Stockfish engine).