Ruy Exchange--Why not 4...bxc6?

In his KID book, he says 99.999% lines are winning for White in the FPA.

I thought Qd6 was a move.

(after dxc6 0-0)

I don’t understand why you would give up your D pawn

Is that what "I've never understood" means? And, by the way, has abiogenesis23 been here since 2013?

Was it necessary to ask whether or not abiogenesis23 had ever understood something? Wasn't that something that abiogenesis23 was in a position to know?

I still do not see anything about everyone else being wrong. I suppose it could be argued that abiogenesis23 was presupposing "basically nothing" as compensation for giving up the bishop for a knight, but the I've-never-understood part of the sentence seems to me to indicate a recognition of possibly incomplete understanding. Anyway, you are reacting to a 2013 post.

nothing wrong with this move

"... leaves White with the initiative." - Shaun Taulbut (1996)

"No one plays 4...bxc6?, since after 5 0-0 d6 6 d4 White is a whole tempo up on the Steinitz Deferred [(1 e4 e5 2 Nf3 Nc6 3 Bb5 a6 4 Ba4 d6 5 Bxc6+ bxc6 6 d4)]." - IM Sam Collins (2005)

Fischer in game against Gligoric in "60 Memorable games" comments on 4...bxc6, but can't remember what recommends.

You have the white pieces which means you are the one pushing for a win. Trading pieces and giving up the bishop pair doesn't exactly help with that. Trading simplifies the game closer to a draw.

"Black has two bishops, while White has a better pawn-structure. After d4, exchanging the black e-pawn, the white kingside majority is healthy (meaning it can create a passed pawn) while the black queenside majority isn't." - IM Sam Collins (2005)

http://www.chessgames.com/perl/chessgame?gid=1258181

I used to use this line.

It's not great:

It's not great, most of my games looked something like the line above.

White has a great position. He's more developed, and has more space in the center.