I've just been looking again at the Slav/Semi-Slav as a way to defend 1.d4 -- much against my better judgment, as I prefer to avoid fashionable openings, but presumably they're fashionable for a good reason. If you'd like a bird's eye view of the complex with some example games, read on here.
"The most important feature of the chess position is the activity of the pieces. This is absolutely fundamental in all phases of the game (opening, middlegame and especially endgame). The primary constraint on a piece's activity is the Pawn structure."
|Michael STEAN, in Simple Chess.|