From my experience, Black players has been always debating which variation to play after 1.d4 d5 . 2c4 c6 3.Nf3 Nf6 4.Nc3 dxc4 5.a4. My suggestion is reliable 5...e6. I offer a very detailed coverage from the starting position after 5...e6. Depending on White choice the play might be very sharp (White can sacrifice a pawn in several variations), or more positional after 6.e3. If you study my file you are going to feel very comfortable for many years ahead! Published for Advanced level only.