Black responds by immediately striking in the center with c5. White's most common reply is 3. e3 defending the d4-pawn and building a solid center. Accepting the offered pawn with 3. dxc5 is possible, but this is much less common as it doubles White's pawns on the c-file and abandons White's plan to construct a closed position for the London. 3. e4 leads to a reversed Albin Countergambit. Where 3. Nf3 is an interesting pawn sacrifice line known as the Shafer Gambit after 3. cxd4 and 4. c3