In the Marshall Gambit, part of the Semi-Slav Defense, Black plays 1.d4 d5 2.c4 c6 3.Nc3 e6 4.e4, sacrificing a pawn to open the e-file and activate pieces. Played after 1.d4 Nf6 2.c4 e6 3.Nf3 c5 4.d5 b5, the Blumenfeld Countergambit offers a pawn to open lines on the queenside and challenge White’s center. In […]