The Blackmar-Diemer (BDG) is a classic gambit opening, sacrificing a pawn early in development in order to open up lines and race ahead with strong developing moves. Unlike the other well-known gambits, such as the Scotch Gambit, King's Gambit, Smith-Morra Gambit and the Danish Gambit, the BDG is a Queen's Pawn opening. Many theorists have questioned the soundness of the BDG, but Ken Smith and John Hall have thoroughly analyzed this exciting opening and make a strong case for why you should add it to your opening repertoire!