Queen's Pawn Game: Accelerated London System, Steinitz Countergambit, Morris Countergambit

The Queen's Pawn Game: Accelerated London System, Steinitz Countergambit, Morris Countergambit is a chess opening classified under ECO code D00 in the Closed & Semi-Closed Games family, arising from 1.d4 d5, including the Queen's Gambit, Slav Defense, and related systems. It is reached after 3 moves: 1. d4 d5 2. Bf4 c5 3. e4. The resulting position leaves black to move.