Queen's Gambit Accepted: Classical Defense, Russian Gambit

The Queen's Gambit Accepted: Classical Defense, Russian Gambit is a chess opening classified under ECO code D27 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 7 moves: 1. d4 d5 2. c4 dxc4 3. e3 Nf6 4. Bxc4 e6 5. Nf3 c5 6. O-O a6 7. e4. The resulting position leaves black to move.