Queen's Gambit Accepted: Central Variation, Rubinstein Defense, Yefimov Gambit

The Queen's Gambit Accepted: Central Variation, Rubinstein Defense, Yefimov Gambit is a chess opening classified under ECO code D20 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 4 moves: 1. d4 d5 2. c4 dxc4 3. e4 c5 4. d5 b5. The resulting position leaves white to move.