Queen's Gambit Declined: Orthodox Defense, Fianchetto Variation

The Queen's Gambit Declined: Orthodox Defense, Fianchetto Variation is a chess opening classified under ECO code D66 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 9 moves: 1. d4 d5 2. c4 e6 3. Nc3 Nf6 4. Bg5 c6 5. Nf3 Be7 6. e3 Nbd7 7. Rc1 O-O 8. Bd3 dxc4 9. Bxc4 b5. The resulting position leaves white to move.