Queen's Gambit Declined: Semi-Tarrasch Defense, Symmetrical Variation

The Queen's Gambit Declined: Semi-Tarrasch Defense, Symmetrical Variation is a chess opening classified under ECO code D40 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 e6 3. Nc3 Nf6 4. Nf3 c5 5. e3 Nc6 6. Bd3 Bd6 7. O-O O-O. The resulting position leaves white to move.