Home › Openings › Queen's Gambit Declined › Queen's Gambit Declined: Harrwitz Attack › Queen's Gambit Declined: Harrwitz Attack, Two Knights Defense Queen's Gambit Declined: Harrwitz Attack, Two Knights Defense, Blockade Line ECO D37 · 1. d4 Nf6 2. c4 e6 3. Nc3 d5 4. Nf3 Be7 5. Bf4 O-O 6. e3 Nbd7 7. c5 Practice this opening · Play against the computer