411 REFERENCE · Wikibooks
Chess Opening Theory/1. d4/1...d5/2. c4/2...e6/3. Nc3/3...Nf6/4. Nf3/4...Bb4
Reference material by Wikibooks contributors. This retains its source identity and is not 411 news reporting.
Ragozin Defence D38 Queens Gambit declined
4...Bb4 · Ragozin Defence
The mainlines continues either
/5. Bg5/ h6 (Moscow variation)
/5. Bg5/ dxc4 (Vienna variation)
Theory table
Moscow variation 5. Bg5 h6 Vienna variation 5. Bg5 dxc4 Alekhine variation 5. Qa4+ Nc6