411 REFERENCE · Wikibooks
Chess Opening Theory/1. d4/1...d5/2. c4/2...dxc4/3. Nf3/3...Nf6
Reference material by Wikibooks contributors. This retains its source identity and is not 411 news reporting.
Queen's Gambit accepted D23-D29 Queen's Gambit accepted
3...Nf6
Black develops and prevents White from establishing a pawn center with e4.
Theory table
4. e3 e6 + Showalter variation 4. Nc3 Mannheim variation 4. Qa4+ Nc6
References