411 REFERENCE · Wikibooks
Chess Opening Theory/1. d4/1...d5/2. c4/2...dxc4/3. Nf3/3...Nf6/4. e3
Reference material by Wikibooks contributors. This retains its source identity and is not 411 news reporting.
Classical variation Classical variation D23-D24
4. e3
This move prepares to develop the kingside and win c4.
Theory Table
4...e6 Bxc4
See also
Queen's Gambit Accepted