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Chess Opening Theory/1. d4/1...d5/2. c4/2...dxc4/3. Nf3/3...Nf6/4. e3/4...e6/5. Bxc4/5...c5
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Queen's Gambit Accepted D25-D29
5...c5
Black strikes back at the center, potentially leaving White with an isolated queen's pawn after ...cxd4.
White's main option is /6. O-O/, getting their king out of the center.
An alternative is /6. Qe2/, the Furman variation. This supports the advance of the e-pawn and enables dxc5 without trading the queens.
Theory table
6. O-O a6 Furman variation 6. Qe2 a6 7. dxc5 Bxc5
References
See also
Queen's Gambit Accepted 3...Nf6_4.e3