411 REFERENCE · Wikibooks
Chess Opening Theory/1. d4/1...d5/2. c4/2...e6/3. Nc3/3...Nf6/4. Nf3/4...Be7/5. Bf4/5...O-O/6. e3/6...c5/7. dxc5
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Queen’s Gambit Declined, Blackburne Variation, Main Line
7. dxc5
White captures the c-pawn with 7. dxc5, forcing the black bishop on e7 to waste a tempo with 7...Bxc5. Note that 7...dxc4 leads to a favorable endgame for white after 8. Bxc4 Qxd1+ 9. Rxd1, where white enjoys more active pieces.