Chess Opening Theory/1. e4/1...e6/2. d4/2...d5/3. e5/3...c5/4. c3/4...Nc6/5. Nf3/5...Qb6/6. Bd3/6...cxd4

=French Defence: Advance Variation=

Black trades the pawn on c5 for white's d4 pawn. Black appears to be able to win the pawn but 7.cxd4 Nxd4? 8.Nxd4 Qxd4?? 9.Bb5+ would win the Black queen, so 7...Bd7! is the main move after 7.cxd4. 7.O-O is a modern gambit, sacrificing a pawn for quick development and an attack.

Theory table
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1.e4 e6 2.d4 d5 3.e5 c5 4.c3 Nc6 5.Nf3 Qb6 6.Bd3 cxd4