Chess Opening Theory/1. e4/1...e6/2. d4/2...d5/3. e5/3...c5

=French Defence: Advance Variation= Black's plan is straightforward: They want to eliminate White's pawns on d4/e5 - and after doing so, Black will find it easier to develop the pieces of their kingside to good squares.

White's most common continuation is 4. c3, in order to support their d4-Pawn. If Black follows with 4...cxd4, White can simply replace their d-Pawn with 5. cxd4, and Black's position will be just as cramped as it was before.

There are some rarely played alternative variations for White: Both 4. Nf3 and 4. Qg4 have the idea of (temporarily) sacrificing the d4-pawn in order to get some initiative on the kingside as a compensation. White can also play 4. dxc5, though this helps Black's intention of eliminating White's pawn center.

Theory table
1.e4 e6 2.d4 d5 3.e5 c5