Advance Variation
French Defense
1.e4 e6 2.d4 d5 3.e5 c5 4.c3 Nc6
White immediately gains space with e5, locking the center and fighting for the d4/c5 squares.
Fun fact: Aron Nimzowitsch believed 3.e5 was White's best move against the French, and Alexander Grischuk has championed it at the highest level. Source
Practice this lineThe idea
White pushes 3.e5 at once, gaining space and locking the center. Black hits the base of White's chain straight away with 3...c5, and after 4.c3 Nc6 the fight is all about the d4 pawn.
Plans for White
Support d4 with c3 and Nf3, then develop with Bd3 or Be2 and castle. If Black's pressure on d4 becomes too strong, White can consider giving it up with dxc5 to grab the c5 square.
The pawn on e5 cramps Black's kingside: the knight can't use f6, so White often has attacking chances there once Black castles.
Plans for Black
Pile up on d4: ...Qb6, ...Nc6, ...Bd7 and ...Nge7-f5. Once White's pieces are tied to defending it, ...f6 opens the position.
The queen on b6 also eyes b2, so White can't always develop the queen's bishop freely.
Watch out for
For Black, grabbing d4 at the wrong moment. After 5.Nf3 Qb6 6.Bd3 cxd4 7.cxd4, the tempting 7...Nxd4?? loses the queen: 8.Nxd4 Qxd4 9.Bb5+ uncovers White's queen against Black's. The safe move is 7...Bd7, stopping the check first.
For White, losing d4. Count the attackers and defenders on d4 before every move, because if it falls, White's space advantage is gone.
The discovered attack on d4
5.Nf3 Qb6 6.Bd3 cxd4 7.cxd4 Nxd4 8.Nxd4 Qxd4 9.Bb5+ Bd7 10.Qxd4