Classical Variation

French Defense

1.e4 e6 2.d4 d5 3.Nc3 Nf6 4.Bg5 Be7

Black develops naturally with Nf6 and Be7, a flexible and time-tested setup.

Fun fact: At the top level, the most common reply to 4.Bg5 is not 4...Be7 but 4...dxe4, the Burn Variation. Source

The idea

Black develops the knight with 3...Nf6, attacking e4. After 4.Bg5 Be7, Black breaks the pin by putting the bishop in between. The usual continuation is 5.e5 Nfd7, and then 6.Bxe7 Qxe7 or the Alekhine-Chatard Attack, 6.h4.

Plans for White

After 5.e5 Nfd7, the main line is 6.Bxe7 Qxe7 7.f4, supporting e5 and preparing Nf3 and a kingside attack. In the Alekhine-Chatard Attack, 6.h4, White sacrifices a pawn to keep Black's king in the center.

Plans for Black

Black's plan is the same as in most French lines: ...c5 and ...Nc6 against d4, then ...f6 against e5. Castle when it's safe, and use the queen on e7 to support the queenside.

Watch out for

For Black, castling into an attack. With White's pawns on e5 and f4 and the knight driven from f6, Black's king can come under a quick attack on the kingside. Keep a defender near the king, or keep the king in the center for a while.

For White, neglecting d4. Black's ...c5, ...Nc6 and ...Qb6 all aim at d4, and if it falls, White's center collapses.