Chess Opening Theory/1. e4/1...c6/2. d4/2...d5

This is the main line of the Caro-Kann defence, a semi-open game that tends to contain lines with minor piece play.

Black's threatens to capture ...dxe4. White has four main plans to deal with the central tension: close the centre, capture first, or prepare to recapture with knight or pawn.

3. e5 is the advance variation. White closes the centre and takes more space. This is the modern-day main line at all levels. The main line continues 3...Bf5 4. Nf3 e6 5. Be2, and Black either plays for an early ...c5 pawn break or contents themselves with developing in a cramped position. White has a choice of several sharp sidelines, including 3. Nc3 & 4. g4, sometimes called the Shirov attack.

3. exd5 is the exchange variation. Black retakes 3...cxd5 and frees the c6 for their knight again. Then White's main options are the Rubinstein variation, 4. Bd3 Nc6 5. c3 Nf6 6. Bf4, which leads to a Carlsbad pawn structure, or the sharp Panov attack, 4. c4, where White is willing to accept an isolated queen's pawn position for rapid development and attacking chances.

3. Nc3, the classical, and 3. Nd2, the modern variation, prepare to recapture with the knight. Usually, both moves reach the same position after 3...dxe4 4. Nxe4. The two move orders differ in how they may answer the sideline 3...g3.

3. f3, preparing to recapture with the pawn, is the Maróczy or fantasy variation. Black doesn't usually want to allow White to retake in the centre with a pawn (though 3...dxe4 4. fxe4 e5 is playable) and the main continuation is 3...e6 and a closed, manoeuvring game.

Defending the pawn with 3. Bd3!? is irregular as 3...dxe4 4. Bxe4 Nf6 gives Black the initiative.

3. c4?! transposes into the Diemer gambit of the Slav defence, otherwise seen after 1. d4 d5 2. c4 c6 3. e4.

3. Be3?! is the Mieses gambit. The usual idea is 3...dxe4 4. f3 exf3 5. Nf3, a pawn sacrifice for a development lead similar to the Blackmar Diemer gambit, 1. d4 d5 2. e4.

1.e4 c6 2.d4 d5

Wikipedia has related information at Caro–Kann.

• Schandorff, Lars (2010). The Caro-Kann. Quality Chess. ISBN 1906552568.