Chess Opening Theory/1. e4/1...d5/2. exd5/2...Nf6/3. c4

As Black didn't recapture the d-pawn straight away, White defends it, hoping to stay up the material.

Black has two main options: to chip away at the pawn chain with 3...c6 or 3...e6.

After 3...c6, White could trade 4. dxc6?! Nxc6=. However, although White is up a pawn, this helps Black to develop and Black is thought to have full compensation.

Better is 4. d4 (or 4. Nc3 which will transpose), and after 4...cxd5 the position has transposed into the Panov-Botvinnik attack in the Caro-Kann. Because this line used to be considered better for White, 3. c4 used to be the overwhelming choice of strong players. It has fallen out of fashion for three reasons. Firstly, because the Panov-Botvinnik is now only considered even. Secondly, 3. d4 became more popular as a serious try at an advantage for White. Thirdly, the rise of the response 3...e6.

3...e6 is the Icelandic-Palme gambit. After 4. dxe6 Bxe6, Black looks for attacking chances, hoping their development lead and an open position will prove an advantage.

1. e4 d5 2. exd6 Nf6 3. c4