Chess Opening Theory/1. d4/1...d5/2. c4/2...dxc4/3. Nc3

3. Nc3
Two players have labeled this move misguided, as the knight is vulnerable here to a b7-b5-b4 advance. It also doesn't control d4 or e5, two important squares. The most common and highest-scoring response is for Black to follow up with 3...a6, preparing a future ...b5 thrust which will introduce the idea of attacking the knight with ...b4 and also tries to claim that Black can keep hold of the pawn. This usually leads to a firefight on the queenside. The less common 3...c6 transposes to a position in the Slav defence, with a similar idea in mind.