Semi Open Games

[King]

In the semi-open games White plays 1.e4 and Black breaks symmetry immediately by replying with a move other than 1...e5. The most popular Black defense to 1.e4 is the Sicilian (1...c5), but the French (1...e6, normally followed by 2.d4 d5) and the Caro-Kann (1...c6, normally followed by 2.d4 d5) are also very popular. The Pirc and the Modern are closely related openings that are also often seen, while the Alekhine and the Scandinavian have made occasional appearances in World Chess Championship games.

[Meister]

Then there's 1...Nc6. A good system with a lot of bite.

[Anonymous]

You didn't mention 1...b6! What a terrible omission!

What does Play 1...b6 recommend for Black after 1.e4 b6 2.d4 Bb7 3.Nc3 e6 4.a3?

[Crossroad]

4...Nf6 followed by c5, cxd4 and d6 going in to a sicilian game.

But besides 3.Nc3 and 4.a3 you can play 3.Ld3 and your Knight would not be pinned with Bb4 in case you don't like that.