Chess Opening Theory/1. e4/1...d6/2. d4/2...Nf6/3. Nc3/3...g6/4. f4

=Austrian Attack=

4.f4
This is White's most aggressive variation against the Pirc Defense. White gets in an immediate threat, albeit a not-so-dangerous one, of e5. Black's plan here is usually to develop normally, as there really is no good way of preventing e5. As e5 is not so dangerous anyway, Black usually continues development.

Theory table

 * 1.e4 d6 2.d4 Nf6 3.Nc3 g6 4.f4