A common idea in the Sicilian, Black tries to develop first the queenside as comfortably as he can and only then proceeds with the completion of the kingside development. Still, keeping the king in the center for long is a risky strategy.
1. e2e4  1... c7c5  2. g1f3  2... d7d6  3. f1b5 The Moscow line is very popular nowadays. 3... b8d7 This move leads to a complex battle. 4. e1g1  4... a7a6  5. b5d3 The main variation. 5... g8f6  6. f1e1  6... e7e6  7. d3f1 This move scores better than 7.c3 at the moment. White intends to open the center as soon as possible.