The Sicilian Defence: 1.e4 c5. Black breaks the symmetry and eyes the d4 square from the side. It is the most popular and most combative reply to 1.e4.
In the Open Sicilian, White opens the centre with d4. Play d4.
The Najdorf Variation: 5...a6. Because of the unbalanced pawn structure, both sides usually attack on opposite wings. The Sicilian is the weapon of Black players who want to win.