The Sicilian Defense is a popular chess opening that begins with the moves 1.e4 c5. It is favored by many players because it allows Black to counterattack and create an unbalanced position, which can lead to dynamic play. The opening aims to control the center while also preparing for active piece development. This defense is named after the Italian chess player Francesco Siciliano, who contributed to its early analysis. The Sicilian Defense has many variations, including the Najdorf and Dragon variations, each offering different strategies and tactical opportunities for both players.