Najdorf Variation, Opocensky Variation, Modern Line

The Modern Line differs from the Traditional Line, 8...O-O, in that Black develops the light-squared bishop to e6 before castling. This adds a defender to d5, the square White's pieces aim at in this structure. White most often answers with 9. f4, preparing f4-f5 against the bishop. The main alternatives are 9. Be3 and 9. Kh1. The engine rates the position roughly balanced, and decisive results are split fairly evenly between the two sides.