O'Kelly Variation, Normal System

The Normal System is White's direct reply 3. d4 to the O'Kelly Variation, opening the center in Open Sicilian fashion. It is the response that Black's 2...a6 was designed to meet, because the pawn on a6 keeps a white knight off b5 once Black plays ...e5. Black nearly always takes with 3...cxd4. The alternative 3...e6, the Drazic Variation, is a distant second, and 3...Nc6 is rare and scores poorly for Black.

After 3...cxd4 White has four named options. The natural 4. Nxd4 allows the immediate 4...e5, known as the Taimanov Line, or the main sequence 4...Nf6 5. Nc3 e5. In that sequence, 6. Nde2 is the most careful way to keep e4 defended against ...Bb4, and 5. Bd3 is an earlier way of doing the same. The Smith-Morra Line 4. c3 offers a pawn for development. The Zagorovsky Line 4. Qxd4 centralizes the queen at once. The Cortlever Gambit 4. Bc4 develops the bishop and leaves the d4-pawn in Black's hands for the moment. The engine rates the position as roughly balanced, and in online games Black scores slightly better than White.