Classical Variation, Zurich Variation

The Zurich Variation, also called the Milner-Barry Variation, meets 4. Qc2 with 4...Nc6, blocking the c-pawn to build a ...d6 and ...e5 center that frees the light-squared bishop. White mostly replies 5. Nf3, and 5. Nf3 d6 is a topical line. After ...e5 White usually closes the center with d5 and plays on the queenside, while Black regroups the knight and aims for ...f5 on the kingside. The line is out of fashion but often arises from the Black Knights Tango.