Symmetrical Variation, Four Knights Variation

The Four Knights Variation of the Symmetrical English arises after 1. c4 c5 2. Nf3 Nf6 3. Nc3 Nc6, with all four knights developed and the pawn structure still perfectly mirrored. It is filed under ECO A35 and is also reached through move orders such as 1. c4 c5 2. Nc3 Nc6 3. Nf3 Nf6. Because Black has answered both knight moves in kind, White must decide how to break the symmetry, and the choice on move four sets the character of the game. The engine judges the position roughly balanced, and White scores slightly better in practice.

4. g3 is the most popular reply and the most successful one for White. It prepares Bg2 to bear down on d5 and the long diagonal. Black's main answer, 4...e6, is the Keres-Parma System, which declines the mirrored fianchetto and aims for ...d5 to contest the center directly. 4. d4 opens the position at once and leads to open, Sicilian-like play. 4. e3 is a quieter plan that prepares d4 so White can recapture with a pawn and keep a central presence.