Rossolimo Variation

After 1. d4 d6 2. Nf3, the move 2...g6 prepares ...Bg7 and postpones ...Nf6. That keeps several setups open for Black: a Modern or Pirc structure if White plays e4, a King's Indian-type game after c4, and a choice between the ...e5 and ...c5 breaks against d4 later. White's most frequent reply is 3. c4, which claims space on the queenside. 3. Bf4 and 3. e3 are also common and lead to quieter London- or Colle-style development. The engine's top choices are 3. e4, 3. Nc3 and 3. c4, and it gives White a slight edge, though results on Lichess are close to even.

The named continuation is the Robatsch Defense: Rossolimo Variation, 3. c4 Bg7 4. e4 Bg4. With White's broad pawn center in place, Black pins the f3-knight. The bishop then adds to the long-diagonal pressure of the g7-bishop against d4, and Black may consider giving up the bishop pair with ...Bxf3 to weaken White's grip on the center.