Philidor - Nimzovich (Jaenisch) variation
1. e4 e5 2. Nf3 d6 3. d4 Nf6
White pushes the king's pawn to e4. Black advances the king's pawn to e5. White develops the knight to f3.
Black advances the queen's pawn to d6. White moves the queen's pawn to d4. Black develops the knight to f6.