Four knights - Spanish variation
1. e4 e5 2. Nf3 Nc6 3. Nc3 Nf6 4. Bb5
White plays the king's pawn to e4. Black plays the king's pawn to e5. White develops the knight to f3.
Black develops the knight to c6. White jumps the knight to c3. Black moves the knight to f6.
White develops the light-squared bishop to b5.