Ruy Lopez - modern Steinitz defence - 5.O-O
1. e4 e5 2. Nf3 Nc6 3. Bb5 a6 4. Ba4 d6 5. O-O
White advances the king's pawn to e4. Black advances the king's pawn to e5. White develops the knight to f3.
Black develops the knight to c6. White develops the light-squared bishop to b5. Black plays the a-pawn to a6.
White places the light-squared bishop to a4. Black plays the queen's pawn to d6. White castles kingside.