Ruy Lopez - Treybal (Bayreuth) variation (exchange var. deferred)
1. e4 e5 2. Nf3 Nc6 3. Bb5 a6 4. Ba4 Nf6 5. Bxc6
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 develops the light-squared bishop to b5. Black pushes the a-pawn to a6.
White deploys the light-squared bishop to a4. Black transfers the knight to f6. White captures with the light-squared bishop on c6.