Best response to the Ruy Lopez: Berlin Defense (C65)

1. e4 e5 2. Nf3 Nc6 3. Bb5 Nf6 · White to move

What is the best response to the Ruy Lopez: Berlin Defense (1. e4 e5 2. Nf3 Nc6 3. Bb5 Nf6)? White to move. See the top replies ranked by opening theory and real-game results, starting with O-O.

The main theoretical reply is O-O, reaching the Ruy Lopez: Berlin Defense.