The Ruy Lopez opening is a well known chess opening strategy and very popular. It starts with 1 e4 e5 2.Nf3 Nc6 3.Bb5 and has a lot of variations. This opening was first developed by Ruy Lopez (1540 – 1580), a Spanish priest and a bishop in segura, who wrote articles about chess. Black has various defences now:
The most popular move is 3...a6
There are other defences like: 3...Nge7 (Cozio) 3...Nd4 (Bird) 3...d6 (Steinitz) 3...f5!? (Schliemann) 3...g6 (Smyslov) 3...Nf6 (Berlin) 3...Bc5 (Classical or Cordel variation)
I personally like the Classical or Cordel Variation very much as the black bishop moves to the strong square c5 and puts pressure on f2.