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 defenses now.
See chess position below:
The most popular chess 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)
Study variations played with the most occurring 3...a6. 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.
Most popular setup is 3...a6 4. Ba4 - see video
Ruy Lopez - Games
I recommend
If you don't know which variation to play as Black then I recommend the Open Defense. It has been played in world championships in the past and is solid.
You have always "something" as Black to counter the white ideas and the setup is fairly clear and straightforward. Replay game 66 above and others to see how this opening variation is played. See basic position below