Ruy Lopez defense
|The Ruy Lopez (also called the "Spanish" opening) starts out as:
1. e4 e5 2. Nf3 Nc6 3. Bb5
The Ruy Lopez is an old opening; it is named after Ruy Lopez, a 16th Century Spanish clergyman and chess enthusiast. He made a systematic study of this and other chess openings, which he recorded in a 150 page book. However, although it is named after him, this particular opening was known earlier; it is included in the Gottengen manuscript, which dates from 1490. Popular use of the Ruy Lopez opening did not develop, however, until the mid 1800's when Jaenisch, a Russian theoretician, "rediscovered" its potential. The opening is still in active use; it is a favorite of Gary Kasparov and Bobby Fischer. In it, White creates a potential pin of the d-pawn or Knight and starts an attack immediately, while simultaneously preparing to castle.
White generally directs pressure on Black's e-pawn and tries to prepare for a pawn on d4. It's known that Black's best reply on move 3 is a6, which attacks White's attacking bishop. After that, White can back up (Ba4) or exchange pieces (Bxc6).source:http://www.dwheeler.com/chess openings/