Ruy Lopez long reign as World Champion". The main replies for Black are 4...d6 and 4...Bc5. In both cases, White commonly plays 5. c3. An uncommon and dubious reply is 4...Ne7, which tries to set up the Mortimer Trap. The Berlin is assigned "ECO" codes C65–C67. Code C65 covers alternatives to 4.0-0 as well as 4.0-0 Bc5. Code C66 covers 4.0-0 d6, while C67 is 4.0-0 Nxe4. Less-common third moves for Black: Ruy Lopez The Ruy Lopez (; ), also called the Spanish Opening or Spanish Game, is a chess opening characterised by the moves: The Ruy Lopez is named after 16th-century
Open Game and preparing for d2–d4. Black's most common reply is , which usually leads to the Ruy Lopez (3.Bb5), Italian Game (3.Bc4), or Scotch Game (3.d4), though 3.Nc3 Nf6 (the Four Knights Game), often played in the late 19th to early 20th century, or, less commonly, 3...g6 or ...Bb4, (the Three Knights Game), are other possibilities. If Black instead maintains symmetry and counterattacks White's center with then the Petrov's Defense will usually result, though White can avoid the extensive theory of the Petrov by playing 3.Nc3 if he wishes. The Philidor Defence, (2...d6), largely fell out of use after World War