Chess opening are so complex and theoretical that amateur players will have trouble understanding them. An example is the Perenyi Attack of the Sicilian Defense (see diagram) which yields an immensely complicated and tactical position that even strong players have difficulty handling, and that is beyond the comprehension of most amateurs. Major changes in the rules of chess in the late fifteenth century increased the speed of the game, consequently emphasizing the importance of opening study. Thus, early chess books, such as the 1497 text of Luis Ramirez de Lucena, present opening analysis, as does Pedro Damiano (1512), and Ruy López de
Ruy Lopez move carries no immediate threat, Black can respond in a wide variety of ways. Traditionally, White's objective in playing the Ruy Lopez is to spoil Black's pawn structure; either way Black recaptures following the exchange on c6 will have negative features for him, though he thereby gains the . However, in modern practice, White does not always exchange bishop for knight on c6, preferring the retreat 4. Ba4 if chased by 3...a6. The theory of the Ruy Lopez is the most extensively developed of all open games, with some lines having been analysed well beyond move thirty. At nearly every