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
Tactical role-playing game to equip them, change classes, train them, depending on the game. A number of early role-playing video games used a tactical form of combat, such as "Tunnels of Doom" (1982) and "" (1983), as well as "The Dragon and Princess" (1982) and "Bokosuka Wars" (1983), which introduced party-based, tiled combat to America and Japan, respectively. Further, tactical RPGs are descendents of tabletop role-playing games and wargames, such as "Dungeons & Dragons" and "Chainmail", which were mainly tactical in their original form. Nevertheless, much of the development of tactical RPGs has diverged on each side of the Pacific, and the term