A chess opening is the group of initial moves of a chess game. Recognized sequences of opening moves are referred to as openings as finished by White or defenses, as finished by Black, but opening is also used as the general term. There are many dozens of different openings, and hundreds of named variants. The Oxford Companion to Chess lists 1,327 named openings and variants. These vary widely in character from quiet positional play to wild tactical play. In addition to referring to specific move sequences, the opening is the first phase of a chess game, the other phases being the middlegame and the endgame.
A sequence of opening moves that is considered standard (often cataloged in a reference work such as the Encyclopedia of Chess Openings) is referred to as "the book moves", or simply "book". These reference works often present these move sequences in simple algebraic notation, opening trees, or theory tables. When a game begins to deviate from known opening theory, the players are said to be "out of book". In some opening lines, the moves considered best for both sides have been worked out for twenty to twenty-five moves or more. Some analysis goes to thirty or thirty-five moves, as in the classical King's Indian Defense and in the Sveshnikov and Najdorf variations of the Sicilian Defense. Professional chess players spend years studying openings, and continue doing so throughout their careers, as opening theory continues to evolve. Players at the club level also study openings but the importance of the opening phase is smaller there since games are rarely decided in the opening. The study of openings can become unbalanced if it is to the exclusion of tactical training and middlegame and endgame strategy.
A new sequence of moves in the opening is referred to as a "theoretical novelty". When kept secret until used in a competitive game it is often known as a "prepared variation", a powerful weapon in top-class competition.
Famous quotes containing the words chess and/or opening:
“What have we achieved in mowing down mountain ranges, harnessing the energy of mighty rivers, or moving whole populations about like chess pieces, if we ourselves remain the same restless, miserable, frustrated creatures we were before? To call such activity progress is utter delusion. We may succeed in altering the face of the earth until it is unrecognizable even to the Creator, but if we are unaffected wherein lies the meaning?”
—Henry Miller (18911980)
“Dentopedalogy is the science of opening your mouth and putting your foot in it. Ive been practising it for years.”
—Prince Philip (b. 1921)