Opening book is often used to describe the database of
chess opening
A chess opening or simply an opening is the initial stage of a chess game. It usually consists of established theory; the other phases are the middlegame and the endgame. Many opening sequences have standard names such as the "Sicilian Defens ...
s given to
computer chess programs (and related games, such as
computer shogi). Such programs are quite significantly enhanced through the provision of an electronic version of an
opening book
A chess opening book is a book on chess openings. This is by far the most common type of literature on chess. These books describe many major lines, like the Sicilian Defence, Ruy Lopez, and Queen's Gambit, as well many minor variations of the ma ...
. This eliminates the need for the program to calculate the best lines during approximately the first ten moves of the game, where the positions are extremely open-ended and thus computationally expensive to evaluate. As a result, it places the computer in a stronger position using considerably less resources than if it had to calculate the moves itself.
On some occasions, a player might consider playing a strange move outside the opening book to force a computer to think for itself. While this may introduce a strategic weakness, a lot of the time, playing out of the book early may end up compromising one's own pawn structure, losing a tempo or allow the opponent to develop more effectively, as chess engines have become significantly more powerful over time to think more deeply or accurately than in the past.
History
By 1977, 14 of 16 entries in the second
World Computer Chess Championship used opening books. One of the entries without a book, DARK HORSE, defeated opponent CHAOS in part by using a
nonstandard N-F3 opening.
Design
Modern chess engines are designed to be controlled by a graphical user interface such as
Winboard
XBoard is a graphical user interface chessboard for chess engines under the X Window System. It is developed and maintained as free software by the GNU project. WinBoard is a port of XBoard to run natively on Microsoft Windows.
Overview
Original ...
,
ChessBase or Arena through the
Universal Chess Interface protocol or Chess Engine Communication Protocol. In this case the opening book may often be specified in the GUI and then the GUI makes the moves from the opening book on behalf of the engine when the occasion arises.
Format
Opening books used by computers are often in a binary undocumented or PGN format. Examples are ChessBase's .ctg format or Pgn Format and Arena's .abk format. One notable exception is the Polyglot book format which is fully documented and which is being implemented in an increasing number of programs.
[http://hardy.uhasselt.be/Toga/book_format.html]
See also
* Chess opening
* ''Modern Chess Openings''
* ''Encyclopaedia of Chess Openings''
* List of chess books
* List of chess openings
*Chess engine
*Computer chess
*Computer shogi
* Shogi opening
*Endgame tablebase
* Chess endgame literature
References
{{Reflist
Chess openings, *Opening book
Chess databases
Bibliographies of games and sports, Chess
Shogi software