CTG

toc
 * Home * Knowledge * Opening Book * CTG**

an opening book format by ChessBase, supported by their Fritz GUI and ChessBase GUI, and therefor used by all chess engines compatible with these commercial user interfaces. While the book format is proprietary, a partial specification was leaked for the purpose of interoperability. Each Chessbase book consists of four files, the binary **CTG** file contains the real data, the **INI** text file provides auxilliary information, the **CTB** file some kind of bitmap over free pages in the CTG file, and the **CTO** file, containing a lookup table into the CTG file for fast indexed access.
 * CTG**, (ChessBase Opening Tree of Games)

Only White to move positions along with its moves, annotations and engine recommendations, and statistics are stored, probing black positions requires color flipping, of course including en passant square and castling rigths. Further, if the white king is on files a-d, and neither side has any castling rights remaining, the board is mirrored horizontally. The CTG file is organized in 4KiB pages, the first page contains header information such as the number of games, followed by consecutive data pages. Each data page starts with an header specifying the number of positions and bytes per page, followed by a list of a variable length position entries.

=See also=
 * ABK - Arena's book format
 * BIN - Polyglot book format

=Open Source Engines=
 * Brutus
 * Daydreamer

=Forum Posts=
 * [|CTG specification] by Sesse, Rybka Forum, September 30, 2007
 * [|Brutus v8.5 released] by Stephan Vermeire, Winboard Forum, January 25, 2010 » Brutus
 * [|CTG to polyglot format] by matematiko, Winboard Forum, October 23, 2013 » Polyglot
 * [|My new book is out: Noomen.ctg] by Jeroen Noomen, CCC, May 22, 2016
 * [|Scid / Scid vs. PC - ChessBase (.ctg) and Arena (.abk)] by Norbert Raimund Leisner, CCC, August 19, 2016 » ABK, Scid
 * [|Noomen.ctg: UPDATE] by Jeroen Noomen, CCC, August 20, 2016

=External Links=
 * [|Free Opening Book Downloads] from HIARCS Chess Software
 * [|Opening Books] hosted by Ed Schröder
 * [|GitHub - sshivaji/ctgexporter: Converter for the CTG chess format. Export CTG to polyglot and other formats] by Shivkumar Shivaji

=References= =What links here?= include component="backlinks" page="CTG" limit="80"
 * Up one Level**