.CTB file extension

This is the basic program to work with .CTB extension

ChessBase Light 2007 ChessBase openings book

The program works with the following extensions: ck2, cbs, ck3, cko, cba, ckn, cbb, cp1, cbc, cp2, cbe, cp3, cbf, cpn, cpo, cbh, ctb, cbm, ctg, cbp, cto, cbt, pgi, cbv, pgn, cib, cbz, cit, ck1 and cbgi

.CTB extension is also supported by the following programs:

ChessBase 9 ChessBase openings book

ChessBase ChessBase openings book

ChessBase 13 is a personal, stand-alone chess database.

ChessBase Reader ChessBase openings book

Open chess games database files and play through the games.