.CKO file extension

This is the basic program to work with .CKO extension

ChessBase Light 2007

ChessBase Light 2007 ChessBase Opening Key

The program works with the following extensions: cbs, ck2, cko, ck3, 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

.CKO extension is also supported by the following programs:

ChessBase 9

ChessBase 9 ChessBase Opening Key


ChessBase ChessBase Opening Key

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

ChessBase Reader ChessBase Opening Key

Read chess games written in various formats and display them on a chess board.