ChessBase CKO

Last month an intriguing comment appeared against an old post on my main blog, A Database of Chess960 Start Positions (December 2008). It said,

I'm looking for a key file (*.CKO) to use with base of games chess 960 with ChessBase 14.

Since the last time I used ChessBase software was, well, never, I first had to decipher the request. What's a *.CKO file?

I already knew that ChessBase management is no fan of chess960; see Purported Problems with Chess960 (April 2018) for the nitty gritty. If that isn't convincing, the user manual for Fritz 18 has a little more than one page out of 425 on Fischer's greatest invention, titled '3.2.10 Chess 960'. The space in front of '960' pretty much guarantees that it will never be found in any normal search. The page instructs you to 'pick a number for one of the predefined Fischer-Random positions', i.e. no built-in random position generator. After that,

Games you have played against the program are saved in the file Autosave-960.cbh in the users folder. Saved Chess 960 games in a database are given with the number of the predefined position with which they were played.

Back to *.CKO files, the best explanation I could find was ChessBase Support - Details : A tip for Full Analysis. It starts,

The function "Full analysis" on Fritz & Co produces a complete analysis of one or several games, including variations, textual commentary and even opening references. The analysis also contains indications of games which were played with that opening system.

For 'indications of games', I understand 'references to games' from another Chessbase database. The explanation continues,

With the help of a large reference database the program is able to classify the opening played in the game, integrate recent games for comparison and indicate the position at which the game being analysed diverges from opening theory.

How does that work?

If no openings key is present in the database you have defined as your reference database, the program cannot produce a reference. [...] If there should be no openings classification, the program automatically offers to classify them by means of a pre-existing key. [...] An openings key always has the file extension *.CKO.

Bingo. A chess960 CKO file would somehow index the 960 start positions. I also found references to a Chessbase CPO file ('positions, openings'). This might serve the same purpose for chess960 as a CKO file, although actionable information on this filetype was even sparser than for the CKO extension.

Will ChessBase someday offer a CKO/CPO solution for chess960? Maybe, but I wouldn't bet any money on it. If the company doesn't see a need to offer a random position at the start of a chess960 game, it won't see a need for more sophisticated functionality.