Concord Jazz

See Concord Records for this label history.
Concord Jazz apparently historically used cat # as follow:
CJ-###-X
where CJ stands obviously for Concord Jazz, ### a three digit number, and possibly X=C for cassette, possibly others letters.
At some point when Concord grew up, they unified all their releases cat # to a new scheme:
CCD-#### and/or CCD-####-2
The CCD part indicates a Concord CD, and the four digit number "extends" the historical catalog codes (eg: CJ-287-C is reissued as CCD-4287).
All this is (yet) speculative though, so take it with some salt.