How CD catalogue numbers work
A catalogue number is the closest thing a CD has to a serial number. Learn to read it and you stop buying the wrong edition.
Anatomy of a cat no
Most catalogue numbers are a label prefix plus a serial, sometimes with a format or territory suffix. The prefix identifies the label or series; the serial places the release in that series; a trailing digit or letter often marks the format (CD vs cassette) or a repress.
Territory patterns worth knowing
Japanese numbers use short alphabetic prefixes tied to the label and era — TOCP for Toshiba-EMI, SRCS for Sony, VJCP for Victor, ESCA for Epic Sony. European majors lean on numeric strings with a two-digit format code. US pressings often reuse the LP number with a CD prefix appended.
Prefix changes over time are useful dating tools: the same album can carry three different Japanese numbers across a decade of repressings.
Reissues, repressings and suffixes
A reissue almost always gets a new number. Where it doesn't, look for a suffix or an added letter. If a seller quotes only the album name, ask for the number printed on the spine — that's the only reliable way to know whether you're getting the 1987 original or the 2011 remaster.
How we use them
Product URLs and titles on SideOne include the edition or catalogue number wherever it distinguishes a pressing, so a search for a specific cat no lands on the exact copy rather than a generic album page.