Since the mid-1980s, items made for the Japanese market are subject to labeling requirements documented in the RIAJ's RIS 204 standard. Helpfully for collectors, the requirements include the actual release date of the item. Japan is the only place in the world which has release dates printed on almost all recorded music products.
Sometimes there is only one date code, sometimes there are several. They are usually found on back cover and/or the obi (outer paper strip/U-card near the spine).
The formats have changed several times, and record companies are not consistent in how closely they follow the standard, so it is likely that only some of the information will be on a particular release. Sometimes there is no release date code at all.
Japanese date formats are always year, then month, then day, separated by middle dots (·), bullets (•), or periods (.).
The years 1984 through 1991 may be denoted by a code based on the phrase "Nihon Record", but they didn't use "n" twice, and they mostly stopped after "c":
Example: O•2•25 means the 25th day of February, 1987.
Otherwise, the year is usually 2 digits, e.g. 95 for 1995, 02 for 2002. It could be four digits (unconfirmed). The month and day are usually one or two digits each.
Example: 97·9·24 means the 24th day of September, 1997.
These codes appear next to the release date(s), and affect the rental prohibition period; see below.
It is unknown when these codes started to be used, but they usually appear right next to the release date.
Sometimes the Japanese release date is listed next to another date in parentheses. They may appear in a box together.
The first date is the release date for this item in Japan, and the date in parentheses is the original release date of the audio content (but not this item!) for the rest of the world.
This second date is only on releases which contain material licensed from a foreign record company. Essentially, it is a more specific version of the phonographic copyright, and is needed so that the rental prohibition period (see below) can be determined. It is not the release date of this record or CD, it is just when an equivalent foreign item was first available somewhere in the world.
Example (as seen here): "95·9·25 (95·8·7)" means this item was released in Japan on 25 September 1995, but the audio was first released in the rest of the world on another item on 7 August 1995.
The second date may not really be an accurate debut release date for the entire world, but rather just a date supplied by the foreign record company the music was licensed from, applicable only to their market.
Rental of records and CDs is illegal in most of the world, but it has been legal in Japan since 1985. The shops must pay a fee to copyright owners, and they must honor a temporary ban on renting new releases. For music of foreign origin (see Ⓨ above), there is an automatic ban of 1 year after the worldwide release date. Thus:
Example: "95·9·25 (95·8·7) ⓎⓍ" means released in Japan on 25 September 1995, audio released on another item elsewhere on 7 August 1995, the music is of foreign origin, and rental is prohibited for one year from 7 August 1995 (so, through 6 August 1996). (source)
Example: "X~88·2·24 O·2·25" means released in Japan on 25 February 1987, and rental is prohibited through 24 February 1988. (source)
For music of Japanese origin (see Ⓛ above), the rental ban period is often unspecified on the item, but by law, is known to vary within these limits:
It is unknown when this mark started to appear on releases.
Example: ¥2,300 or 2,300円 means 2300 yen.
Consumer-tax started in Japan on April 1, 1989 and all CDs which were sold after the day have 2 prices: there was a new requirement that music be marked with two prices (pre-tax and post-tax) instead of one. If only one price is mentioned, it's a release from before that date.
1980s major-label CDs often included an indication of the original retail price in their catalog number, with a change from 35 to 32 reflecting a price drop from ¥3500 to ¥3200 in 1985. However, the catalog number sometimes did not change on later pressings which had lower prices printed elsewhere.
The encircled 再 (sai) character is used on music and print publications to represent saihan seido (a.k.a. saihanbai kakaku iji seido), Japan's resale price maintenance system. It normally accompanies a date and the phrase "まで", meaning "until", in order to indicate the first date the item can be returned for credit or sold at a discounted price. It can also appear next to the price to be maintained.
Example: 再95.7.20まで means that price must not be discounted before July 20, 1995.
Unlike a copyright date, the saihan seido date is normally in the future, a certain number of months or years beyond the release
(As of 2017, most font renderers still have trouble doing circle overlays, but if it works in your browser, this will be the encircled character: 再⃝)
Many Japanese promos come in retail packages, so the release dates printed on those items should not be considered applicable to the promo.
Reissues and represses do not always have updated dates, so if there is reason to doubt a printed date, don't use it.
Items manufactured in Japan normally have a Japanese Article Number (JAN), which is an EAN-13 barcode. It begins with 49 or 45.
It is unknown when the recording industry in particular adopted barcodes, but the use of JAN in Japan began in 1978.
xxxxx or xxxxxxx is the GS1-assigned maker/manufacturer code, n is the maker's arbitrary item/product code, and y is a calculated check digit.
In Japan, an OCR-based system was used before the widespread adoption of EAN barcodes. For compatibility, the human-readable digits below the EAN are normally written in an OCR-friendly font and are prefaced with "T" so the OCR systems know the code has 13 digits (T for thirteen, F for five).
This is not specific to Japan:
Ideally, the phonographic copyright date is the global public debut of the recording in any form, but record companies are inconsistent and make mistakes, so it could be a different date for a particular mastering, edit, or remix, or the date could only be applicable to the referenced company or market.
Simply being manufactured in Japan does not mean a release was made for Japan. For example, many 1980s CDs were pressed in Japan strictly for export and release in the West because there were very few CD pressing plants anywhere in the world at that time. These releases generally do not have any Japanese text on them, no special inserts or obi, and no mention of Japanese record companies or rights societies. Do not expect to see release dates on these items.
Most of the info here was authored by Discogs user mjb based on these sources:
A couple pieces of info come from this vendor's website:
Forum discussion has helped as well:
The barcode info is gleaned from various web pages and documents at GS1 Japan.