Do studios ever add these suffixes themselves?

Not in this form. Studios distinguish editions by issuing a separate catalogue number, not by appending a letter, so a suffix on a code is a strong signal the file passed through a redistributor.

Does -C always mean Chinese subtitles?

In practice it usually does, because the convention comes from Chinese-language subtitle groups. It is not a standard, though, and the same letter is occasionally used for other meanings such as a disc part.

Should I include the suffix when I search?

No. Catalogues index releases, not files, so a suffix guarantees an exact match will fail. Search the bare code first and treat the suffix as a separate filter afterwards.

What Do the Suffixes -C, -U and -4K Mean?

Suffixes attached to a JAV code describe a file rather than a release: -C marks a third-party subtitled copy, -U marks a copy claimed to be uncensored, and -4K claims a resolution. None are issued by the studio, and none are verifiable from the file name alone.

Suffixes attached to a JAV code describe a file, not a release. -C marks a copy with third-party subtitles, -U marks a copy claimed to be uncensored, and -4K claims a resolution. None of them are issued by the studio, none appear on the original cover, and none can be verified from the name.

This is the single most useful thing to understand about them: a studio that wants to distinguish two editions issues a second catalogue number. It does not append a letter. So the moment you see a suffix, you know the file has been through at least one redistributor.

What does each common suffix mean?

The suffix vocabulary is informal but fairly consistent across sources.

Suffix	Usual meaning	Added by	Verifiable from the name?
`-C`	Third-party subtitles, usually Chinese	Subtitle groups	No
`-CH`, `-SUB`	Same as `-C`, alternate conventions	Subtitle groups	No
`-U`	Claimed uncensored version	Redistributors	No
`-UC`	Claimed uncensored and subtitled	Redistributors	No
`-4K`	Claimed 2160p encode	Whoever encoded the file	No
`-FHD`, `-HD`	Claimed 1080p / 720p encode	Whoever encoded the file	No
`-A`, `-B`, `-CD1`	A file split into parts	Whoever split it	Yes, structurally
`-BEST`	Part of a compilation	Sometimes the label	Sometimes
Leading site tags	Distribution watermarking	Mirrors and aggregators	Irrelevant

Only the split markers describe something structural, and even those describe how the file was cut rather than how the title was released.

Why is -C the most reliable of the three?

Because subtitles are additive and self-evident: either a track is there or it is not, and you find out in seconds.

-C originates with Chinese-language subtitle groups, who took an untranslated release, produced a subtitle track and re-released the file under the original code plus a marker. The claim being made is narrow — "this copy has subtitles attached" — and it is easy to check.

What -C does not tell you is quality. Subtitle tracks range from careful human translation to machine output with no timing pass, and the marker is identical either way. It also does not tell you whether the subtitles are burned into the video or supplied as a separate file, which matters if you want to turn them off.

What does -U actually claim?

-U claims the copy has no mosaic, and it is the suffix most often attached to something that does not match the claim.

Three quite different things circulate under this marker:

A release that was published without mosaic in the first place, from a platform that does not apply it
A leaked master of a title that was published with mosaic
A file that has been processed after the fact to reduce the appearance of mosaic

The three are indistinguishable from the file name and very distinguishable on screen. The third category in particular produces visible artefacts, because the information removed by mosaicing is not recoverable — any process claiming to restore it is inventing detail rather than retrieving it.

Note also that -U is not how legitimately uncensored catalogues number their own releases. Those platforms use date-based codes with no suffix at all, which is covered in how uncensored releases are numbered.

Why is -4K the least trustworthy suffix?

Because resolution is trivially claimable and frequently upscaled, and the file name carries no evidence either way.

A 1080p source can be resized to 2160p in a few minutes. The resulting file is genuinely 3840×2160 by its metadata, contains no additional detail, and is usually larger than the original — so both the label and the file size support the claim while the picture does not. Bitrate is the more informative number, and it is exactly the number that never appears in the file name.

Treat -4K as "somebody encoded this at 2160p", which is all it can honestly mean.

How do split-file markers differ from the rest?

They describe how one release was divided into files, and they are the only suffix family that is structurally reliable.

Marker	Meaning
`-A` / `-B`	Two halves of one release
`-CD1` / `-CD2`	Same, older naming convention
`-part1` / `-part2`	Same, explicit
Consecutive codes	Two genuinely separate releases, not parts

The distinction that matters: ABF-042-A and ABF-042-B are one title in two files. ABF-042 and ABF-043 are two different titles. Multi-disc retail sets are numbered the second way, not the first, so a letter suffix almost always indicates a file split introduced downstream.

How should suffixes change the way you search?

Strip them, search the bare code, and reapply the suffix only as a filter.

The rule follows directly from what catalogues index. A storefront's database contains ABF-042 because that is what the label issued. It contains no record of -C, -U or -4K variants, because those are not products it sells. An exact-match search on the suffixed string therefore returns nothing, and the failure looks like the code being wrong when the code is fine.

The practical sequence:

Remove leading site tags and domains
Remove trailing language, quality and processing markers
Search the bare PREFIX-NUMBER
Once you have identified the release, look for the specific version you want

If the bare code still fails, the problem is elsewhere — see JAV code not found.

What if the suffix is all you have to go on?

Then the name has stopped being evidence, and the frame is the better identifier.

A heavily suffixed file name is a record of how many hands the file has passed through, not of what it contains. When you cannot trust the name, matching a face from a still sidesteps it entirely: our index compares 512-dimension ArcFace vectors across 241,792 indexed faces and 2,333 named performers (our index, 2026-08 snapshot).

Boundary worth stating: face matching identifies a person, not an edition. It cannot tell you whether the copy you have is subtitled, uncensored or genuinely 4K — those are properties of a file, and the only way to check them is to open it.