What cup size counts as kyonyu?

No distributor publishes a threshold. The tag is applied per release by marketing, and the same performer can be tagged kyonyu on one catalogue and not on another.

Is bakunyu bigger than kyonyu?

Yes, in the sense that bakunyu is used as the tier above. Where the line between them falls is not defined anywhere, so the relationship is ordinal rather than numeric.

Why does Japanese have a positive tag for small bust?

Because hinnyu functions as a genre category rather than a judgement. Japanese catalogues treat it as a preference shelf, the same way they treat the large-bust tiers.

Kyonyu, Bakunyu, Hinnyu: How Bust-Size Labels Work

Japanese bust-size tags are marketing tiers, not measurements. Kyonyu covers the broad large range, bakunyu marks the top of it and hinnyu the small end, but no distributor publishes the cup size where one tier becomes the next, so the boundaries move between catalogues.

Japanese bust-size tags are ordinal marketing tiers, not measurements. Kyonyu is the broad large band, bakunyu the tier above it, hinnyu the small band — and nowhere does a distributor publish the cup size at which one becomes the next.

That absence is the whole story. The tags are assigned per release by the people selling it, which means they are internally consistent within a catalogue and inconsistent across catalogues.

What are the tiers, in order?

Five terms cover almost everything you will see, and they can be arranged on one axis.

Term	Japanese	Literal sense	Position on the axis
Hinnyu	貧乳	"scant bust"	Small
Binyu	美乳	"beautiful bust"	Off-axis — shape, not size
Futsuu	普通	"ordinary"	Middle; rarely used as a tag
Kyonyu	巨乳	"giant bust"	Large — the broad default tier
Bakunyu	爆乳	"explosive bust"	The tier above kyonyu
Chobakunyu	超爆乳	"super explosive bust"	Intensifier on bakunyu

The binyu row is the one that catches people out. It is a compliment about shape and appearance and carries no size information at all, so a title tagged binyu could sit anywhere on the axis. English catalogues frequently translate it as if it belonged in the large tier, which it does not.

What does a bust tag signal when it appears in a title?

It signals that the release is being sold partly on that attribute. When the tag appears in the title text itself, rather than only in the tag list, the studio is telling you it is a primary selling point of the release.

This is a useful distinction to notice:

Where the tag appears	What it means
In the title text	A primary marketing angle for this release
In the tag list only	A descriptor for filtering, applied routinely
In a series name	The series is defined around it; every entry carries it

A performer who appears in a kyonyu-titled release is not thereby a "kyonyu performer" in any permanent sense — the label was attached to a product, and the next release may drop it entirely.

Do the labels map to actual cup sizes?

Not reliably. Catalogues that publish measurements do so in a separate field from the tag, and the two are set independently.

Our own records illustrate the gap. We hold cup-size values for 59% of named performers (our index, 2026-08 snapshot, n=2,333) — meaning that for over 40% there is no measurement recorded anywhere in our data, only whatever tags the source listing carried. A tag is often the only size signal that exists for a title, which is precisely why it cannot be treated as a measurement.

Boundary worth stating: our coverage is uneven and a large share of our representative images comes from a small number of sources, so what we can describe is how the labels appear in our sample, not how the industry as a whole applies them.

How do the English translations distort these?

By flattening a five-step ordinal scale into two or three English words.

English catalogues commonly use "big tits", "busty", "huge tits" and "big boobs" more or less interchangeably, with no stable mapping back to the Japanese tiers. The result is that kyonyu and bakunyu — which are genuinely different tiers in Japanese — routinely arrive in English under the same label, while binyu, which is not a size tag at all, gets swept into the same bucket.

The small end fares worse. Japanese hinnyu functions as a neutral preference category; English renderings sometimes carry a diminishing tone that the Japanese tag does not. The nearest neutral English equivalent is simply "small bust", and catalogues that use it are translating more faithfully than those reaching for something more colourful.

Which of these is worth learning first?

Three: kyonyu, bakunyu and hinnyu. Between them they account for the large majority of bust tagging you will encounter, and they establish the shape of the axis — broad large tier, top-of-range tier, small tier.

Add binyu fourth, specifically so you stop reading it as a size claim. That single correction removes more confusion than learning the intensifier forms above bakunyu.