RN
The honest answer to the question in this article's title is that no law anywhere in Japan says to pixelate anything.
There is no statute specifying a mosaic. No regulation setting a block size. No agency issuing a technical standard for how thoroughly a body must be obscured. The blur that has defined Japanese adult video for half a century is not a legal requirement at all — it is an industry's collective guess about where a line sits, made repeatedly, by people who would rather guess conservatively than find out.
Once you know that, the rest of the subject stops being mysterious and starts being an unusually clear case study in how vague law actually operates.
What Article 175 says, and what it conspicuously does not
Article 175 of the Penal Code dates to 1907 and prohibits distributing, selling or publicly displaying obscene documents, drawings or objects. Penalties run to two years' imprisonment with labour, a fine of up to two and a half million yen, or a petty fine.
Now read it for what is absent. It does not define obscenity. It does not name body parts. It says nothing about mosaics, blurring, black bars, resolution or coverage. It gives no threshold, no safe harbour, and no way to check in advance whether what you are about to release crosses the line.
What filled that vacuum was case law and, far more consequentially, institutional caution. Courts developed a test through a small number of famous prosecutions across the twentieth century, and the practical understanding that settled out was that visible genitals and pubic hair in the context of a sexual act put a work at risk. Nobody legislated the mosaic. The industry inferred it.
The part everyone skips: the certification bodies
This is the mechanism, and it is why the mosaic is so consistent when the law behind it is so vague.
Japanese adult video has long operated through self-regulatory review organisations that screen material before release and certify that it meets their standards. NEVA — one of the oldest, formed in 1972 by major producers — is the usual example. These bodies publish guidelines that are stricter than the legal minimum, review submitted work, and issue a mark confirming compliance.
The enforcement is commercial rather than criminal. Distributors, rental chains, retailers and payment processors deal in certified product. Something without the mark does not get into the channel, which means it does not get made, which means the practical censor is a review committee rather than a prosecutor. Very few people in this industry have ever been near a courtroom. Nearly all of them have had notes returned on a mosaic.
That structure also explains the strangest observable feature of the whole thing: the mosaic has visibly changed over the decades — coarser in some eras, finer in others, applied to different parts at different times. A criminal statute from 1907 does not drift like that. A committee revising its own guidelines does. Reports of NEVA's August 2006 revision, which relaxed the treatment of pubic hair and updated mosaic standards, describe exactly that kind of adjustment.
The tradition story is backwards
The version this article replaces claimed the mosaic descends from centuries of Japanese modesty. That gets the history almost exactly the wrong way round.
Shunga — the erotic printmaking of the Edo period — is explicit, was produced by major artists, circulated widely, and depicts genitals without obstruction and frequently at exaggerated scale. Whatever else that tradition was, it was not squeamish.
The suppression arrives with the Meiji Restoration and the wholesale importation of Western legal and social norms in the late nineteenth century. Article 175 itself is a product of that period's legal modernisation, and the obscenity concept it encodes is a European transplant rather than a native inheritance. Shunga became contraband under a framework built to make Japan legible to Western powers.
So the correct sentence is the inverse of the popular one: explicit depiction is the older Japanese practice, and the censorship is the modern imposition. This matters beyond pedantry, because "it's their ancient culture" is the explanation that makes the whole arrangement seem natural and permanent, and it is not.
Two claims from the old article that are simply wrong
Drawings are not exempt. The original stated that hentai anime and manga sidestep censorship because no real person is involved. They do not, and anyone who has watched or read any is already aware that the mosaic is right there. Article 175 covers drawings explicitly — the word appears in the provision. In 2004 the anthology Misshitsu became the first manga obscenity prosecution, and the artist and publishers were convicted. Drawn work does have more room in some respects, which is why the ingenious workarounds exist, but the constraint is the same constraint.
Uncensored versions are not simply available domestically. The original described uncensored DVDs as readily obtainable and overseas-facing releases as routinely unpixelated. Distribution within Japan is the conduct Article 175 addresses, so uncensored material of Japanese production reaching viewers has historically involved routing around Japanese jurisdiction — offshore servers, offshore companies, offshore distribution. It is not a marketing option a domestic studio picks from a menu, and describing it as one misrepresents both the legal position and the people taking the risk.
What the article should have been about instead
Written in 2023, it missed the most consequential change to Japanese adult video in decades, which had already been in force for a year.
The AV Appearance Damage Prevention and Relief Act took effect in June 2022, in response to sustained reporting and campaigning about people who were pressured, deceived or contractually trapped into appearing in adult video. It is about consent rather than content, and it works through timing. A month must pass between signing a contract and filming. Four months must pass between filming and release. And a performer can cancel within a year of release, for any reason, without penalty.
The design intent is to remove the same-day signature followed by the same-day shoot, and to leave a person who changes their mind with a route out that does not depend on the goodwill of the company holding the footage.
It has not been uncontroversial among the people it governs. Performers have publicly protested aspects of it, arguing that the waiting periods disrupt production economics and cut the earnings of those working consensually and by choice. Both of those things can be true simultaneously — a protective measure can be genuinely necessary and still impose real costs on people who did not need protecting — and any honest account of Japanese AV regulation now has to hold both.
That is the live regulatory story. The pixels are the visible one, which is not the same thing.
About the "exotic East" framing
The old version leaned on a set of claims about Japanese adult content being defined by fantasy, submissiveness and sensuality as against Western hardcore directness. Those are marketing categories generalised into national character, and they describe what an international audience selects for far better than they describe an industry that produces an enormous and internally varied volume of work.
A genre distinction worth making would be about production structure, distribution channels and the certification regime described above. "Their women are submissive" is not a genre distinction. It is a stereotype with a search tag attached.
The short version
The mosaic is not the law. It is what an industry built to avoid ever meeting the law — a private certification system standing in front of a public statute nobody wants tested, doing its job so effectively that most viewers assume the blur is legally mandated.
Which is, in the end, the more interesting answer. If you want to see how the drawn side of it works around the same constraint, the hentai section is where that ingenuity is on display, and it is worth watching for the workarounds rather than despite them.