>>2482214>>2482301https://en.wikipedia.org/wiki/Censorship_in_Japan#Pornography>its just too hard to believe that any country would have a law for this kind of stuff
Almost every country has "obscenity laws," which ideally exist as a legal representation of a society's collective desire to limit content deemed too obscene to justify its publication/sale/etc. Naturally, these laws are less than loved by all, and can be used to suppress things which were never intended to be affected. In fact, it used to be de-facto illegal to sell explicit pornography in the USA because of how states and the federal government enforced obscenity laws. And lolicon is effectively illegal in Australia, Canada, and the UK due to their interpretation of these laws.
Japan's post-war enforcement of these laws in regards to pornography has generally been much stricter than in the USA, with the exception of drawn depictions of children. Over time, these standards have been relaxed, to the point that genitalia censorship is only potentially enforced in works which are deemed to be pornographic in intent, rather than artistic. The degree of genitalia self-censorship also varies considerably, depending on which works have recently been deemed to be insufficiently censored.
Law enforcement generally does not go after those who freely distribute or self-publish, but the websites and conventions/stores which host these works may take their works down to avoid issues with law enforcement.
To compare/contrast, South Korea much more effectively bans all pornography and goes after independent/non-profit Korean artists, Taiwan has no mandated censorship but getting permission to sell pornography legally is a bitch (anecdote from a friend), and the PRC bans drawn pornography and gay/lesbian/etc works, but this is only enforced for works made and intended for Chinese audiences.