Japan is complicated. Here's a story from the Guardian that seems not to involve prostitution, but is nevertheless sex related (and child related).
Schoolgirls for sale: why Tokyo struggles to stop the 'JK business'
The persistent practice of paying underage girls for sex-related services, known in Japan as the ‘JK’ business, has seen charities step in where police have come up short
"Tokyo is famous for its fairly wild red light scene. You can find anything from a handsome man to make you cry and wipe away your tears to a maid to pour your drinks and giggle at your jokes and an encounter in one of the notorious “soapland” brothels.
"You can also pay to spend time with a schoolgirl. Services might include a chat over a cup of tea, a walk in the park or perhaps a photograph – with some places offering rather more intimate options.
...
"The fetishisation of Japanese schoolgirls in Japanese culture has been linked by some academics to a 1985 song called Please Don’t Take Off My School Uniform, released by the female idol group O-nyanko Club, and re-released by no less mainstream a group than AKB48, one of the highest-earning musical performers in Japan and whose single Teacher Teacher sold more than 3m copies in 2018.
"The term “JK business” has become a catch-all for cafes, shops and online agencies which provide a range of “activities”, many of which are not overtly sexual. Young women in school uniforms can be offered for reflexology and massage treatments, photography sessions and “workshops” in which girls reveal glimpses of their underwear as they sit folding origami or creating jewellery.
...
"Japan’s anti-prostitution laws broadly prohibit the sale and purchase of sex, but there are significant loopholes, of which establishments such as soaplands take full advantage. Crucially, in the case of JK businesses, Japan has no specific anti-trafficking laws in place. Ordinarily, a child under 18 involved in sex work is automatically considered trafficked, with harsh penalties for those responsible.
"Pornography laws relating to children are also limited – they do not, for example, cover manga, anime, or virtually created content, allowing games such as 2006’s controversial (and now no longer available) RapeLay, in which the player stalks and attempts to rape a single mother and her two school-age daughters."
Schoolgirls for sale: why Tokyo struggles to stop the 'JK business'
The persistent practice of paying underage girls for sex-related services, known in Japan as the ‘JK’ business, has seen charities step in where police have come up short
"Tokyo is famous for its fairly wild red light scene. You can find anything from a handsome man to make you cry and wipe away your tears to a maid to pour your drinks and giggle at your jokes and an encounter in one of the notorious “soapland” brothels.
"You can also pay to spend time with a schoolgirl. Services might include a chat over a cup of tea, a walk in the park or perhaps a photograph – with some places offering rather more intimate options.
...
"The fetishisation of Japanese schoolgirls in Japanese culture has been linked by some academics to a 1985 song called Please Don’t Take Off My School Uniform, released by the female idol group O-nyanko Club, and re-released by no less mainstream a group than AKB48, one of the highest-earning musical performers in Japan and whose single Teacher Teacher sold more than 3m copies in 2018.
"The term “JK business” has become a catch-all for cafes, shops and online agencies which provide a range of “activities”, many of which are not overtly sexual. Young women in school uniforms can be offered for reflexology and massage treatments, photography sessions and “workshops” in which girls reveal glimpses of their underwear as they sit folding origami or creating jewellery.
...
"Japan’s anti-prostitution laws broadly prohibit the sale and purchase of sex, but there are significant loopholes, of which establishments such as soaplands take full advantage. Crucially, in the case of JK businesses, Japan has no specific anti-trafficking laws in place. Ordinarily, a child under 18 involved in sex work is automatically considered trafficked, with harsh penalties for those responsible.
"Pornography laws relating to children are also limited – they do not, for example, cover manga, anime, or virtually created content, allowing games such as 2006’s controversial (and now no longer available) RapeLay, in which the player stalks and attempts to rape a single mother and her two school-age daughters."