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

On a humid Wednesday night the streets of Kabukicho, Tokyo’s most famous red light district, hum with people. Some are tourists, here to gawp and take selfies, but others are customers. Adverts for clubs flash and sing and girls dressed as maids hold signs offering deals for local bars.

In a grubby shopfront a perky cartoon featuring a cute Mr Men-style creature offers part-time work. The ad, which has an alarmingly catchy jingle, doesn’t specify what the work is, but it doesn’t need to: the answer is all around us on the brightly lit billboards advertising the charms of male and female bar hosts.

We almost allow men to say ‘yeah, I’m attracted to young children’

As Japan's capital enters a year in the spotlight, from the Rugby World up to the 2020 Olympics, Guardian Cities is spending a week reporting live from the largest megacity on Earth. Despite being the world's riskiest place – with 37 million people vulnerable to tsunami, flooding and due a potentially catastrophic earthquake – it is also one of the most resilient, both in its hi-tech design and its pragmatic social structure. Using manga, photography, film and a group of salarimen rappers, we'll hear from the locals how they feel about their famously impenetrable city finally embracing its global crown

A society that commercialises and consumes underage women as a sexually high-value commodity has a problem

Related: 'There are almost no women in power': Tokyo's female workers demand change