Q:

Is it common for Japanese school kids to live alone IRL?

In so many animes, I have noticed that middle- and high-school kids live by themselves without any adults around to supervise. While this may serve as a useful plot device, I noticed that it happens far too often. Arima Kousei of Your Lie in April lives alone because his father is always out on business trips, Sakuta Azusagawa (Rascal Does Not Dream of Bunny Girl Senpai) and Kyon (Haruhi Suzumiya series) live with their younger sisters. Other characters of Haruhi Suzumiya like Yuki Nagato and Ryoko Asakura, both functionally human to that society, also live by themselves. Is that common in Japanese society?
[Having lived in multiple cities across multiple countries, I have never seen school kids living alone in houses like that. The best I've seen within the budget of older university students are single-room apartments or shared houses.]
Ideally, I'm looking for answers from people who have first-hand experience of school life in Japan. Answers based on studies and reports would be OK too, if you can translate the relevant information to English.

A:

I wouldn't call it common, based on the data I've found, but the situation commonly portrayed in anime, manga and light novels are not unheard of in real life.
According to this study, those aged 15-19 that live alone comprises only about 5% of the population. It's worth nothing that the graph peaks at the age ranges of 20-24 and 80-84. So while there are indeed students living alone in real life, it's not as common as anime, manga or light novels make it to be.
There are also some discussion about this on different sites, some who've had Japanese friends who live alone. Here are some links if you'd like to read about their experiences. Link 1, Link 2, Link 3

