What are the rules for living in Japan?

Question:

In a about a year I plan on moving back to Japan , my home country to attend my old school, and my family need to stay in the US to support my grandmother with cancer, and my younger sister with her school. I want to attend my 2 last years of high school in Japan, and I realize I will be 16, and wont be able to live on my own. I have family in Tokyo, but they are 2 hours away from my school and I would have to get up at 4-5 am everyday . Is it legal to live with someone that is 18+ and not a relative? I have an older friend who will be 18 when I return, and she said I could move into her apartment, while she attends college, but I wanted to make sure. My question is: Is it legal to live with someone who is 18+ , but not family?

Answer:

It's of course legal for Japanese.

But if you are not Japanese, I don't think you can get a visa to live just by living with someone not your parents.