A Man With No Talents: Memoirs of a Tokyo Day Laborer by Oyama Shiro. This book provides a different perspective on Japanese society. It's written by a man who got a degree, became a salary man and realized that he hated everything about it. He quits and becomes a day laborer. By the time he has written this book he is in his fifties I believe. Anyway, give it a try. It's a short book and easy to read.
A while back, I spent a week in what's widely considered the 'bad part of town' in Tokyo -- up around Minami-senju, Kita-senju, the area once known as Sanya, the subject of the famous book "a man with no talents" (https://www.amazon.com/Man-No-Talents-Memoirs-Laborer/dp/080144375X).
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Shit was charming as hell. As low-income areas in the world go, it was nicer than most of San Francisco's yuppie areas. I saw maybe one daytime alcoholic. That's about it.
I'm not sure why you picked Tokyo, but you're making an easy project very hard for yourself.