Never mind that Tendo was the daughter of a Yakuza; she barely sees her father as a child. When she does see him, he's a violent, roaring monster. He beats his wife and kids when he's drunk, he beats them when he's sober, he beats them when there's nothing else for him to do.
Tendo, meanwhile, is an outcast in her neighborhood. The Yakuza aren't folk heroes in Japan the way Mafioso are in the USA, and this poor little girl is ostracized everywhere by people who despise her father. What they haven't got the guts to say/do to her father, they say/do to her. And so do there children.
You can guess what comes next; truancy, drug use, sex addiction, self-destructive behavior, abusive boyfriends, running around with men who use her and treat her like dirt. Worse, Japan's had no child-welfare system when she was growing up, at least not like the kind in Europe and the USA. This girl was driven from the home by her father's savage abuse, yet there was nobody to stick up for her. Nobody blamed her parents.
The ending is a happy one, fortunately. She does have a career, has a child, tattoos herself (as a way of gaining control of her body) and makes her peace with life.
You have to give her credit for one thing; she did and excellent job writing the book, considering this woman has a 6th grade education.