Is teenage violence normal in Japanese culture?

Question:

Right now I am an exchange student in Japan and everything is well, different. Yeah I know Japan is more traditional than say, other western countires having grown up in South Africa and then moving to New Zealand Iam quite capable of understanding both types.

So, one day I was at high school and this girl was having an argument with her bf. Pretty weird as people don't tend to do that here. So they dissapear and later reappear. His shoving her by her neck forward. She breaks away and falls against the wall. He comes at her again snatches her phone from her and with his free hand hits her over the head. I am standing in a crowded room with about 40 people. Boys and girls. No one notices and those that do, pretend not to. Now, Iam staring and waiting, looking for someone to do something.

He comes at her again chokes her, realises that they're in view of everyone else. He shoves her into the bathroom and she falls. I can see her legs sticking out in the corridoor. He starts kicking her. By now Iam expecting someone to stop him, no one does anything. I step forward but hold back thinking me being a girl myself who's to say he won't do the same to me and then what? What if no one stops him, what if no one helps me? So to my complete shame I stand and watch as he lands a few more kicks, turns toward the crowd to see of anyone will say anything, no one makes eye contact. I hold my gaze but as he comes near me I lower it. WTF is wrong with me? The girl gets up, she's ashamed, not crying but humiliated as she runs after him like a guilty child.

This stayed with me. I being the independant person that I am I cannot pathom anyone allowing that. And at her age as well, 17 years old. And I let it happen. For all my strength and self assuredness I experienced for this first time what it's like to be held back, quiet for being a girl. If it were New Zealand or South Africa I could open my mouth and say what I want and if he wanted to take a swing at me, no one would allow it. So, is this normal in Japanese culture? I can't get over it. Iam just as bad as he is because I watched, I watched him kick her while she was down. Like she were nothing.

Answer:

It's not normal. Personally, I have not seen it. Nor have I kicked a girl.

One possibility is that he's a sort of boss there whom everyone is scared of. But I'm not sure.