I know that bullying is universal worldwide, but the subculture around it differs, as in Japan it seems to be more psychological rather than physical, even if you stand out from the norm or customs.
For instance even you're not Japanese or mixed race (like that of another nationality), is a factor that can trigger bullying, you'll become bait for the tormentors. Seeking actual support is something they're afraid of as the bullies threaten the victim.
Also it does not help to how teachers or adults deal with it, they literally say amongst the lines of「無視」(ignore) Well... that will be useless when it's escalated to the breaking point. Teachers do not use the right approach, even in front of the entire class indirectly teasing or chastising him or her, there are cases that they are the bullies themselves or an accesssory.
Even if the victim reports it to both parents or the school body itself, most of the time it's brushed off as they don't give a f*ck about it, even at the most severe cases. A common outcome is that the victim ends up thinking about 自殺 (suicide) rather than actually dealing with it, the whole idea about it has been part of the culture for centuries due to seppuku.
In most cases, media only discusses it if the victim is deceased, when the school is questioned about it, they often say "We're not aware of it." When they were but decide to put it under the rug. Also, the mindset most people have is "Well... we're used to it. There's no point in reporting it when nothing is going to happen."
I've noticed that in both countries most of the tormentors are teenage girls rather than boys, they surround the victim trying to sway them away from anyone who can intervene. The subject matter of bullying in countries like Japan (or South Korea) is overlooked and brushed aside as they don't really address it sincerely, the stigma of mental health is dire as emotional weakness is frowned upon.