> It’s definitely illegal, labor rights are pretty strong in Japan.

In some ways they are. Notably Japan has no concept of constructive dismissal, and companies have a pretty broad right to assign work and even to assign someone to work at a faraway office. There may be some anti-harassment law on the books, but it's very hard to get anything recognised under it, and if someone is just constantly assigned bad work, or no work, they have very little recourse.

And even if you could win a lawsuit, Japan doesn't do punitive damages or damages for emotional distress. So you'd be able to claim, maybe, lost wages for your time out of work, and... that's probably it.

Labor rights are far stronger in Japan than countries like the US, but like regulations everywhere, are only as strong as they are actively enforced, where companies suffer meaningful penalties for violating them. Japan is by no means a place where this is true, such that companies fear violating them.