company wants to pay high hourly wage for “28 hours” but expect full-time work

My husband recently got a job offer in Japan and we’re trying to understand the legal and tax implications.

He currently has a dependent visa valid for three years. The company wants him to work 9:00–18:00, which is essentially a full-time schedule. However, they said they don’t want to sponsor or change his visa right now.

Instead, what they proposed is this:
They will officially register him as a part-time worker limited to 28 hours per week (since that is the usual limit for dependents). But to compensate for the reduced recorded hours, they plan to increase the hourly wage to 2000 yen so that his monthly income is roughly around ¥200,000, which is similar to what he would earn if it were a normal full-time job.

So on paper it looks like 28 hours of work, but in reality the schedule would be 9–6 like a full-time job.

They said that after some time, once they see how he performs, there is a possibility that they might help change his visa status to a proper work visa, but for now they want to keep it this way.

This job also didn’t come through a formal hiring process like a public job posting or structured interview. It came through friends and networking, which is quite common here.

Our main concerns are:

  • Could this cause problems with immigration, since dependents are normally limited to 28 hours per week?
  • Would there be tax issues if his income is similar to a full-time salary but the contract says part-time?
  • Is this arrangement something people commonly do, or is it too risky legally?

I’d really appreciate hearing from anyone familiar with working in Japan on a dependent visa or who has dealt with similar situations.

by Worldly-Throat3089