Working options while studying in Japan full-time

I'm planning on moving to Tokyo in 2027 and am currently in the process of seeing whether i can get a transfer with my current company as we have an office in Shinagawa.

I'm a 35 year old consultant for a large tech company however my main area of expertise lies in a category of marketing software which i've been using and consulting on for the past 12 years.

I began learning Japanese last year and have my N5, however my Japanese is a long way off although I am continuing to study hard alongside full time work.

The chances of me getting a transfer with my company are slim, so if/when that falls through, I'm wanting to enter Japan on a student visa to focus on learning Japanese full time, so at some point in the future i could consider getting back into my industry over there.

I realise there are restrictions in terms of part time work on a student visa (<28 hours/week) however I am trying to think through what work I could do part time. In particular, I'm considering freelance consulting, the same work I'm doing now, just on my own as this can generate a somewhat decent income.

However, freelance consulting seems to be a real grey area which i can't seem to get any concrete response on. Some people i've spoken to have said this would not be allowed as your part time work needs to be with a Japanese company, others have said it could work with special permission. I've emailed a few Japanese agencies/immigration and also spoken to a few language schools but am still searching for an answer.

My question would be have any of you who have moved to Japan on a student visa, done freelance consulting and if so, how did you navigate this?

If not, I'd love to hear any other recommendations or experiences others have had when moving to Japan on a student visa in terms of what they did to generate a form of income.

by JTE0303