[makx]

> You can't start a side business on a regular work visa.

This is incorrect.

A friend of mine started a businesses on a work visa and I myself have even started a business on a student visa [1]. No legal problems. I just recently switched from "Student" to "Manager" visa, and immigration had no problems with the fact that the business was already running for over a year before I applied for my residence status to be changed.

[1] http://marui-plugin.blogspot.jp/2016/11/starting-company-as-...

[laurieg]

Sorry if my statement was inaccurate. The legal advice I have received states that if I were to start a company I would need to change residence types or would be unable to renew my current visa.

So how does your friend renew his visa? Does he renew as a standard work visa and declare his company at the same time?

[makx]

As long as you have your current position (employment in my friends case or university enrollment in my case) you can extend the visa on those grounds, basically making you business a "side-business". After you quit your job or leave university, your visa stays valid until the end of the term. When the visa expires, you will have to apply for a Business Manager (経営者) visa, because you are not an employee (授業員) at your company, but an executive (役員).