As one of very useful measuring for travel visa (90 days short stay) who have difficulty to return to own home country or other country because the travel restriction from COVID-19
You can extend your visa at the immigration office to get another 90 days temporary visa. Moreover , if one gets a serious financial problem during your stay in Japan, you should get a part-time work permit up to 28 hours per week. For this part-time work permit, you need to apply to the immigration office.
You need to cover following conditions
1)your current visa status does not allow to get work
2)You can’t return to your own country or other country
3)You got a serious financial problem during your stay in Japan and no one can support you.
Here is the detail
What you have to submit?
The application for the part-time work permit
An evidence which proves a difficulty of your travel from Japan
An explanation of your personal status and reason to apply (the form)