Ways of Working Independently
If you don't work full time for just one employer but work for a few different employers or have signed contract with several clients as a freelancer, it is still possible to get a work visa. This procedure is often referred to as Self Sponsorship.
There is no such thing as "self sponsor visa" however, so you will be applying for an ordinary working visa such as "Engineer / Specialist in Humanities and International Services".
You will need to prove that you have already signed stable contracts with different employers/clients in Japan that would generate enough income to support yourself (approximately 200,000 yen/month at the minimum).
This doesn't work when you only have contracts with overseas companies that don't have any office in Japan, although you could work for foreign companies on top if you have already secured sufficient income with Japanese companies.
It is also required to get a certain number of documents such as the registry certificate, financial statements, withholding tax report from one of the main employer / client in Japan and have them stamp their official seal on the application form as a main "visa sponsor".
If you are planning to start a new business but don't have fixed clients yet, you might like to consider applying for the "Investor/Business Manager" visa.
Private lessons don't count unless they are organized continuously by a Japanese company.
Certified as Immigration Lawyers by the Japan Immigration Office, we can help you with obtaining an appropriate visa and with other immigration procedures.