Everyone in Japan, 20 to 60 years of age, must also pay into the National Pension Program.
Please refer to the site: Japan Pension Service.
OIST has a contract with a professional tax accountant who speaks fluent English and also has a mastery of taxation in Japan and tax treaties. If you have any question related to tax issues, please contact at email@example.com. HR will refer you to or seek advice from a tax accountant, if needed.