•IRS Publication 901 U.S. Tax Treaties ((( PDF file ))) --- Sept. 2016
Income, other than a pension, paid by Japan, its political subdivisions, or local authorities to an individual for services performed for the paying governmental body is exempt from U.S. income tax. However, the exemption does not apply if the services are performed in the United States by a resident of the United States who either:
● Is a U.S. citizen, or
● Did not become a U.S. resident only to perform the services.
Pensions paid by, or out of funds to which contributions are made by, Japan, its political subdivisions, or local authorities for services performed for Japan are exempt from U.S. income tax unless the recipient is a resident and citizen of the United States.
These exemptions do not apply to income or pensions for services performed in connection with a business carried on by Japan, its political subdivisions, or local authorities.