Welcome to Just Answer. My name is ***** ***** it will be my pleasure to assist you with your tax question today.
Alimony paid by your U.S. citizen client to his ex-wife in Japan is deductible
on his tax return. You cannot efile the tax return if the there is no SSN or ITIN.
tax is imposed on U.S.-source alimony at a flat 30% of the gross amount paid to the nonresident
recipient. This is the default U.S. income tax treatment that a nonresident alien
recipient of alimony from a U.S. spouse or ex-spouse should expect.
This result, however, can be altered by claiming benefits
under a relevant income tax treaty.
The following link contains excellent information regarding alimony payments to non-resident aliens:
Please let me know if you require further information or clarification. In the meantime, I will check the U.S./Japan tax treaty to determine the tax rate
(if any) for the alimony paid to the ex-wife.
Thank you and best regards,