The spouse eligible for the Spouse (Special) Deduction for Japanese Income Tax purposes is defined as follows:
(1) Being a spouse of a resident of Japan.
(2) Sharing the taxpayer’s livelihood.
(3) Having a total annual income of 480,000 yen or less (or 1,030,000 yen or less if only salary income).
Regarding (1), it refers to spouses defined under the Japanese Civil Code, so individuals in relationships without statutory registration, even if they live together, do not qualify as spouses for this purpose (Ministry of Finance, Notification No. 18 Section 2-18, Asset Section 3-10, Tax Examination Section 4-114 Amendment).
Therefore, in principle, the marriage must be registered with the city, ward, or town office based on the Family Registration Law, according to the provisions of the Japanese Civil Code.
However, for foreign individuals who cannot comply with the provisions of the Japanese Civil Code, they are considered based on the “Act on the Application of Laws” in Japan. If they have a valid marital relationship according to the foreign laws applicable to them, they will be interpreted as spouses.
Ultimately, for foreign individuals, if they are a lawful spouse, they will be eligible for the spousal deduction.
It should be noted that if one party is Japanese and the marriage is conducted in Japan, it is always necessary to submit a marriage notification based on the Japanese Family Registration Law.