According to https://taxsummaries.pwc.com/japan/individual/deductions
"In the case of a non-dependent spouse, a special spouse exemption (a maximum JPY 380,000 and JPY 330,000 for national income tax purposes and local inhabitant’s tax purposes) can be taken, depending on the spouse’s income, by taxpayers whose income amount does not exceed JPY 10 million."
If both spouses have below JPY 10 million per year (This assumes the couple is living off of savings), I assume it means the spousal exemption would only apply to one and not both spouses?
by BriefExisting3952