I go back to the first response I wrote:
You listed three sources of income, and I addressed each sparately:
Under the Japan US Tax Treaty:
https://www.irs.gov/businesses/internat ... -documents
https://www.mof.go.jp/tax_policy/summar ... _ST_en.pdf
1. US Social Security - taxable in Japan
"ARTICLE 17
1. Subject to the provisions of paragraph 2 of Article 18, pensions and other similar remuneration, including social security payments, beneficially owned by a resident of a Contracting State shall be taxable only in that Contracting State."
Paragraph 2 of Article 18 specifically excludes Government Service Pension from the provisions of Article 17, and pushes it to Article 18. See below.
"pensions and other similar remuneration, including social security payments, beneficially owned by a Resident of a Contracting State (Japan) shall be taxable only in that Contracting State (Japan)." -
You are Resident in Japan, so your social security payments are taxable in Japan.
Further, US Social Security qualifies for the Public Pension Tax Deduction, which gives you about an additional Y1+M of Tax Deduction on top of other allowances and deductions.
Best reference is here - Page 8 (page 12 of the PDF)
Calculating the Public Pension Plan Deduction (Calculation Table)
https://www.tax.metro.tokyo.lg.jp/book/ ... k2023e.pdf
Also here - Bottom of Page 22 (under 65) and top of Page 23 (over 65)
https://www.nta.go.jp/taxes/shiraberu/s ... df/050.pdf
So, You get your Base Deduction of Y480,000, maybe Spouse Deduction Y380,000 if your spouse is dependent and not working, or only working part-time and earning less than Y480,000 per year, Household National Health Care Premium Deduction, Healthcare Costs over Y100,000 Deduction, (any dependent children or parents?), any other Insurance Premiums (health, life, earthquake, etc.), any other Deductions or Allowances PLUS the Y1+M Public Pension Deduction.
Your Social Security Pension should be completely Tax Free in the US, so the only tax you will pay is in Japan after all these allowances and deductions...
2. Teacher Pension from California -
If this is a Government Service Pension for service to the California State Government, paid by the State or School District - Only Taxable in the US, if you are not a Japanese Citizen...
"ARTICLE 18
...
2. (a) Any pension and other similar remuneration paid by, or out of funds to which contributions are made by, a Contracting State or a political subdivision or local authority thereof to an individual in respect of services rendered to that Contracting State or a political subdivision or local authority thereof, other than payments made by the United States under provisions of the social security or similar legislation, shall be taxable only in that Contracting State.
(b) However, such pension and other similar remuneration shall be taxable only in the other Contracting State if the individual is a resident of, and a national of, that other Contracting State."
"other than payments made by the United States under provisions of the social security or similar legislation" - pushes your Social Security Pension back to Article 17, discussed above.
"Any pension...paid by...by a Contracting State (US) or a political subdivision or local authority...in respect of services rendered to that Contracting State (US) or a political subdivision or local authority thereof... shall be taxable only in that Contracting State (US).
unless
"...such pension...shall be taxable only in the other Contracting State (Japan) if the individual is a Resident of, AND a National of that other Contracting State (Japan)."
I assume you are not a Japanese National, so Paragraph 2(a) refers. - Not taxable in Japan.
3. Bank interest - taxable in Japan
"ARTICLE 11
1. Interest arising in a Contracting State and beneficially owned by a resident of the other Contracting State may be taxed only in that other Contracting State."
Interest arising in a Contracting State (US) and beneficially owned by a resident of the other Contracting State (Japan) may be taxed only in that other Contracting State (Japan)."
However, if you are still Non-Permanent Resident for Tax Purposes, having been in Japan for less than 5 years in the last 10 years, only funds remitted to Japan from the Social Security and Bank Interest Income are taxable in Japan.
Social Security and Bank Interest Income would be considered to have been the funds remitted to Japan, and taxable, before the Teacher's Pension, non-taxable.