Every tool here is a single HTML page that runs entirely in your browser
— no accounts, no backend, and nothing you enter leaves your device. The
one exception is opt-in: AI-assisted features call Anthropic directly
with your own API key, only when you use them. The flagship, Taigan
Bridge, is meant to be downloaded and opened locally; the copy hosted
here is a guided demo loaded with sample data.
Financial, tax, estate, and health planning for Americans on the opposite shore.
Sixteen bilingual EN/JP modules — net worth, FBAR, tax coordination, retirement projections, estate, property, family, healthcare, and more — behind a short branching onboarding so the dashboard only shows what applies to your household. Local-only: your data lives in your browser, no accounts, no telemetry. The copy hosted here is a guided demo pre-loaded with a sample household; download the single HTML file for real use.
Work out your accounts’ max values and whether you cross the $10,000 threshold.
Enter your foreign accounts’ peak balances and it converts them at the official US Treasury year-end exchange rate, then tells you whether you must file an FBAR (FinCEN Form 114). Runs entirely in your browser — nothing is saved or sent.
Estimate your hometown-tax limit — with the US Foreign Tax Credit catch built in.
Estimates your furusato nozei donation limit from your income and household using the official method, then shows what it means for a US person: the gift value, the ¥2,000 cost, and the Foreign Tax Credit interaction no Japanese calculator covers. Runs entirely in your browser — no network request, nothing saved.
Estimate your Japanese pension and how it fits with US Social Security.
Estimates your Japanese public pension — flat-rate 国民年金 plus earnings-related 厚生年金 — from your years of coverage, checks the 10-year minimum, and adjusts for when you claim. Shows the US-person picture: totalization, the WEP repeal, and the 脱退一時金 trade-off. Runs entirely in your browser — nothing saved or sent.
Paste or type your Japanese payslip (給与明細) and it explains every recognized line — earnings, deductions, social insurance, taxes — in plain English, with the US-tax angle, plus a clickable annotated sample. Runs entirely in your browser; nothing is uploaded.