logigrain.net

Japan new NISA limits: how much can still be bought this year and next year under the annual limits (つみたて 1.2M / 成長 2.4M yen) and the 18M-yen lifetime book-value limit (成長 up to 12M). Selling frees the book value (cost), not the sale price, from the next year. Returns the rule basis, assumptions, what would change the answer and a quotable sentence; asks for book values instead of guessing. Rules checked against the FSA NISA site.

Japan mortgage tax deduction (住宅ローン控除) for move-ins 2026-2030 (FY2026 reform): borrowing limit and 13/10-year period by home type, performance class, special household and floor area; yearly deduction or a full-period projection from a loan, split between income and resident tax. Refuses older move-ins; asks for missing facts. Checked against National Tax Agency tax answers and an independent implementation.

Moon phase from a true ephemeris: age, illumination, phase name (Japanese/English), next full and new moon date and time (within about 2 minutes), timezone aware.

When to start the Japanese public pension: break-even age of early claim or deferral versus a baseline, probability of living to that age from the official Japanese life table (令和7年簡易生命表, by sex), and expected lifetime total for each start age 60-75. Returns the rule year used, assumptions, what would change the answer, and a quotable sentence. Totals cross-checked by an independent implementation.