Schemes: health insurance (Kyōkai Kenpo, Tokyo rate seeded), nursing care (ages 40–64), employees' pension (9.15% each, ¥650,000 cap), employment insurance (0.55% / 0.90%), income-tax withholding (Kō, the official electronic-computation formula from the MOF notice — set dependents on the registration, counting the withholding-eligible spouse plus dependents), and resident tax (per-employee amount from the June municipal notice — set a fixed amount on each registration).
What each employee provides
- Date of birth (nursing-care band), dependents declaration (Kō), and the municipal resident-tax notice amount each June.
Worked example — ¥300,000, age 44, 2 dependents
Health ¥14,865 · nursing ¥2,385 · pension ¥27,450 · EI ¥1,650 (employer ¥2,700) → post-insurance wage ¥253,650 → withholding ¥3,020 by the Reiwa 8 formula (income deduction ¥82,762, dependents ¥63,334, basic ¥48,334 → ¥59,220 × 5.105%, rounded to ¥10). The notice's own examples — ¥175,000 with 2 dependents → ¥210; ¥446,000 with 8 → ¥940; ¥775,200 with 3 → ¥59,470 — are pinned in the test suite.
Limitations
Health/pension are seeded as percents with ceilings — the statutory standard-remuneration grade tables match these at band midpoints; enter the grade rows for exact-yen agreement. Withholding follows the official electronic-computation special (both the 2021–2025 and the 2026 notices are seeded as effective-dated versions); amounts can differ from the printed table by design and reconcile at year-end adjustment. Prefecture health rates other than Tokyo are tenant-added versions; the bonus calculation path and year-end adjustment (nenmatsu chōsei) are later phases.