Japan's Residence Tax Arrives a Year Late, and That Matters

Japan levies two income taxes on employees. National income tax, shotokuzei, is withheld monthly and reconciled through the year end adjustment. Local inhabitant tax, juminzei, is charged at a flat ten percent split between prefecture and municipality, plus a small per capita levy.

The difference between them is timing. Inhabitant tax for a given calendar year is assessed on that year's income and collected between June of the following year and May of the year after that.

What the lag produces

Your first year in Japan carries no inhabitant tax at all, because there was no Japanese income in the preceding year. Net pay in year one is therefore higher than it will be afterwards.
From June of your second year, inhabitant tax on year one income begins to be deducted, and net pay falls with no change in salary.
A year of high income is followed by a year of high inhabitant tax, regardless of what happened to income in the meantime.
Leaving Japan does not cancel the liability for income already earned, and the outstanding amount becomes payable.

The second point is the one that surprises almost every new arrival. A salary that felt comfortable in the first year becomes noticeably tighter from the June of the second, and the cause is not a pay cut.

Two collection methods

Method	How it works	Who uses it
Tokubetsu choshu	Deducted by the employer in twelve monthly instalments from June to May	Most employees
Futsu choshu	Billed directly to the individual in four instalments	The self-employed, and employees whose employer does not operate special collection

Special collection through payroll is the norm and it spreads the cost evenly. Direct collection concentrates it into four payments, which is harder to budget for and is the method that applies after leaving employment.

Leaving Japan

This is the situation that requires action. Someone departing partway through a year owes inhabitant tax on the previous year's income and, in due course, on the current year's income up to departure.

Appoint a tax agent, a nozei kanrinin, resident in Japan who receives the assessment and handles payment on your behalf. This is the standard approach and it requires a form filed before departure.
Or pay in a lump sum before leaving. The employer can deduct the remaining balance from the final salary payment, which is simpler if the amount is known.
File a final national tax return if required, before departure or through the agent.
Do not simply leave. The obligation persists, and it complicates any future return to Japan.

What reduces it

Inhabitant tax is calculated on a base similar to national income tax but with slightly different deductions, notably a smaller basic deduction. Social insurance premiums are fully deductible from both, which is why the shakai hoken contribution reduces the tax bill as well as taking money from the payslip. That contribution is covered in shakai hoken explained.

The furusato nozei scheme allows a portion of inhabitant tax to be redirected to a chosen municipality in exchange for a return gift, at a net cost of a small fixed amount. It is one of the few genuinely popular tax mechanisms anywhere and is covered in furusato nozei.

Planning around the lag

The practical advice for anyone arriving in Japan is to treat first year net pay as temporarily inflated and to set aside roughly ten percent of income against the bill that starts in June of the second year. For anyone leaving, the advice is to establish the outstanding balance early, because it is easier to settle while still employed.

The Japanese calculator includes both national and inhabitant tax, so the figure shown reflects the steady state rather than the first year. Use the Japan Salary calculator.