Where the regional commissioner of a Regional Taxation Bureau, the district director of a tax office or the director-general of a customs house pays or appropriates a refund, etc., they must multiply the amount to be refunded or appropriated by the rate of 7.3% per annum, and add this amount (hereinafter referred to as the "interest on refund") to the amount to be refunded or appropriated, based on the number of days in the period from the day following the day specified in each of the following items for the category of refund, etc. listed in the relevant item, until the day of the decision to pay the relevant refund or the day on which the relevant refund is appropriated (where appropriation was possible before that date, the day on which it became possible to make the appropriation) (or during the period otherwise specified by other national tax laws):
a refund or any of the following overpayments: the day on which the national tax causing the refund or overpayment was paid (if such day precedes the statutory payment due date of the national tax, the statutory due date):
An overpayment arising from national tax (including any delinquent national tax and interest tax thereon) for which the payable tax amount has been determined by a reassessment or determination under the provisions of Article 25 (Determination) or an assessment and determination (hereinafter referred to as a "reassessment or determination, etc.") (excluding overpayment as set forth in the following item);
An overpayment arising from the national tax (including any delinquent national tax) for which the payable tax amount is determined without any special procedure upon the establishment of the tax liability, and for which notice of tax payment has been given;
An overpayment specified by Cabinet Order as arising from national tax that is similar to the overpayments listed in (a) or (b);
イ又はロに掲げる過納金に類する国税に係る過納金として政令で定めるもの
an overpayment arising from national tax (including any delinquent tax and interest tax thereon) for which the payable tax amount has been reduced due to a reassessment based on a request for reassessment (including a determination of the taxation agency, a decision of the National Tax Tribunal or a judicial decision on an appeal against or action for a disposition made in response to such a request): the day on which three months have elapsed from the day following the day on which the request for reassessment was made, or the day on which one month has elapsed from the day following the day on which the reassessment was carried out, whichever comes earlier (if such day precedes the statutory payment due date of the national tax, the statutory due date); or
an overpayment or other payment by mistake arising from national tax, except for the overpayments listed in the preceding two items:the day on which one month has elapsed from the day following the day specified by Cabinet Order as the day on which such overpayment or payment by mistake occurred.
In the case referred to in the preceding paragraph, if any of the following items applies, the period specified in the relevant item is deducted from the period prescribed in that paragraph:
where a seizure order or seizure disposition under the provisions of the Civil Enforcement Act (Act No. 4 of 1979) has been issued with regard to the claim for the refund, etc.: the period until the day on which seven days have elapsed from the day following the day on which the seizure order or seizure disposition was served;
還付金等の請求権につき民事執行法（昭和五十四年法律第四号）の規定による差押命令又は差押処分が発せられたとき。 その差押命令又は差押処分の送達を受けた日の翌日から七日を経過した日までの期間
where a provisional seizure has been effected against the claim for the refund, etc.: the period during which the provisional seizure is in effect.
還付金等の請求権につき仮差押えがされたとき。 その仮差押えがされている期間
If an overpayment or payment by mistake arises with regard to a national tax paid in two or more installments, the provisions of paragraph (1) apply to that overpayment or payment by mistake by deeming it to consist of the overpayment or payment by mistake of the amounts obtained by going back successively, in the order of the payment dates, from the amount paid last until the amount of the overpayment or payment by mistake is reached.
If a national tax that has been lawfully paid has become overpaid based on the provisions of an Act that changes the amount payable without affecting the lawful payment, the provisions of paragraph (1) apply to that overpayment by deeming it to be the overpayment or payment by mistake listed in item (iii) of that paragraph and deeming the day on which it became overpaid to be the day listed in that item, respectively.
Where a national tax using the self-assessment system has been paid, if a reassessment (excluding a reassessment based on a request for reassessment) has been made of that national tax on the grounds that the economic results arising from a void act included in the facts that formed the basis for the calculation of its tax basis have been lost due to that act being void, that a voidable act included in those facts has been rescinded, or other grounds specified by Cabinet Order as equivalent thereto, the provisions of paragraph (1) apply to the national tax equivalent to the amount overpaid as a result of that reassessment (including accessory tax thereon that has become overpaid as a result of that reassessment) by deeming the day on which one month has elapsed counting from the day following the day on which that reassessment was made to be the day listed in each item of that paragraph.