第二十条（国税通則法の一部改正に伴う経過措置）
Supplementary Provisions, Article 20Transitional Measures Accompanying the Partial Amendment of the Act on General Rules for National Taxes
第九条の規定による改正後の国税通則法（以下この条において「新国税通則法」という。）第十九条第四項及び第二十三条第三項の規定は、令和四年十二月三十一日以後に課税期間が終了する国税（課税期間のない国税については、同日後にその納税義務が成立する当該国税）に係る新国税通則法第十九条第三項に規定する修正申告書又は新国税通則法第二十三条第三項に規定する更正請求書について適用し、同日前に課税期間が終了した国税（課税期間のない国税については、同日以前にその納税義務が成立した当該国税）に係る第九条の規定による改正前の国税通則法（以下この項において「旧国税通則法」という。）第十九条第三項に規定する修正申告書又は旧国税通則法第二十三条第三項に規定する更正請求書については、なお従前の例による。
Article 19, paragraph (4) and Article 23, paragraph (3) of the Act on General Rules for National Taxes as amended by Article 9 (hereinafter referred to as "the new Act on General Rules for National Taxes" in this Article) apply to an amended return prescribed in Article 19, paragraph (3) of the new Act on General Rules for National Taxes or a written request for reassessment prescribed in Article 23, paragraph (3) of the new Act on General Rules for National Taxes with respect to a national tax whose taxable period ends on or after December 31, 2022 (for a national tax without a taxable period, such national tax whose tax liability becomes established after that date), and the provisions then in force continue to govern an amended return prescribed in Article 19, paragraph (3) of the Act on General Rules for National Taxes prior to the amendment by Article 9 (hereinafter referred to as "the former Act on General Rules for National Taxes" in this paragraph) or a written request for reassessment prescribed in Article 23, paragraph (3) of the former Act on General Rules for National Taxes with respect to a national tax whose taxable period ended before that date (for a national tax without a taxable period, such national tax whose tax liability became established on or before that date).
新国税通則法第六十五条第四項及び第六十六条第四項の規定は、令和六年一月一日以後に法定申告期限（国税に関する法律の規定により当該法定申告期限とみなされる期限を含み、国税通則法第六十一条第一項第二号に規定する還付請求申告書については、当該申告書を提出した日とする。）が到来する国税について適用する。
Article 65, paragraph (4) and Article 66, paragraph (4) of the new Act on General Rules for National Taxes apply to a national tax for which the statutory tax return due date (including a due date deemed to be the statutory tax return due date under the provisions of the national tax laws, and, for a return of refund claim prescribed in Article 61, paragraph (1), item (ii) of the Act on General Rules for National Taxes, meaning the date on which the return was filed) arrives on or after January 1, 2024.