# 所得税法 / Income Tax Act — 第一条 (Supplementary Provisions, Article 1)

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- Law: 所得税法 (Income Tax Act), 昭和四十年法律第三十三号
- English title "Income Tax Act": Ministry of Justice translation
- Kind: Act — the distinction between 法律 (Act), 政令 (Cabinet Order), 省令 (Ministerial Order) and 条例 (local ordinance) decides who may issue it and what it may say.
- Provision: 第一条 (Supplementary Provisions, Article 1)（施行期日） — address `suppl-5081-12/art-1`
- Text in force since: 2026-10-01
- URL (the page that opens at this provision): https://japanlaw.org/en/income-tax-act/suppl-5081-12/art-1
- e-Gov law ID: 340AC0000000033 — never renamed. A permanent link, `/l/{lawId}/{address}` on this site, redirects to the page.
- Every provision below carries its address and its URL on the line under it.
- Japanese text: e-Gov 法令検索, Digital Agency (デジタル庁). English: as marked on each line below.

Only the Japanese as published by the government has legal effect; the text
below is a copy of it. Every English rendering below is a translation and
says which kind: the Ministry of Justice's translation, or this
site's machine translation, whose model and date the Sources list names.
They are never merged and never substituted for one another.

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### 第一条（施行期日） — Effective Date
<sup>caption: machine translation, not official</sup>
<sup>suppl-5081-12/art-1 · https://japanlaw.org/en/income-tax-act/suppl-5081-12/art-1</sup>

**第一項**  この法律は、令和八年四月一日から施行する。ただし、次の各号に掲げる規定は、当該各号に定める日から施行する。
<sup>suppl-5081-12/art-1/par-1 · https://japanlaw.org/en/income-tax-act/suppl-5081-12/art-1/par-1</sup>
This Act comes into effect on April 1, 2026; provided, however, that the provisions set forth in the following items come into effect on the dates specified respectively in those items:
<sup>machine translation, not official</sup>

  **一から三まで**  略
  <sup>suppl-5081-12/art-1/par-1/item-1-to-3 · https://japanlaw.org/en/income-tax-act/suppl-5081-12/art-1/par-1/item-1-to-3</sup>
  Omitted
  <sup>machine translation, not official</sup>

  **四**  次に掲げる規定　令和八年十二月一日
  <sup>suppl-5081-12/art-1/par-1/item-4 · https://japanlaw.org/en/income-tax-act/suppl-5081-12/art-1/par-1/item-4</sup>
  the following provisions: December 1, 2026;
  <sup>machine translation, not official</sup>

    **イ**  第一条中所得税法第二条第一項第三十二号の改正規定（同号ロに係る部分を除く。）、同項第三十三号及び第三十四号の改正規定、同法第二十八条第三項の改正規定、同法第八十六条第一項第一号の改正規定並びに同法別表第二から別表第五までの改正規定（別表第五に係る部分に限る。）並びに次条並びに附則第三条、第九条、第十一条第二項から第四項まで、第十二条及び第十三条第二項の規定
    <sup>suppl-5081-12/art-1/par-1/item-4/sub-1 · https://japanlaw.org/en/income-tax-act/suppl-5081-12/art-1/par-1/item-4/sub-1</sup>
    the provisions in Article 1 amending Article 2, paragraph (1), item (xxxii) of the Income Tax Act (excluding the part concerning (b) of that item), amending items (xxxiii) and (xxxiv) of that paragraph, amending Article 28, paragraph (3) of that Act, amending Article 86, paragraph (1), item (i) of that Act, and amending Appended Tables II through V of that Act (limited to the part concerning Appended Table V), and the provisions of the following Article and of Article 3, Article 9, Article 11, paragraphs (2) through (4), Article 12, and Article 13, paragraph (2) of the Supplementary Provisions;
    <sup>machine translation, not official</sup>

  **五**  次に掲げる規定　令和九年一月一日
  <sup>suppl-5081-12/art-1/par-1/item-5 · https://japanlaw.org/en/income-tax-act/suppl-5081-12/art-1/par-1/item-5</sup>
  the following provisions: January 1, 2027;
  <sup>machine translation, not official</sup>

    **イ**  第一条中所得税法第三十五条に一項を加える改正規定、同法第八十一条第一項の改正規定、同法第百二十条の改正規定、同法第二百三条の三の改正規定及び同法別表第二から別表第五までの改正規定（別表第五に係る部分を除く。）並びに附則第五条、第八条、第十条、第十一条第一項及び第十三条第一項の規定
    <sup>suppl-5081-12/art-1/par-1/item-5/sub-1 · https://japanlaw.org/en/income-tax-act/suppl-5081-12/art-1/par-1/item-5/sub-1</sup>
    the provisions in Article 1 adding one paragraph to Article 35 of the Income Tax Act, amending Article 81, paragraph (1) of that Act, amending Article 120 of that Act, amending Article 203-3 of that Act, and amending Appended Tables II through V of that Act (excluding the part concerning Appended Table V), and the provisions of Article 5, Article 8, Article 10, Article 11, paragraph (1), and Article 13, paragraph (1) of the Supplementary Provisions;
    <sup>machine translation, not official</sup>

  **六から九まで**  略
  <sup>suppl-5081-12/art-1/par-1/item-6-to-9 · https://japanlaw.org/en/income-tax-act/suppl-5081-12/art-1/par-1/item-6-to-9</sup>
  Omitted
  <sup>machine translation, not official</sup>

  **十**  次に掲げる規定　次号に掲げる規定の施行の日の属する年の翌年の一月一日
  <sup>suppl-5081-12/art-1/par-1/item-10 · https://japanlaw.org/en/income-tax-act/suppl-5081-12/art-1/par-1/item-10</sup>
  the following provisions: January 1 of the year following the year that includes the date on which the provisions set forth in the following item come into effect;
  <sup>machine translation, not official</sup>

    **イ**  第一条中所得税法第二条第一項第十六号の改正規定、同項第二十五号の改正規定、同法第二十二条第二項第一号の改正規定、同法第三十三条の改正規定、同法第四十八条の二第一項の改正規定（「（資金決済に関する法律（平成二十一年法律第五十九号）第二条第十四項（定義）に規定する暗号資産をいう。以下この条において同じ。）」を削る部分を除く。）及び同法第六十九条第二項の改正規定並びに附則第四条、第六条第一項及び第七条の規定
    <sup>suppl-5081-12/art-1/par-1/item-10/sub-1 · https://japanlaw.org/en/income-tax-act/suppl-5081-12/art-1/par-1/item-10/sub-1</sup>
    the provisions in Article 1 amending Article 2, paragraph (1), item (xvi) of the Income Tax Act, amending item (xxv) of that paragraph, amending Article 22, paragraph (2), item (i) of that Act, amending Article 33 of that Act, amending Article 48-2, paragraph (1) of that Act (excluding the part deleting "(meaning cryptoassets as prescribed in Article 2, paragraph (14) (Definitions) of the Payment Services Act (Act No. 59 of 2009); the same applies hereinafter in this Article)"), and amending Article 69, paragraph (2) of that Act, and the provisions of Article 4, Article 6, paragraph (1), and Article 7 of the Supplementary Provisions;
    <sup>machine translation, not official</sup>

  **十一**  第一条中所得税法第四十八条の二第一項の改正規定（「（資金決済に関する法律（平成二十一年法律第五十九号）第二条第十四項（定義）に規定する暗号資産をいう。以下この条において同じ。）」を削る部分に限る。）並びに同法第二百二十四条の三第一項、第三項及び第四項の改正規定並びに附則第六条第二項の規定　金融商品取引法及び資金決済に関する法律の一部を改正する法律（令和八年法律第六十四号）の施行の日
  <sup>suppl-5081-12/art-1/par-1/item-11 · https://japanlaw.org/en/income-tax-act/suppl-5081-12/art-1/par-1/item-11</sup>
  the provisions in Article 1 amending Article 48-2, paragraph (1) of the Income Tax Act (limited to the part deleting "(meaning cryptoassets as prescribed in Article 2, paragraph (14) (Definitions) of the Payment Services Act (Act No. 59 of 2009); the same applies hereinafter in this Article)") and amending Article 224-3, paragraphs (1), (3), and (4) of that Act, and the provisions of Article 6, paragraph (2) of the Supplementary Provisions: the date on which the Act Partially Amending the Financial Instruments and Exchange Act and the Payment Services Act (Act No. 64 of 2026) comes into effect.
  <sup>machine translation, not official</sup>

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## Cites
- suppl-5081-12/art-1/par-1/item-10: 次号 → 所得税法 附則第一条第一項第十一号 (Supplementary Provisions, Article 1, paragraph (1), item (xi)), suppl-5081-12/art-1/par-1/item-11 — https://japanlaw.org/en/income-tax-act/suppl-5081-12/art-1/par-1/item-11
- suppl-5081-12/art-1/par-1/item-10/sub-1: 資金決済に関する法律（平成二十一年法律第五十九号）第二条第十四項 → 資金決済に関する法律 第二条第十四項 (Article 2, paragraph (14)), art-2/par-14 — https://japanlaw.org/en/payment-services-act/art-2/par-14 (e-Gov law ID 421AC0000000059)
- suppl-5081-12/art-1/par-1/item-11: 資金決済に関する法律（平成二十一年法律第五十九号）第二条第十四項 → 資金決済に関する法律 第二条第十四項 (Article 2, paragraph (14)), art-2/par-14 — https://japanlaw.org/en/payment-services-act/art-2/par-14 (e-Gov law ID 421AC0000000059)

## Cited by

2 provisions cite this one. No official source publishes this direction.

- 所得税法 附則第一条第一項第十号（施行期日） — https://japanlaw.org/en/income-tax-act/suppl-5081-12/art-1/par-1/item-10
- 所得税法 附則第九十九条第一項（罰則に関する経過措置） — https://japanlaw.org/en/income-tax-act/suppl-5081-12/art-99/par-1

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## Sources

- e-Gov 法令検索, Digital Agency (デジタル庁) — 所得税法 — the text in force from 2026-10-01 (https://laws.e-gov.go.jp/law/340AC0000000033/20261001_507AC0000000070), retrieved 2026-10-05
- Japanese Law Translation Database System, Ministry of Justice (法務省) — Income Tax Act — Ministry of Justice translation (https://www.japaneselawtranslation.go.jp/en/laws/view/3120/tb), retrieved 2026-09-18
- claude-opus-5[1m] — Machine translation, batch income-tax-act-20260918T174921-140, translated 2026-10-12
- claude-opus-5[1m] — Machine translation, batch income-tax-act-20260918T180319-138, translated 2026-10-12
- This site's parser, version 225 — 所得税法 — structure, counts, cross-references and defined terms, computed 2026-10-05