Article 20Scope of the Taxable Period Including the Day on Which a Business Commenced, etc.
第二十条（事業を開始した日の属する課税期間等の範囲）
The taxable periods specified by Cabinet Order as provided for in Article 9, paragraph (4) of the Act are the following taxable periods:
法第九条第四項に規定する政令で定める課税期間は、次に掲げる課税期間とする。
the taxable period that includes the day on which a business operator commenced a business pertaining to taxable transfers, etc. of assets in Japan;
事業者が国内において課税資産の譲渡等に係る事業を開始した日の属する課税期間
where an individual business operator has succeeded, by inheritance, to the business of a decedent who was subject to the application of Article 9, paragraph (4) of the Act, the taxable period that includes the day of that inheritance;
個人事業者が相続により法第九条第四項の規定の適用を受けていた被相続人の事業を承継した場合における当該相続があつた日の属する課税期間
where a corporation has succeeded, by a merger (excluding the case where a corporation is established by the merger), to the business of a merged corporation that was subject to the application of Article 9, paragraph (4) of the Act, the taxable period that includes the day of that merger;
法人が合併（合併により法人を設立する場合を除く。）により法第九条第四項の規定の適用を受けていた被合併法人の事業を承継した場合における当該合併があつた日の属する課税期間
where a corporation has succeeded, by an absorption-type company split, to the business of a splitting corporation that was subject to the application of Article 9, paragraph (4) of the Act, the taxable period that includes the day of that absorption-type company split.
法人が吸収分割により法第九条第四項の規定の適用を受けていた分割法人の事業を承継した場合における当該吸収分割があつた日の属する課税期間
Read this with the articles around it