This Act comes into effect as of January 1, 1948.

In these Supplementary Provisions, "New Act" means the Family Register Act as amended by this Act; "Old Act" means the Family Register Act previously in force; "New Civil Code" means the Act Partially Amending the Civil Code that comes into effect on the same day as this Act; "Old Civil Code" means the Civil Code previously in force; and "Emergency Measures Act" means Act No. 74 of 1947.

①A family register under the provisions of the Old Act is deemed to be a family register under the provisions of the New Act; provided, however, that when ten years have elapsed after the New Act comes into effect, family registers under the provisions of the Old Act must be remade under the New Act, as provided for by Ministry of Justice Order.

②A registered domicile designated under the Old Act is deemed to have been designated under the New Act.

In cases where the Old Civil Code applies, the Old Act continues to apply even after the New Act comes into effect.

The New Act also applies to cases in which an entry is made in a family register or a new family register is created based on a notification or any other grounds arising before the New Act comes into effect.

①When a new family register is created for a person in a family register referred to in Article 3, paragraph (1) of the Supplementary Provisions, any child of that person who is in the family register referred to in that paragraph and who continues to have the same surname as that person joins the new family register; provided, however, that this does not apply if that child has a spouse or has a child in the same family register as them.

②In the case referred to in the preceding paragraph, if the new registered domicile is designated within the same municipality as the locality of the previous registered domicile, the provisions of Article 30, paragraph (2) do not apply.

The provisions of Article 19, paragraph (1) and Article 99 apply mutatis mutandis to cases in which a person reverts to their previous surname pursuant to the provisions of Article 12 of the Supplementary Provisions of the New Civil Code.

A person in a family register referred to in Article 3, paragraph (1) of the Supplementary Provisions who has a spouse may not separate from their family register unless they do so jointly with their spouse.

①If, after the Emergency Measures Act comes into effect and before the New Act comes into effect, an agreement determining the person with parental authority has been reached pursuant to the provisions of the first sentence of Article 6, paragraph (2) of the Emergency Measures Act, the person with parental authority must submit a notification to that effect within ten days from the day on which the New Act comes into effect, together with a document proving the agreement. In this case, the provisions of the proviso to Article 38, paragraph (1) and Article 39 apply mutatis mutandis.

②If, after the Emergency Measures Act comes into effect and before the New Act comes into effect, a judicial decision prescribed in the second sentence of Article 6, paragraph (2) of the Emergency Measures Act or in paragraph (3) of that Article has become final and binding, the person with parental authority must submit a notification to that effect within ten days from the day on which the New Act comes into effect, together with a transcript of the judicial decision. The date that the judicial decision became final and binding must be entered in the written notification.

①The provisions of Article 78 apply mutatis mutandis to a person who seeks to determine the person with parental authority by agreement pursuant to the provisions of the proviso to Article 14, paragraph (1) of the Supplementary Provisions of the New Civil Code.

②The provisions of Article 63 apply mutatis mutandis to the person with parental authority in cases where a judicial decision prescribed in Article 14, paragraph (2) or (3) of the Supplementary Provisions of the New Civil Code has become final and binding.

A person who actually holds the position of supervisor of guardian at the time the New Act comes into effect must submit the notification prescribed in Article 81 or Article 82 as applied mutatis mutandis pursuant to Article 85 within ten days from the day on which the New Act comes into effect.

When a notification of the transfer of registered domicile is made with regard to a family register referred to in Article 3, paragraph (1) of the Supplementary Provisions, a family register is created based on the previous family register, notwithstanding the provisions of the New Act.

②With regard to the entrustment of family register notifications made before this Act comes into effect, Act No. 4 of 1940 remains in force. In this case, the confirmation referred to in Article 1, paragraph (1) of that Act is made by the family court.

③The provisions of Article 122 apply mutatis mutandis to the confirmation referred to in the preceding paragraph.

With regard to the application of the provisions on civil fines to acts committed before this Act comes into effect, the provisions then in force continue to govern.

With regard to civil fine cases actually pending before a court at the time this Act comes into effect, the provisions then in force continue to govern.