Japan: proof of nationality and consequence of annulment of paternity

On 10 December 2022, the Parliament of Japan (referred to as the Diet) passed a Bill to amend the Civil Code and the Nationality Act. These amendments concern proof of nationality and the loss of nationality due to annulment of parentage.

Proof of nationality 

The first objective of the amendment is to reduce cases of mukoseki. This term refers to Japanese persons not registered on family registers (Koseki) which serve as proof of Japanese nationality. There are 793 persons known as Mukoseki to the authorities as of November 2022, but civil society groups estimate there are more than 10,000 in total, in some cases affecting more than two generations over several decades. One of the main causes of mukoseki cases is the Japanese Civil Code’s rule that presumes that children born within 300 days of a divorce descend from the former husband, which has prevented victims of domestic violence from registering their children so as to avoid contact with their former husbands. The recent amendments, among other things, provide an exemption to this presumption for mothers who remarry before the child’s birth (meaning that the new husband will be presumed to be their father). Civil society organizations pointed out that the amendments do not address the situation of those children whose mothers do not remarry after divorce, and that more fundamental amendments are needed to end the mukoseki problem.

Loss of nationality due to annulment of paternity

Along with the amendments to the Civil Code, it has been proposed to amend the Japanese Nationality Act to enable retroactive and automatic loss of nationality when no biological parentage exists between a child born out of wedlock and the Japanese father who acknowledges paternity of the child, even if this results in statelessness and regardless of the lapse of time.  Among other organizations such as Forum for Refugees Japan (FRJ)  and a group of lawyers, UNHCR has issued comments recommending the reformulation of the Bill in order to avoid statelessness. It has recommended not to annul nationality acquisition when it results in statelessness, and proposed a limitation period beyond which acquired nationality cannot be withdrawn.

While the amendment to the Nationality Act has been passed without modifications, Additional Resolutions have been adopted by the Diet, which call for “(…) flexible and humanitarian responses in naturalization and grant of residency status for the speedy stabilization of the legal status of children whose Japanese nationality is denied, paying due attention to prevention and reduction of statelessness, and the fact that the persons concerned have previously lived as Japanese nationals.” The Resolutions also call for a review of the challenges arising from the retroactive loss of Japanese nationality after the Bill comes into force. Preceding such resolutions, extensive parliamentary debate was held, where references were made to international legal standards governing statelessness. In so doing, the importance of addressing statelessness, including in inter-agency policies, was acknowledged by the Government and parliamentarians.

The text of the amendment can be found here (in Japanese).

For more information on citizenship laws in Japan, see the GLOBALCIT Country Report on Japan.

For more information on the global regulation of loss of nationality due to annulment of parentage, see the GLOBALCIT Citizenship Law Dataset – Modes of Loss of Citizenship (mode L13a).