Q.1 Dual Citizenship After Naturalization

Q.1 Can I maintain dual citizenship with my home country after naturalizing?

A.1 No, you cannot. A procedure to renounce your home country’s nationality is required.

① Japan Adopts the “Single Nationality” System

Japan’s naturalization system generally adopts the “single nationality” principle. Therefore, when a foreign national naturalizes in Japan, they are required to renounce their home country’s nationality.

In practice, after applying for naturalization, the Legal Affairs Bureau confirms the foreign national’s intention to renounce their home country’s nationality after naturalization. Furthermore, there are cases where the foreign national’s home country’s laws do not automatically cause the loss of nationality upon naturalization to Japan. In such instances, since the Japanese government maintains the position that it does not recognize dual nationality for Japanese citizens, the administrative authority may urge the foreign national to renounce their home country’s nationality after becoming a Japanese citizen.

② The Case of China

China generally does not permit dual nationality. Consequently, after being granted naturalization in Japan, it is necessary to renounce Chinese nationality.

The procedure for renouncing Chinese nationality is called the “Application for Loss of Nationality” (国籍喪失申請). It is handled by the Public Security Bureau’s Exit and Entry Administration Department within China, or by the Chinese Embassy or Consulate General if the applicant is abroad.

For the application, documents such as the Naturalization Permission Notice from Japan, a family register transcript (Koseki Tohon), passport, and identification documents must be submitted. The screening often takes several months, and once the renunciation is formally approved, a “Certificate of Loss of Nationality” (国籍喪失証明書) is issued. The issuance of this certificate formally proves the loss of Chinese nationality.

③ The Case of Indonesia

Indonesia also does not generally permit dual nationality. If you naturalize in Japan, the renunciation of Indonesian nationality is required.

The procedure primarily involves submitting an “Application for Renunciation of Nationality” (国籍離脱申請) to the Indonesian Ministry of Law and Human Rights. If residing abroad, the procedure can be completed through the Indonesian Embassy or Consulate General.

Required documents include proof related to the naturalization permission in Japan, the Indonesian passport, identification (KTP, Kartu Keluarga), and a birth certificate. Upon approval following the screening, a “Certificate of Loss of Nationality” (国籍喪失証明書) is issued, at which point Indonesian nationality is officially lost.

Thus, since neither China nor Indonesia permits dual nationality, foreign nationals from these countries who wish to naturalize in Japan must complete the necessary procedures to renounce their citizenship in their home country.

Summary of Nationality Renunciation Procedures

◎ Procedure for Renouncing Chinese Nationality

Item	Details
Procedure Flow	Fill out and submit the Chinese Nationality Renunciation Application Form along with the necessary documents.
Required Documents	Chinese Nationality Certificate, Proof of acquisition of foreign nationality (Japanese), Documents related to the reason for renunciation, and other documents deemed necessary by the authorities.
Screening & Approval	Screening is conducted by the Chinese Public Security Department (公安部) or a Chinese diplomatic mission abroad. Chinese nationality is lost upon approval.
Notes	Restrictions: Active public servants or military personnel may be restricted from renouncing their nationality. Duration: Screening may take several months to over a year. In Japan: Procedures are conducted at the Chinese Embassy or Consulate in Japan.

◎ Procedure for Renouncing Indonesian Nationality

Item	Details
Procedure Flow	Fill out the Application for Loss of Indonesian Nationality and submit it, along with the required documents, to the Ministry of Law and Human Rights.
Required Documents	Indonesian Nationality Certificate (KTP, Kartu Keluarga), Proof of acquisition of foreign nationality (Japanese), and other documents deemed necessary by the authorities.
Screening & Approval	Screening is conducted by the Ministry of Law and Human Rights. Indonesian nationality is lost upon approval.
Return of ID	After losing nationality, identification documents such as KTP and Kartu Keluarga must be returned.
Notes	Handling of Minors: Children under 18 years old follow the nationality of their parent and may retain Indonesian nationality even if they acquire a foreign nationality (if the parent’s nationality allows).