We reported on our comparative study of joint custody (kyodo-shinken in Japanese) at the Taipei-Tokyo Bar Associations’ seminar. Subsequently, the amended Civil Code of Japan was enforced on 1 April 2026, introducing significant changes to family law.
Key Updates from the Newly Enforced Civil Code: Please note the following important changes regarding child custody that came into effect on 1 April 2026:
- Joint Custody Decisions and Family Court Intervention: Divorcing parents can choose joint or sole custody through mutual agreement. Now, the divorce notification filed at the local ward office includes a section to indicate the choice of joint custody. (Note for foreign readers: Under the Japanese Civil Code, a marriage can be legally dissolved simply by submitting a divorce notification mutually signed by the divorcing couple, along with the signatures of two adult witnesses. No other procedures, such as court intervention or religious proof from a church, are required.) However, if they cannot agree, the Family Court will intervene and decide based on the “best interests of the child.”
- Disadvantages for Domestic Violence Perpetrators: The Family Court must mandate sole custody (tandoku-shinken in Japanese) if there is a risk of domestic violence (DV) or child abuse, or if it is deemed difficult for the parents to exercise joint custody. Consequently, perpetrators of DV will be disadvantaged as they will not be granted joint custody.
- Decision-Making Rules Under Joint Custody: If joint custody is chosen, not every decision requires mutual consent. The law clearly distinguishes between matters requiring agreement and those that can be decided solely:
- General Rule (Important Matters): Mutual agreement is required for decisions that significantly impact the child’s life or future (e.g., relocation/moving, choosing schools, or major medical treatments).
- Exceptions (Sole Decision-Making): A parent can act independently without the other parent’s consent in two scenarios:
- Daily Needs & Education: Minor day-to-day matters generally handled by the co-residing parent (e.g., meals, clothing, extracurricular activities, routine vaccinations, or short trips).
- Urgent Circumstances: When immediate action is necessary for the child’s best interests (e.g., relocating to escape DV or child abuse—which makes taking the child without permission legally permissible—emergency medical treatments, or imminent school enrollment deadlines).
- (Note: If parents are deadlocked on an important matter, they can petition the Family Court to grant one parent the sole authority to decide on that specific issue.)
- Decision-Making Rules Under Joint Custody: If joint custody is chosen, not every decision requires mutual consent. The law clearly distinguishes between matters requiring agreement and those that can be decided solely:
The above is a brief overview of the changes. As the burden on the Family Court’s judgment will increase significantly—especially regarding the presence or absence of domestic violence (DV)— we will be closely monitoring future developments in legal practice.
(5 April 2026)