This article examines the changes to Japanese civil law that came into effect on April 1, 2026. These changes are aimed at shifting from the traditional model of sole custody after divorce to a more flexible system that allows for the continued participation of both parents in raising children and the significance of this system in transforming the concept of parental authority. The adoption of these amendments resulted from an internal evolution of views on the nature of parental rights and responsibilities and is also associated with the growing influence of international standards for the protection of children's rights. These changes implement a comprehensive approach to regulating family relations, aimed at prioritizing the protection of the child's interests, taking into account the determination of the child's communication with parents and the development of mechanisms for ensuring their maintenance, including alimony obligations. Family reform affects not only the normative level of regulation but also issues related to the mechanisms for its implementation, which requires a rethinking of existing law enforcement approaches.