総務省｜住民基本台帳等｜住民票、マイナンバーカード等への旧氏の併記について

This page explains the system allowing the notation of former surnames (kyuuji) on resident registers and My Number cards. Following an ordinance amendment effective November 5, 2019, individuals can officially record their previous surname alongside their current name after marriage or similar changes. This initiative supports women who continue using their maiden names professionally and socially. When a former surname is registered on a resident register, it automatically appears on the My Number card. Only one former surname per person is permitted, requiring a request procedure at the municipal office. As of December 10, 2025, submitting family register certificates is generally no longer necessary.