Japanese parents have wide freedom to choose a name, but within firm limits. A birth must be registered within 14 days, and the name goes into the family register (koseki), the official record of every Japanese citizen.
The allowed characters
A given name can use hiragana, katakana and about 3,000 kanji: the 2,136 jōyō kanji taught for everyday use and 863 jinmeiyō kanji approved specially for names. Kanji outside those lists cannot be registered, even common-looking ones. 儚 (fleeting), for example, is not allowed, which is why a name built on it can only exist as a pen name. Our meaning pages flag kanji that cannot be used.
Readings must now be registered
Until recently the family register held only the written name, so parents could read the kanji however they liked. From 26 May 2025, the reading of every name is recorded too, and new readings must be ones generally accepted for the kanji. The change came after years of debate about kirakira names, whose readings could be impossible to guess.
Names that were refused
In 1993 a father tried to register his son as 悪魔 (Akuma, devil). The local office refused, the case went to court and became national news, and the family eventually chose a different name. The case is still cited as the line between a parent's freedom and a child's welfare.
Changing a name later
Changing a given name needs the approval of a family court and a good reason, such as a name that causes real hardship. In 2019 a young man named 王子様 (Ōjisama, prince) changed his name after turning eighteen, saying it had made life difficult, and his story was widely shared.