A name generator — ours for Chinese, Korean, Japanese, Thai, Malay and Indonesian names included — will hand you something that sounds right. A civil registrar decides whether it can be recorded, and those are different tests. Japan changed its rule last year in a way that makes the gap unusually visible: a reading that a parent likes is no longer sufficient, and the registrar may ask for documentary evidence that the reading exists.
Japan now registers how a name is pronounced
Japanese names are written in kanji, and kanji readings are not fixed. The same characters can be read several ways, and until recently the family register recorded only the characters. The reading lived in practice rather than in the record.
That changed on 26 May 2025 with the revised Family Register Act. Furigana, the phonetic reading of a name, became part of the register itself. For new births, the reading now goes on the birth notification, and it has to meet a standard: it must be a reading generally accepted as a way of reading those characters in a name. Where a registrar cannot confirm that, they may ask for supporting material — dictionaries, newspapers, magazines or other publicly distributed publications showing the reading in use.
That is the sentence a name generator cannot satisfy. A tool can produce a plausible character combination and attach a reading that no dictionary carries, and the counter is where that gets found out.
The part that catches people who did nothing
Existing registrants were given a window to notify their own reading, and that window has closed — it ended on 25 May 2026. If you are reading this expecting to file something, the moment has passed.
The consequence for anyone who did not notify is counterintuitive. For anyone who did not notify, the municipality recorded a reading on their behalf, taken from the notice that was mailed out in advance. Those people may change that recorded reading once, by notification alone, without going to court.
Anyone who did notify a reading is in the stricter position: changing it later requires family court permission. The person who complied has the harder path, and the person who ignored the letter kept a free correction. This is not an argument for ignoring official letters, just a statement of how the rule works.
Korea expanded its character list, and did not lift its length limit
Korean given names in the family register may use hanja only from a permitted list maintained by the Supreme Court. In a decision of 23 May 2024, effective 11 June 2024, that list grew from 8,319 characters to 9,389 — an addition of 1,070.
A second change is narrower than it is usually reported. From 20 June 2025, the five-character limit on given names was lifted for children of Korean-foreign couples registered under the foreign parent's home-country register, extending an allowance that previously covered only foreign-father and Korean-mother cases. The general five-character limit still applies to everybody else. Korea did not abolish its name-length rule; it widened one exception.
Thailand requires your surname to be unique, and short
Two conditions in Thailand's Person Name Act of 1962 are important when creating a new surname. A new surname may not duplicate one already registered or one granted by the King. And it may not exceed ten consonants.
The two rules pull against each other. Uniqueness across a whole country pushes toward longer, more distinctive constructions; the cap pushes back.
You will often read that Thai surnames are long because the short combinations were claimed first, leaving later families to build longer ones. It is a satisfying story, but we couldn't find any scholarly sources to support it. It rests on general-interest sources rather than scholarship, it sits awkwardly with the chronology — the uniqueness requirement came from a 1913 act while the length cap arrived in 1962 — and the statute as it stands limits length rather than encouraging it. The rules are checkable; the explanation is folklore, and we have left it out.
Vietnam bars numerals, and is broader about language than usually stated
Vietnam's Civil Code provides that a child's surname is the father's or the mother's by agreement between the parents, with custom as the fallback where there is no agreement.
On the given name, the common summary is that it must be Vietnamese. The provision is wider: for a Vietnamese citizen the name must be in Vietnamese or in another ethnic-minority language of Vietnam. It also forbids naming by numerals, or by any character that is not a letter.
Those last two prohibitions are the ones a generated name can trip over, particularly anything that renders a name with a digit or a symbol in it.
Indonesia discourages one-word names without forbidding them
Indonesian civil-registration guidance since 2022 asks for a name of at least two words, within a limit of sixty characters including spaces, readable, and without a negative meaning.
The two-word rule is widely reported as mandatory and it is not. The administering directorate has stated that a single-word name is discouraged, but that if the applicant insists on one word it is permitted and will still be written into the population documents. The distinction is important for anyone with a one-word name, which is common. It is the sort of detail that gets lost when a guideline is repeated as a prohibition.
Malaysia leaves it to an official's judgement
Malaysia's registration law gives the Registrar-General discretion rather than a list. Where a name appears objectionable or undesirable, the registrar refers it upward, and the Registrar-General may register it or decline to as he sees fit.
Lists of specifically banned names do circulate — titles, animals, fruit, objects, certain abbreviations — and they are widely reported. We have not been able to locate them in any published departmental document, so they are described here as reported rather than stated as rules. The statutory position is the registrar's discretion. That is what you can rely on, not the circulating lists.
Where this comes from, and what will date
The Japanese material is from the Ministry of Justice's own furigana pages, the Korean from Supreme Court press releases, the Thai from the Person Name Act's text, the Vietnamese from the Civil Code, the Indonesian from the administering directorate's published guidance, and the Malaysian from the Births and Deaths Registration Act.
Six jurisdictions means six independent clocks. Korea's permitted list has been revised repeatedly and will be again; Japan's transitional provisions are already spent; Indonesian guidance is guidance and can be restated. Every rule here should be confirmed with the registry before anyone acts on it, which is advice we would give even if the guide were a week old.
What this is not. It is a description of what registries do, not advice on what to name a child, and it deliberately avoids the areas where naming rules intersect with religious registration and personal-status law. Those are live legal questions in more than one of these countries and they are not an aside in a guide about name generators.
