Koseki
surname · Latin script
Recorded for both men and women· direction only, no split published
/koʊsɛci/(machine-generated) pronunciation, model-generated
Koseki is a surname written in the Latin script, with more bearers in Japan than in any other country.
- JPJapan≈1 in 12K(inferred from the name graph)
- BRBrazil1 in 1.7M
- USUnited States1 in 3.3M
carrying the name, as counted by its national register where one exists and as Mondonomo estimates it elsewhere (marked ≈ and "est." on hover). One hue, darker where it is more common; hover a country for its figure.
- Japan (inferred from the name graph)
- Sources
- 66 (measured from records)
- ≈1 in 12K (inferred from the name graph)
≈11,000 people, est.
Highest-authority source
Japan, est.
measured from records inferred from the name graph
Meaning & origin
No verified etymology recorded for this name yet — the entries below are drawn from usage statistics and the name graph.
Attested across 2 languages in the etymology graph.
Where in the world(measured from records)
Koseki counted together with the spellings and other-language forms grouped with it. Where a register counted another spelling, the row names it.
Sorted by bearers: national registers' counts, and Mondonomo's estimates (≈, est.) where no register counts.
| Country | Most common spelling | Sources | |||
|---|---|---|---|---|---|
| JP Japan | ≈11,000 est. | ≈1 in 12K | — | Koseki | 66 |
| BR Brazil | 128 | 1 in 1.7M | 128 | — | — |
| US United States | 100 | 1 in 3.3M | 100 | Koseki | 45 |
| GB United Kingdom | ≈8 est. | ≈1 in 8.5M | — | Koseki | 11 |
| CA Canada | ≈4 est. | ≈1 in 8.5M | — | Koseki | 5 |
Exact figures are national registers' own counts, while figures marked ≈ and est. are Mondonomo’s estimates, counted from our sources and calibrated against those registers; hover one for how far to trust it in that country. A dash means neither exists.
Registers cited: Census Bureau — Surname Frequency 2010; IBGE — Censo 2022 Nomes no Brasil per-token lookup (v3 API, given+surname). Figures without a register are Mondonomo estimates; see Methodology.
Country figures for a list of names, at full precision, are available under licence rather than by scraping this table (how that works).
Other recorded senses(measured from records)
Koseki is also recorded in one other lexicon, as a different name or as an ordinary word. These are senses of the spelling, not of the name above.
In English, A Japanese family registry, recording the births, deaths, marriages, etc. in a particular household.
as a wordkaikki.org Wiktionary extract (IPA + transliterations)
Ordered by how much of this spelling's record each language holds, so a sense from a language the name is barely used in sits last rather than first.
Notable people with this name(measured from records)
- Koseki San'eib. 1787JPJapanese physician and scholar
- Yūji Kosekib. 1909JPJapanese composer (1909-1989)
- Tōichirō Kosekib. 1912JPJapanese sociologist
- Hiroshi Kosekib. 1919JPJapanese businessperson and banker (1919-2013)
- Hajime Kosekib. 1932JPJapanese actor and seiyū
- Kitarōb. 1948JPnot in their usual nameJapanese actor
- Momo Kosekib. 1982JPJapanese boxer
- Shōta Kosekib. 1991JPJapanese baseball player
- Yuuta Kosekib. 1995JPJapanese actor
- Haruhiko KosekiJPresearcher
The ten people covered by the most Wikipedia language editions — a proxy for cross-cultural notability, which favours historical and Western figures over equally prominent contemporary ones — shown by birth year. Source: Wikidata (CC0).
How to address them(machine-generated)
Evidence(measured from records)
Attested in 6 sources across 3 countries.
| Country | Register | Year | Count | Rank |
|---|---|---|---|---|
| BR Brazil | IBGE — Censo 2022 Nomes no Brasil per-token lookup (v3 API, given+surname) | — | 128 | #52,477 |
| US United States | Census Bureau — Surname Frequency 2010 | 2010 | 100 | #160,975 |
| US United States | wru Name Dictionary — US surnames, Census 2010 subset (Khanna et al.) | — | — | — |
Reference works 1
- Wikipedia surname tokens
These works list the name; their figures are licensed and are not reproduced here.
Register rows as of the 2026-10-09 data build.
Frequently asked questions
- How do you pronounce Koseki?
- A machine transcription gives /koʊsɛci/ (IPA) for Japanese.
- In which country does Koseki have the most bearers?
- Mondonomo estimates about 11 thousand people named Koseki in Japan, more than in any other country we hold, where it is most often spelled koseki.
- How common is the name Koseki?
- In Brazil, the national register counted 128 people named Koseki, about 1 in 1.7 million residents.
What do you want to know about Koseki?
Nobody replies to these one by one, but what readers ask decides what these pages answer next.
Query this name via API
curl -H "X-API-Key: YOUR_KEY" https://api.mondonomo.ai/api/v1/name-graph/kosekiThe payload this page is built from: spellings and scripts, countries and languages, related names, and the registers that attest the form. It takes a free API key (1,000 requests a day), which returns what this page shows everyone; the full country table, every register citation and the year-by-year series come with a licensed key, as does bulk access.
About this data
measured from records inferred from the name graph machine-generated
These figures come from the data snapshot of and will change as it is rebuilt.
Statistics are aggregated from the Mondonomo name corpus; related names and etymology are inferred from the name graph; pronunciation and any machine-marked transliterations are model-generated. Read how the numbers are made, including their known failure modes, and where the data comes from.
Reference works we consult — surname dictionaries, official name registers, Wikidata and Wiktionary — are named directly, beside the claims they support. The per-country source counts also include datasets of person records: we publish how many there are and their authority tier, but not their names.
Cite this page Mondonomo, “Koseki”. Data snapshot 2026-10-10.