Kosei
A boy's name of Japanese origin with 90 recorded U.S. births.
Meaning & Origin
Only 90 babies have been named Kosei in recorded U.S. history. That level of rarity means your child would almost certainly be the only one in their school, their workplace, and most rooms they walk into — a genuinely one-of-a-kind choice.
Kosei is not in the current top 1,000 boy names nationally, making it an uncommon choice — though your state or community may differ.
Kosei is a boy's baby name of Japanese origin, commonly written with kanji meaning 'justice' and 'life' or 'fairness' and 'star.' The name reflects the Japanese value of kosei — individuality and fairness.
Kosei is clean and balanced — a two-syllable name that carries deep moral meaning in its culture of origin.
EtymologyShow more
Kosei first shows up in U.S. Social Security records in 2000. First appearing in the 2000s, Kosei emerged during a period of rapid naming innovation in America, when parents increasingly created new names or adopted them from global cultures.
Its Japanese classification suggests a path from japanese linguistic traditions into American usage, though the specific route — whether through immigration, literature, or cultural exchange — would require deeper historical research.
At a Glance
Popularity Over Time
Kosei has 16+ years of history in the U.S., first appearing in 2000.
Popularity by Decade
| Decade | Births | Avg Rank | Trend |
|---|---|---|---|
| 2020s | 7 | #10145 | ▼ |
| 2010s | 43 | #12657 | ▲ |
| 2000s | 40 | #11593 | — |
The Story of Kosei
A Gen Z name
Peaking in 2008, Kosei is a name that defines a generation. Boys named Kosei are most likely born between 2000 and 2018.
How rare is Kosei?
With fewer than 500 recorded births, Kosei is an exceptionally rare name — a one-of-a-kind choice.
The journey through the decades
First appeared in the records in 2000, peaked in the 2010s with 43 births that decade, and has since become a rare, vintage choice.
Kosei by the numbers
- Would fill 2 school buses
Year-by-Year Data
View complete yearly data(16 years, 2000–2020)
| Year | Births | Rank |
|---|---|---|
| 2020 | 7 | #10145 |
| 2019 | 5 | #13236 |
| 2018 | 6 | #11554 |
| 2016 | 5 | #13347 |
| 2014 | 5 | #13182 |
| 2013 | 6 | #11545 |
| 2012 | 5 | #13349 |
| 2011 | 5 | #13463 |
| 2010 | 6 | #11576 |
| 2009 | 6 | #11824 |
| 2008 | 9 | #8703 |
| 2006 | 5 | #13158 |
| 2004 | 5 | #12404 |
| 2003 | 5 | #11949 |
| 2002 | 5 | #11708 |
| 2000 | 5 | #11406 |
Source: U.S. Social Security Administration. Showing years with 5+ recorded births.
Frequently Asked Questions
Is Kosei a boy's or girl's name?
When was Kosei most popular?
How popular is the name Kosei?
Explore More
Data source: U.S. Social Security Administration, 2000–2020