๐ How Rare Are You in South Korea?
๐ฐ๐ท Genetic Landscape of South Korea
South Korea is one of the most genetically homogeneous nations on Earth โ over 96% of the population shares dark brown eyes and black hair. This means that any deviation from these traits is extraordinarily rare. What makes Korean genetics fascinating is the unusually high AB blood type frequency (11%, compared to ~4% globally) and the virtual absence of Rh-negative blood. Korea's genetic uniformity comes from thousands of years of geographic isolation on the Korean Peninsula.
Rarity here is not only a matter of physical traits โ it also shows up in names. The clan system known as bon-gwan ties a surname to the ancestral seat it came from, so two people named Kim may belong to entirely different lineages traced to different towns. A handful of surnames dominate the country: Kim, Lee and Park together account for close to half the population, which makes an uncommon family name noticeable in any classroom. Jeju Island, cut off from the mainland for most of its history, kept its own speech, its own founding myth of three ancestors who rose out of the ground, and clan seats belonging to the island alone. Given names follow their own rule: siblings and cousins often share a generational syllable drawn from hanja.
๐ The statute that decides which age is your age
In South Korea, how old you are has a legal answer. The Ministry of Government Legislation records that rules for calculating and stating ๋ง ๋์ด โ full years counted from the date of birth โ were written into the Civil Act (๋ฏผ๋ฒ) and the Framework Act on Administration (ํ์ ๊ธฐ๋ณธ๋ฒ). The National Assembly passed the change in December 2022 and it took effect in 2023.
That is unusually concrete for something a rarity page takes for granted. Every age percentile on this site, including the one behind our birthday rarity tool, rests on a single definition of age. In South Korea that definition is not a convention you can argue about; for anything the state does, it is written into statute.
๐๏ธ Eye Color
| Dark Brown | 96% |
| Brown | 3% |
| Other | 1% |
๐ Hair Color
| Black | 97% |
| Dark Brown | 2% |
| Other | 1% |
๐ฉธ Blood Type
| A+ | 34% |
| O+ | 27% |
| B+ | 27% |
| AB+ | 11% |
| Rh- | <1% |
Trait frequencies on this page come from public and institutional datasets โ see Data Sources.
🧮 Calculate Your Rarity in South Korea
Pick your eye colour, hair colour and blood type. The calculator uses South Korea's own figures from the tables above, not world averages.
This is an estimate, not a measurement. It multiplies three national frequencies as if they were independent, and they are not: eye and hair colour share pigmentation genes, so a combination that tends to run together, such as blue eyes with blonde hair, is more common than the multiplication suggests, while one that rarely does, such as blue eyes with black hair, is rarer. Blood type is independent of both. The frequencies are national averages from public datasets — see Data Sources.
That number describes the body you were born with. Fraeon, our other site, does the same arithmetic for the part you chose: the films, series, games, books, anime and manga you have actually finished. Start your log →
โ๏ธ The character set a given name has to come from
A Korean given name cannot be written with whatever character its parents like. Article 44(3) of the Act on Registration of Family Relations (๊ฐ์กฑ๊ด๊ณ์ ๋ฑ๋ก ๋ฑ์ ๊ดํ ๋ฒ๋ฅ ) says a child's name must use hangul or hanja in common use, and that the range of hanja in common use is set by Supreme Court Regulation. So the state does not approve names one at a time; it fixes the set of characters a name may be built from.
It has a start date. The National Institute of Korean Language's journal ์๊ตญ์ด์ํ recorded in its Summer 1991 issue that the Supreme Court sent 2,731 characters to the Ministry of Culture for review, settled the range of hanja for names at 2,854, and brought it into force on 1 April under the Enforcement Rules of the Family Register Act (ํธ์ ๋ฒ ์ํ๊ท์น). We are not giving the size of the list today: we could not open a court source that states it, so it is left out rather than guessed.
โ๏ธ A surname that begins in a family court
The bon-gwan, the ancestral seat attached to a Korean surname, is not a closed list from the deep past. Article 96(1) of the Act on Registration of Family Relations covers a person who acquired Korean nationality, uses a foreign surname, and wants to set a new ์ฑ (surname) and ๋ณธ (clan seat) instead. They must get permission from the Family Court with jurisdiction over their registry base, their address, or the place they intend to make it, then report the new surname and seat within one month of receiving the certified copy of the decision.
So the register of Korean surnames is still open, and what opens it is a judge. That is worth knowing on a page about rarity: surname frequency is usually treated as history, and here it is also administrative law with a filing deadline. How many seats have been created this way, we do not know: we could not source a count, so none is given.
โญ Rare Facts About South Korea
Where the South Korean numbers on this page come from
Population here is published by the Ministry of Data and Statistics (๊ตญ๊ฐ๋ฐ์ดํฐ์ฒ) through KOSIS. Blood type shares come from Korean Red Cross Blood Services (๋ํ์ ์ญ์์ฌ ํ์ก๊ด๋ฆฌ๋ณธ๋ถ), which publishes a statistical yearbook โ donor figures, not a random sample. The height figure is not attributed to a named survey. The eye and hair colour percentages are estimates, not official statistics: we have no Korean government source for either. Last checked September 2026.