๐ How Rare Are You in Japan?
๐ฏ๐ต Genetic Landscape of Japan
Japan is one of the most genetically homogeneous major nations, with over 98% of the population sharing Yamato Japanese ancestry. Two ancient groups โ Jลmon (indigenous hunter-gatherers) and Yayoi (rice farmers from mainland Asia) โ merged to form modern Japanese. The Ainu people of Hokkaido carry distinct genetic markers including wavy hair and more body hair. Okinawans have their own unique genetic profile closer to ancient Jลmon. Blood type is culturally significant in Japan โ "blood type personality" is widely discussed in media and dating. A+ blood type is most common, unlike the global O+ dominance.
Names, rather than looks, are where rarity is easiest to read here. Commoners were barred from using surnames in public until the Meiji government required every household to register one in the 1870s, so most families chose theirs at roughly the same moment, and chose from what was in front of them: rice paddies, river mouths, wooded slopes. The result is an enormous stock of surnames that never travelled far from home. Okinawan names such as Higa, Kinjล and Chinen stay concentrated in the south, while Hokkaidล's map is mostly Ainu words written in borrowed characters. Readings complicate things further, since the same two kanji may be pronounced several ways โ two people can share a written name and not a spoken one.
๐ The Seventeen Things the Census Asks
Japan’s Population Census counted the country as of 1 October 2025, and it asks 17 things — thirteen about each person, four about the household. The personal ones include your name, the year and month you were born, your relationship to the head of the household, your nationality, how long you have lived at your current address, where you lived five years before, and whether you are working. Ethnicity is not among them. Neither is race, religion, nor any physical characteristic.
That is why this page can be firm about some numbers and not others. Nationality is counted, so the population total is solid. Ancestry is not, so any headcount for the Ainu has to come from somewhere else: a living-conditions survey run by Hokkaido prefecture, which counts only people who say so themselves. The 2013 round, the one the Ainu Association of Hokkaido cites, found 16,786 people across 66 municipalities. The Association says the real figure is far higher, partly because the survey reached Hokkaido residents only.
๐๏ธ Eye Color
| Dark Brown | 70% |
| Brown | 25% |
| Black | 4% |
| Other | 1% |
๐ Hair Color
| Black | 85% |
| Dark Brown | 12% |
| Brown | 2% |
| Other | 1% |
๐ฉธ Blood Type
| A+ | 30% |
| O+ | 29% |
| B+ | 20% |
| AB+ | 10% |
| A- | 5% |
| O- | 3% |
| B- | 2% |
| AB- | 1% |
Trait frequencies on this page come from public and institutional datasets โ see Data Sources.
🧮 Calculate Your Rarity in Japan
Pick your eye colour, hair colour and blood type. The calculator uses Japan'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 →
๐ When the Register Learned to Say Your Name
Until 26 May 2025 the koseki — the family register every Japanese citizen appears in — held the characters of a person’s name and nothing certified about how to pronounce them. The law that changed that is Act No. 48 of 2023, passed on 2 June 2023 and promulgated on the 9th. When it took effect on that day in May, a katakana reading became a registered item.
Everyone then had one year to tell their municipality which reading was theirs. Filing cost nothing, and the Justice Ministry warned that anyone demanding money for it — on the story that the filing carries a fee, or that skipping it carries a fine — was running a scam. The window shut on 25 May 2026; where nobody filed, the mayor of the municipality enters a reading instead. So the question this site keeps asking — do two people have the same name? — has had an official spoken half in Japan for about sixteen months.
๐ฉธ The Question a Labour Bureau Wrote Down
The Kumamoto Labour Bureau, an office of the Ministry of Health, Labour and Welfare, publishes a list of questions employers should not put to job applicants. Under the heading for other matters needing care, just after ใใฟใใณใๅธใฃใใใจใใใใพใใ?ใ and just before ใ็ญๆใฏใชใใงใใ?ใ, sits ใ่กๆถฒๅใปๆๅบงใฏไฝใงใใ?ใ — what is your blood type and star sign? The same list also carries ใๅฝผๆฐ(ๅฝผๅฅณ)ใฏใใพใใ?ใ.
The belief behind that question has been tested. Kengo Nawata, writing in The Japanese Journal of Psychology in 2014 (vol. 85, no. 2, pp. 148–156), describes it as a widespread popular belief in Japan and went looking for it in two Japanese samples from 2004 and 2005 and an American one — over 10,000 people in all, by the paper’s own count. Of 68 personality items, 65 showed no significant difference between blood groups, and the effect sizes came in under η² = .003 — blood type accounted for less than 0.3% of the variation.
โญ Rare Facts About Japan
Which of these numbers has a publisher
The population is the 2025 Population Census from the Statistics Bureau, Ministry of Internal Affairs and Communications: 123.05 million as of 1 October 2025. Blood type starts from the Japanese Red Cross Society, which gives the four-way A/O/B/AB split and puts Rh-negative near 0.5 per cent. Height is the Ministry of Health, Labour and Welfare’s National Health and Nutrition Survey, which measures people at a venue rather than asking them. No Japanese census or national health survey records eye or hair colour, so those rows are illustrative estimates. See Data Sources. Last checked September 2026.