Blood-type personality tool. Pick A / B / O / AB to see that type's essence, strengths, weaknesses, social & work style, and best-matched type(s). Optionally add a second person to see what the lore says about the pair. From Japanese pop culture — entertainment only, no scientific basis.
Blood Type Personality
How to use
Pick your blood type
Tap A, B, O, or AB. The tool instantly shows our summary of the profile that Japanese blood-type lore (血液型性格分類) gives that type. No submit, no network.
Read the personality profile
You get a one-line "essence", 4–5 strengths, 3–4 weaknesses, plus a social-style and work-style note: the stereotype attached to that type.
See the lore's best match
Each profile lists the types the lore calls "most compatible", read straight from the pair notes in step 4, so the two always agree. It is a pop-culture notion only, not a basis for choosing a partner or friend.
(Optional) Compare a second person
Pick a second person's blood type on the right and the tool adds what the lore says about that pair. Read it for fun and move on: it is the lore's claim, not a finding.
Blood-Type Personality: a 1927 Paper and a 1970s Craze
"What's your blood type?" In Japan the question can work the way "What's your star sign?" does elsewhere, as an easy icebreaker. The belief, known in Japanese as 血液型性格分類 (ketsueki-gata seikaku bunrui), holds that the four ABO blood groups map onto personality: A careful and reserved, B free-spirited, O optimistic and practical, AB rational and many-sided. In Japan it has filled books and TV segments. The profiles and pair notes in this tool are our own summary of those widely repeated stereotypes, not quotations from any one source, and they are here for light fun.
Furukawa's paper and Nomi's books
In 1927 Takeji Furukawa, of the Tokyo Higher Normal School for Women, published a paper on blood type and temperament in the Japanese Journal of Psychology, an early study that drew wide attention. By his own account it began with 11 of his relatives, then 50 colleagues and friends, then 269 students, 248 of whom answered, and he called it a first attempt with many shortcomings. The modern craze is traced to a 1971 book by the writer Masahiko Nomi, 『血液型でわかる相性』. Japan's National Diet Library catalogue lists about a dozen blood-type titles from him in the ten years to his death in 1981.
Large studies since have found the link to be tiny at most. Kengo Nawata's 2014 study used social surveys from Japan and the United States: 11,729 questionnaires came back, and the analyses used the nearly 9,700 respondents who gave a blood type (9,533 to 9,722, depending on the question), about 3,000 of them American. The questions came from an economics survey of attitudes to life and money: some 29 distinct questions across the three surveys, 68 tests in all. In 65 of the 68 blood type made no significant difference, and in every one it accounted for less than 0.3% of the variation in answers. In 2015 a team led by Tsuchimine genotyped 1,427 Japanese adults and found a statistically significant but weak association with one trait, persistence, which the authors called preliminary and asked readers to interpret with caution. Neither result comes anywhere near a personality you could read from a blood type.
"Blood-type personality is a fun cultural mirror: it reflects social imagination, not biological fact."
Why it can seem to fit, and why it must not be used to judge anyone
Some of the studies Nawata reviews suggest belief itself does part of the work. Yamaoka (1999, 2006) found blood-type differences among people who believe in the typing and almost none among those who do not, and Sakamoto and Yamazaki (2004), using data from 1978 to 1988, found type-A respondents drifting toward the type-A stereotype over the years, which they read as a self-fulfilling prophecy. Nawata's own random samples from the 2000s, however, showed no such differences. Its harmless use is as a conversation starter. The harm is on record. On 8 December 2004 the youth committee of Japan's Broadcasting Ethics & Program Improvement Organization (BPO) asked broadcasters not to promote the idea that blood type decides personality, warning that classifying and valuing people by a blood type they cannot change risks leading to social discrimination. The viewer letters it published alongside included a report of bullying at a child's school ("you must be type B") and a complaint that the equation "bad personality = type B" was hurtful. That is the stereotype type B carries in Japan, and the cheerful type-B profile above does not show it. It is why this tool keeps repeating that it is entertainment only and must never be used to judge, hire, or make medical decisions.
The 2004 broadcast-ethics request that cited "you must be type B" bullying at school
On 8 December 2004 the youth committee of Japan's Broadcasting Ethics & Program Improvement Organization (BPO) asked broadcasters not to promote the idea that blood type decides personality, warning that sorting people by a blood type they cannot change risks leading to social discrimination. One of the viewer letters it published alongside reported that bullying had started at a child's school: "you must be type B".
Takeji Furukawa's 1927 paper on blood type and temperament rested first on 11 of his own relatives, then 50 colleagues and friends, then 269 students, of whom 248 answered. In his foreword he called it a first attempt with many shortcomings.
The modern craze is usually traced to the writer Masahiko Nomi's 1971 book 『血液型でわかる相性』. Japan's National Diet Library catalogue lists about a dozen blood-type titles from him in the ten years to his death in 1981; two 1979 subtitles sell the idea as "science".
Kengo Nawata's 2014 study used social surveys from Japan (2004 and 2005) and the US (2004): 11,729 questionnaires came back, and nearly 9,700 respondents who gave a blood type were analysed. Across some 29 questions on attitudes to life and money, 65 of 68 tests showed no significant difference, and in every one blood type accounted for less than 0.3% of the variation in answers.
Three "significant" results in 68 tests is what chance alone would be expected to throw up: Nawata puts the probability of 3 or more at 66.7%, with 3.40 expected. On one of them, worrying about one's children's future, type AB scored highest in Japan and lowest in the US.
In 2015 Tsuchimine and colleagues genotyped the blood type of 1,427 Japanese adults rather than asking for it, and found a significant but weak association with one trait, persistence. The authors wrote that the result should be regarded as preliminary and interpreted with caution, because the association may be relatively weak.
Studies Nawata reviews suggest belief itself is at work: Yamaoka (1999, 2006) found differences among people who believe in blood-type typing and almost none among those who do not, and Sakamoto and Yamazaki (2004) found type-A respondents drifting toward the type-A stereotype between 1978 and 1988. Nawata's own random samples from the 2000s showed no such differences.
An earlier Japanese analysis Nawata cites, Matsui (1991), covered 12,418 people across surveys in 1980, 1982, 1986 and 1988. Only 1 of 24 items differed significantly in all four years, and the highest-scoring type changed from year to year.
The largest blood group differs across Asia, and the sources measure different things. In the Japanese Red Cross's approximate population shares, type A is the largest group in Japan at about 40%; the Korean Red Cross's population estimate puts type A at about 34%. Among Singapore's 2025 blood donors (HSA), 44.7% were type O; among Malaysia's 2025 donations at 22 Ministry of Health sites, where a repeat donor counts each time, 42.7% were type O. The four figures cannot be ranked against each other.
ABO antigens are not only on red blood cells but also on other cells, such as those lining blood vessels and epithelial cells (Korean Red Cross), which is why ABO matters for transplants as well as transfusion. That is what blood type is actually used for in medicine.
Frequently Asked Questions
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No. No study has shown that blood type decides personality. In Kengo Nawata's 2014 analysis of surveys from Japan and the US, blood type made no significant difference in 65 of 68 tests and accounted for less than 0.3% of the variation in answers in every one. A 2015 study that genotyped 1,427 Japanese adults found a weak link to one trait, persistence, which its authors call preliminary. Every description here is a pop-culture stereotype, for entertainment only.
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Its popular form is Japanese. An early Japanese study that drew wide attention was Takeji Furukawa's 1927 paper on blood type and temperament, built on 11 of his relatives, 50 colleagues and friends, and 248 student answers. The modern craze is traced to the writer Masahiko Nomi's 1971 book 『血液型でわかる相性』, followed by about a dozen more from him over the next decade.
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Partly because belief can shape the answers. Studies Nawata reviews found blood-type differences among people who believe in the typing and almost none among those who do not (Yamaoka, 1999 and 2006), and type-A respondents drifting toward the type-A stereotype between 1978 and 1988 (Sakamoto and Yamazaki, 2004). The profiles here are also written broadly, so most readers will find something that fits.
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Absolutely not. In 2004 the youth committee of Japan's Broadcasting Ethics & Program Improvement Organization (BPO) warned that classifying and valuing people by a blood type they cannot change risks leading to social discrimination, and published viewer letters that included a report of a child bullied at school as "type B". Treat blood-type matching as a joke. Real relationships and hiring decisions should rest on knowing the person and on actual ability.
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The notes are our own summary of popular Japanese blood-type lore, written once and fixed: no randomness, no algorithm, no scientific basis. The "best match, according to the lore" line in each profile is read from the same notes, so the two can never disagree.
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There is no "best" blood type. Each stereotype here carries strengths and weaknesses alike, and none of them is a measure of personality.
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ABO and Rh types matter for the safety of transfusions, organ transplants and pregnancy compatibility, where a mismatch can be life-threatening. ABO antigens are not only on red blood cells but also on other cells, such as those lining blood vessels (Korean Red Cross), which is why ABO matters for transplants too. That is blood type's real use, and it has nothing to do with personality.
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Just pick any one for fun — this is only entertainment. If you genuinely need your real type (for medical reasons), get it via blood donation, a health check, or a proper medical lab — never guess from online claims or appearance.
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No. Everything is built into the page and shown in your browser the moment you choose. Your selection is not stored or sent to our servers.
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Yes — as a social topic and cultural entertainment. Like astrology or the zodiac, it makes a relaxed icebreaker at gatherings and first meetings, with harmless fun. As long as you know it isn't science and don't use it to label or judge people, enjoying the cultural novelty is perfectly fine.
Sources and method
Nawata's questions come from an economics survey about attitudes to life and money, not a standard personality test, a limit the paper itself states; blood type was self-reported, and the number analysed varies by question. The Japan and Korea figures are population estimates, Singapore's is a share of donors and Malaysia's a share of donations, so the four cannot be ranked against each other. The personality profiles and pair notes are our own summary of popular lore; they assert nothing, so they cite nothing.
- Kengo Nawata (2014), 血液型と性格の無関連性 (the unrelatedness of blood type and personality: evidence from large-scale surveys in Japan and the US), Japanese Journal of Psychology 85(2):148–156, doi:10.4992/jjpsy.85.13016. Respondent counts, the 68 tests, effect sizes and the chance calculation; Matsui (1991), Yamaoka (1999, 2006) and Sakamoto & Yamazaki (2004) as Nawata reports them. www.jstage.jst.go.jp
- Tsuchimine S. et al. (2015), PLoS One, doi:10.1371/journal.pone.0126983. 1,427 Japanese adults, blood type genotyped, Temperament and Character Inventory; a weak association with Persistence that the authors call preliminary. pmc.ncbi.nlm.nih.gov
- Takeji Furukawa (1927), 血液型による氣質の研究 (a study of temperament by blood type), Japanese Journal of Psychology 2(4):612–634. His own sample counts and his description of the work as a first attempt. doi.org
- National Diet Library catalogue: Masahiko Nomi (1925–1981), 血液型でわかる相性, Seishun Shuppansha, 1971. The count of about a dozen titles from 1971 to 1981 is ours, from the same catalogue. ndlsearch.ndl.go.jp
- BPO (Broadcasting Ethics & Program Improvement Organization) Youth Committee, request concerning programmes that deal with blood type, 8 December 2004. The discrimination warning, and the viewer letters quoted on this page (viewers' own statements, not findings). www.bpo.gr.jp
- Japanese Red Cross, Hyogo Blood Centre: approximate share of Japanese people by ABO type (a population estimate). www.bs.jrc.or.jp
- Korean Red Cross Blood Services: approximate shares of Koreans by ABO type (a population estimate), and ABO antigens on cells other than red blood cells. www.bloodinfo.net
- Health Sciences Authority, Singapore, Blood facts and figures (updated 31 May 2026): share of 2025 donors by blood group, with Rh-positive and Rh-negative summed by us. www.hsa.gov.sg
- Ministry of Health Malaysia and the National Blood Centre, open data, blood donations, CC BY 4.0 (data to 6 October 2026): share of 2025 donations by blood group at 22 Ministry of Health sites, our arithmetic. data.moh.gov.my
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