Blood Type Distribution in Japan
Updated May 2026
Reference summary
Japan has one of the highest A blood type frequencies globally (about 38-40 percent) and one of the lowest Rh-negative frequencies (under 1 percent). The combination shapes the Japanese Red Cross donor strategy. The cultural ketsueki-gata belief that blood type predicts personality is influential in Japanese popular culture but has not survived empirical testing. This page summarises the published distribution data and the cultural context. It is not medical advice.
National distribution overview
The widely cited Japanese blood type distribution is approximately: A 38-40 percent, O 30-31 percent, B 20-22 percent, AB 9-10 percent. The Rh-positive rate is over 99 percent. These figures come from Japanese Red Cross donor data and from population studies published in the Japanese Journal of Transfusion and Cell Therapy and similar venues.
By global standards, Japan has unusually high A (and AB), unusually low Rh-negative, and a roughly intermediate B frequency (lower than India, higher than Europe). The combination is somewhat distinctive and is the basis of the cultural prominence of blood type as a social signal in Japanese society.
The exact figures vary slightly across studies and over time. The Japanese population is relatively homogeneous compared with multi-ethnic populations like the US or Brazil, so within-Japan regional variation is smaller than the variation between Japan and other countries.
Why Rh-negative is so rare
Rh-D allele frequencies are not uniform across human populations. In European-origin populations, the Rh-negative allele (technically the absence of the RHD gene, or specific deletions and mutations) is at intermediate frequency, around 40 percent. This produces a 15 percent Rh-negative phenotype rate in Europeans (because the phenotype is recessive: both copies of the gene need to be Rh-negative to produce the Rh-negative phenotype).
In East Asian populations including Japan, the Rh-negative allele is at very low frequency, with the result that less than 1 percent of the population is Rh-negative. The pattern reflects ancient population history and is shared across China, Korea, Japan, and much of Southeast Asia.
For transfusion services, the rarity of Rh-negative blood means a relatively small donor pool to support all Rh-negative recipients (trauma patients of unknown type, women of childbearing potential needing transfusion). The Japanese Red Cross runs targeted Rh-negative donor recruitment to maintain stocks. For a Rh-negative person living in Japan, donating regularly is particularly impactful given the small national pool.
The ketsueki-gata cultural belief
Japan is the home of the most influential cultural belief that blood type predicts personality. Ketsueki-gata (literally blood-type-style) traces to a 1927 paper by Tokeji Furukawa and was popularised by Masahiko Nomi in the 1970s. The framework assigns personality clusters to each ABO type and is widely featured in Japanese magazines, dating profiles, and morning television.
Type A is described as serious, organised, considerate. Type B is described as creative, passionate, individualistic, and (in less flattering versions) selfish or unreliable. Type O is described as confident, leader-like, optimistic. Type AB is described as rational, eccentric, dual-natured.
The belief has been tested in peer-reviewed studies. The 2015 Cho et al. PLOS ONE study tested 9,819 Japanese and American adults using standard Big Five personality inventories. No replicable correlation between ABO type and personality emerged after correction for multiple comparisons. The cultural belief is widespread and influential but does not survive empirical testing.
See our dedicated blood type personality page for the cultural origin and the published tests in detail.
Bura-hara: blood-type discrimination
The cultural prominence of ketsueki-gata has produced a recognised form of discrimination known as bura-hara (blood-type harassment, from the Japanese pronunciation of blood-type plus harassment). Type B individuals (described as selfish in the framework) and type AB individuals (described as eccentric) report being passed over for jobs or relationships because of their blood type.
The Japanese Ministry of Health, Labour and Welfare has periodically warned employers against using ABO information in hiring decisions. The phenomenon is taken seriously enough by Japanese psychologists and educators that mass-market kindergartens have been criticised for grouping children by blood type for social-skills training, with concerns about self-fulfilling prophecy effects.
The bura-hara concept does not have a direct equivalent outside Japan, although other cultural beliefs that label individuals by an immutable trait produce similar dynamics in other contexts.
Donating blood in Japan
The Japanese Red Cross Blood Service is the primary blood donation organisation in Japan. Eligibility is broadly similar to international standards: age 16-69 (16-17 with parental consent for whole blood, 18+ for plasma and platelets), minimum body weight 50 kg, haemoglobin minimum 12.0 g/dL for whole blood (12.5 g/dL for 400 mL whole blood), no infection or recent vaccination contraindications.
The standard donation volume options in Japan are 200 mL and 400 mL whole blood. Apheresis platelets and plasma donations are widely available in major centres. The donation interval for whole blood is 8 weeks (200 mL) or 12 weeks (400 mL for women) or 16 weeks (400 mL for men), reflecting the different proportional blood volume removed.
Foreign residents in Japan can donate, with eligibility checked via the Japanese Red Cross health questionnaire. Some donors are deferred based on history of residence in countries during specific periods (UK, France, and others during the vCJD risk window). The questionnaire is in Japanese; some major centres provide English-language support.
The Japanese Red Cross website (jrc.or.jp) is the official source for current eligibility, donation centre locations, and special drives. Specific Rh-negative donor recruitment is a continuing priority.
Comparison with other East Asian populations
Japan's very high A frequency is somewhat distinctive even within East Asia. Korea has a similar but slightly lower A frequency (about 32-34 percent). China shows substantial regional variation, with northern populations tending toward higher B and central populations showing more even distribution. Vietnam, Thailand, and the Philippines lean toward higher O and lower A than Japan.
The very low Rh-negative frequency is consistent across East Asia. The Rh-negative allele is uncommon throughout the region. This pattern is shared with Sub-Saharan African and Native American populations, where Rh-negative is also rare or absent in some groups. The high Rh-negative frequency in European populations is the global outlier.
See our distribution by ethnicity page and our blood type by country page for the wider comparative data.