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Japanese blood type theory of personality

Japanese Blood Type Personality Chart
Type A
Best Traits: Earnest, creative, sensible.
Worst Traits: Fastidious, overearnest.
Type B
Best Traits: Wild, a doer, cheerful.
Worst Traits: Selfish, irresponsible.
Type AB
Best Traits: Cool, controlled, rational.
Worst Traits: Critical, indecisive.
Type O
Best Traits: Agreeable, sociable, an optimist.
Worst Traits: Vain, careless.

The blood type theory of personality is a popular belief in Japan that a person's ABO blood type or ketsueki-gata (血液型?) is predictive of their personality, temperament, and compatibility with others, similar to the Western world's astrology. This belief has carried over to some extent in other parts of East Asia such as South Korea and Taiwan. This theory is completely dismissed by many scientists as superstition or pseudoscience.[1]



The ABO blood group system is widely credited to have been discovered by the Austrian scientist Karl Landsteiner, who found three different blood types in 1900.[2] Ethnic studies did show different blood group distributions across the world (e.g. Asian people having a higher percentage of Type B). This fact was used by early Nazis to further ideas of supremacy over different races.[1] Those distortions were debunked before Nazi Germany invoked race laws like the Nuremberg Laws, where the wording "German blood" is figurative for Aryan lineage.

The theory first reached Japan in 1927 in Takeji Furukawa's paper "The Study of Temperament Through Blood Type" in the scholarly journal Psychological Research. He was a professor at Tokyo Women's Teacher's School. The idea quickly took off with the Japanese public despite his lack of credentials, and the militarist government of the time commissioned a study aimed at breeding the soldiers.[1] The study used no more than ten to twenty people for the investigation. The breeding program therefore ended up with miserable results - most of the army selected by the project lost their lives. In another study, Furukawa compared the distribution of blood types among two different ethnic groups, the Formosans in Taiwan and the Ainu who live in Northeast Asia, especially Hokkaidō. His motivation for the study appears to have derived from a political incident.[3] After the Japanese occupation of Taiwan following Japan's victory over China in 1895, the inhabitants tenaciously resisted their occupiers. Insurgencies in 1930 and in 1931 killed hundreds of Japanese settlers.[3] The purpose of Furukawa's studies was to "penetrate the essence of the racial traits of the Taiwanese, who recently revolted and behaved so cruelly". Based on the finding that 41.2% of a Taiwanese sample had type O blood, he assumed that their rebelliousness was genetically determined. The reasoning was supported by the fact that among the Ainu, whose temperament was characterized as submissive, only 23.8% had type O. In conclusion, Furukawa suggested that the Taiwanese should intermarry more with the Japanese in order to reduce the number of individuals with type O blood.[3]

The craze faded in the 1930s as its unscientific basis became evident. It was revived in the 1970s with a book by Masahiko Nomi, a lawyer and broadcaster with no medical background. Nomi's work was largely uncontrolled and anecdotal, and the methodology of his conclusions is unclear.[4] Because of this he has been heavily assailed by the Japanese psychological community, although his books are phenomenally popular.[4]

Scientific research

While scientific study has shown that people of specific blood types may be more prone to certain illnesses, little research has been carried out on the correlation between blood type and personality traits. One such study, by the psychologist Raymond Cattell, examined blood samples of 323 Caucasian Australians for 17 genetic systems including 7 blood groups and 21 psychological variables.[5] The results produced 13 significant differences at a confidence interval of p<0.05 and 11 at p<0.01, the most conclusive finding occurring in the association between the P blood group system and anxiety.

Some medical studies show variation of hormones and enzymes which other studies have associated with personality changes: Individuals have varying levels of the enzyme dopamine beta hydroxylase and catecholamine hormones according to their blood type as a result of genetic linkage of nearby genes on chromosome 9 (the locus for ABO blood group in humans).[6] Congenital dopamine beta-hydroxylase deficiency is caused by mutation in the gene encoding dopamine beta-hydroxylase on chromosome 9q34, also the ABO locus.[7]

The ABO blood group system and platelet monoamine oxidase (MAO) activity are known to be two genetic markers for affective disorder. In researching a connection between the two markers, one study found that the platelet MAO activity of subjects with blood type O was significantly lower than that of subjects with other blood types,[8][9] criminal behaviour,[10] alcoholism, antisocial personality and impulsivity.[11]

Type A blood is the most common in Japan at about 40%,[1] and the proportion of blood type A is the largest in Hawaii, while type O is the most dominant in Bolivia, and type B is most common in Central Asia.[clarify]

Persons having Rh negative blood types are less common in the world population with a recent survey placing the percentage at around less than 20% of the total population, and no particular significance is attached to the Rh type.


Blood type theory is widely popular in women's magazines as a way to gauge relationship compatibility with a potential or current partner. Morning television shows feature blood type horoscopes, and similar horoscopes are published daily in newspapers. Though there is not a proven correlation between blood type and personality, it has still remained in the many matchmaking services that cater to blood type. In this way, it is similar to the use of astrological signs in the west, which is also popular in Japan. Asking about a blood type is common and it is often a surprise if a foreigner does not know his or her own blood type.

Many idols, tarento and other Japanese celebrities include a blood type statistic in their profiles, in addition to other facts as their hobbies and star sign.

It is common among anime and manga authors to mention their character's blood types, and to give their characters corresponding blood types to match their personalities. Some video game characters also have known blood types, such as in the Street Fighter series, Soul Calibur, and Dead or Alive, which lists character blood types in both the manual and in-game bios. In addition, it is common for videogame series, such as Gungriffon, Tekken, Animal Crossing and Princess Maker to allow for blood type as an option in their creation modes.

See also

  • My Boyfriend Is Type B A Korean romantic comedy based on the idea of blood type personality.
  • Blood type diet


  1. ^ a b c d Associated Press. "Myth about Japan blood types under attack", AOL Health, 2005-05-06. Retrieved on 2007-12-29. 
  2. ^ Landsteiner, K. (1900). "Zur Kenntnis der antifermentativen, lytischen und agglutinierenden Wirkungen des Blutserums und der Lymphe". Zentralblatt Bakteriologie 27: 357–62.
  3. ^ a b c Becker, Peter (Ed.); Yoji Nakatani (2006). "The Birth of Criminology in Modern Japan", Criminals and their Scientists: The History of Criminology in International Perspective (Publications of the German Historical Institute). Cambridge University Press, p. 294. ISBN 0521810124. 
  4. ^ a b D'Adamo, Dr. Peter J. (2002). The Eat Right for Your Type: Complete Blood Type Encyclopedia. Riverhead Trade, p. 28. ISBN 1573229202. 
  5. ^ "The relation of blood types to primary and secondary personality traits." The Mankind Quarterly, pp35-51, Vol. 21, 1980.
  6. ^ Goldin L, Gershon E, Lake C, et. al (1982). "Segregation and linkage studies of plasma dopamine-beta-hydroxylase (DBH), erythrocyte catechol-O-methyltransferase (COMT), and platelet monoamine oxidase (MAO): possible linkage between the ABO locus and a gene controlling DBH activity.". Am J Hum Genet 34 (2): 250-62. PMID 6951409.
  7. ^ Online 'Mendelian Inheritance in Man' (OMIM) 223360 "Linkage analysis by Wilson et al. (1987, 1988) yielded a lod score of 5.88 at a recombination fraction of 0.0 for the linkage of DBH and ABO."
  8. ^ Arató M, Bagdy G, Rihmer Z, Kulcsár Z (1983). "Reduced platelet MAO activity in healthy male students with blood group O.". Acta Psychiatr Scand 67 (2): 130-4. PMID 6573841.
  9. ^ Beitchman J, Mik H, Ehtesham S, Douglas L, Kennedy J (2004). "MAOA and persistent, pervasive childhood aggression.". Mol Psychiatry 9 (6): 546-7. doi:10.1038/ PMID 15024395.
  10. ^ Nilsson K, Sjöberg R, Damberg M, et. al (2006). "Role of monoamine oxidase A genotype and psychosocial factors in male adolescent criminal activity.". Biol Psychiatry 59 (2): 121-7. doi:10.1016/j.biopsych.2005.06.024. PMID 16125147.
  11. ^ Gutiérrez B, Arias B, Gastó C, Catalán R, Papiol S, Pintor L, Fañanás L (2004). "Association analysis between a functional polymorphism in the monoamine oxidase A gene promoter and severe mood disorders.". Psychiatr Genet 14 (4): 203-8. PMID 15564894.

Further reading

  • Toshitaka Nomi and Alexander Besher, You Are Your Blood Type: the biochemical key to unlocking the secrets of your personality. New York: Pocket Books, 1988. ISBN 0671633422
This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "Japanese_blood_type_theory_of_personality". A list of authors is available in Wikipedia.
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