Blood Type Personality Theory

The Blood Type Personality Theory (血液型性格分類, Ketsueki-gata Seikaku Bunrui) is a pseudoscience with highly controversial origins, claiming that blood type can predict one's compatibility and personality. Historically, it was popular in Japan and South Korea.

History

As nationalist propaganda

The ABO blood types were first discovered by Karl Landsteiner in 1901, then further research was done by Emil von Dungern and Ludwik Hirszfeld on heritability. During this time period, scientific racism was popular,¹⁾ so the Eugenicists obsessed with racial purity attempted to warp the research to fit their future slogans of blood and soil, asserting that certain types were 'move evolved' than others.²⁾³⁾

In 1916, Kimata Hara, a Japanese doctor that studied under Durgen, brought their research to Imperial Japan and he briefly touched on linking blood types to personality.⁴⁾ This was taken seriously by the military around 1926,⁵⁾ eventually leading up to Takeji Furukawa publishing his paper in 1927 that would formally link blood types to personalities, enabling their military to discriminate by blood type.

As a personality theory

Following the events of World War II, such theories were left alone until people got the idea to simply 'remove' the theory's racial aspects, turning it into a personality diagnosis test. It was known that Léone Bourdel had published an academic paper in 1962,⁶⁾ but it wasn't really popular until Masahiko Nomi published a book in 1971, which somehow became a bestseller in East Asian countries like Japan and South Korea.

Soon enough, it became a cultural phenomenon which influenced media, television segments, and became a factoid that people really wanted to know about their favorite celebrities or fictional characters. However, the psychologists would quickly discover that the reformed theory made people uncomfortable, as the whole thing could still create discriminatory assumptions of others despite the change.⁷⁾

However, it took decades until their theory started being phased out in the 2000s. Japan eventually shelved it after the Broadcasting Ethics & Program Improvement Organization deemed it a 'social issue' in 2004,⁸⁾ then South Korea saw the Korean Society of Hematology formally reject it in 2008.⁹⁾¹⁰⁾ Of course, some might still believe in it to this date, but please keep in mind that its dark history isn't common knowledge.

Assessments

There doesn't seem to be a major, overarching definition of the four blood type personalities, possibly to be ambiguous, so I've organized what's been said about them from various sources:

Source	Type O	Type A	Type B	Type AB
Dong-A Ilbo (1937)¹¹⁾	• Polite, proud. • Not easily swayed.	• Careful, cautious. • Very emotional.	• Sociable, witty. • Doesn't hold grudges.
Sang et Tempéraments by Léone Bourdel (1962)	• Eccentric, romantic. • Fine with change. • Skilled in diplomacy.	• Compliant, sincere. • Mostly reserved. • Unlikely to take risks.	• Active, passionate. • Emotional lover. • Athlete. Leadership.	• Delicate, nervous. • Easygoing, but cold. • Hard to figure out.
血液型でわかる相性(Ketsueki-gata de Wakaru Aishou) by Masahiko Nomi (1971)	• 'The Boss' • Prone to a hierarchy. • Values connections.	• 'The Leader' • Relies on framework. • Values connections.	• 'The Director' • Technically inclined. • Facts over people.	• 'The Pillar' • Strongest presence. • Gets things done.
The Guardian (2008)¹²⁾	• Decisive, curious.	• Reserved, sensitive.	• Cheerful, flamboyant. • 'Free thinking'.	• Artful, distant. • High maintenance.
The Guardian (2008)¹²⁾	• Elizabeth II. • Elvis Presley.	• Adolf Hitler. • Britney Spears.	• Jack Nicholson.	• Mao Zedong.
Courrier Int'l (2019)¹³⁾	• Born leaders. • Very enthusiastic.	• Kind, polite, sweet. • Organized.	• Passionate creatives. • Rebellious.	• Eccentric, contradicts. • Very understanding.
Courrier Int'l (2019)¹³⁾	• Politicians.	• Accountants. • Mediators.	• Self-employed. • Musicians. • Journalists.	• Teachers. • Lawyers. • Social workers.

As for the four stereotypes: Type A is timid, Type B is stingy and psychotic, Type AB is eccentric or lazy, and Type O has the least negatives which makes them a target for the other three blood types.

Notes

I want to be clear that, in case the message somehow became lost, Eugenics is a bad thing.
The truth about blood types is that blood type distribution is essentially random. You can see that Ecuador and Peru has a lot of Type O blood, but it doesn't affect their military personnel.
Recently, the theory has kinda declined in favor of alternatives, like that Myers-Briggs Type Indicator.
For those curious, the curator has Type AB+ blood. I have not donated plasma yet.

External links

Blood type personality theory on Wikipedia
Blood type divination on Pixiv Encyclopedia [JA]
Blood type on Niconico Encyclopedia [JA]
Blood type personality theory on Namu Wiki [KO]¹⁴⁾

¹⁾

"Bad blood. Blood-group research and the serologist Ludwik Hirszfeld in Germany and Poland". Jahrbuch historie.

²⁾

"How a Bizarre Obsession Advanced Science" (May 31, 2013). Spiegel.

³⁾ , ¹⁰⁾

"You're type AB, right? (Studio K) | KBS WORLD TV 200910" [2:54] (September 10, 2020). YouTube.

⁴⁾

“Regarding the Genus Structure of Blood” (血液ノ類属的構造ニ就テ), authored by “Kimata Hara” (原來復) and “Sakae Kobayashi” (小林栄), published in “Iji Shunbun, No. 954” (『醫事新聞』第954号).

⁵⁾

“Regarding Human Blood Agglutination Reaction” (人血球凝集反応ニ就テ), authored by “Hayashi Hirano” (平野林) and “Tomita Yajima” (矢島登美太), published in “Gun'i-dan Zasshi, No. 157” (『軍医団雑誌』157号).

⁶⁾

“Léone Bourdel” was a French psychologist who wrote an academic paper in 1962 that was titled “Blood and Temperaments” (Sang et Tempéraments).

⁷⁾ , ⁸⁾

"「血液型を扱う番組」に対する要望" (December 8, 2004). Broadcasting Ethics & Program Improvement Organization.

⁹⁾

"혈액형이 성격 결정? ‘새빨간 거짓말’" (May 26, 2008). The Hankyoreh.

¹¹⁾

"혈액형에 따라 성질판단법" (September 16, 1937). The Dong-A Ilbo.

¹²⁾

"Typecast - Japan's obsession with blood groups" (December 3, 2008). The Guardian.

¹³⁾

"L’obsession des Japonais pour les groupes sanguins" (December 19, 2019). Courrier International.

¹⁴⁾

In the Namu Wiki article, there's a clip of a scene in the 2006 film, My Scary Girl, where the protagonist angrily denounces the personality theory, noting that only Japan and South Korea still believes in it.

Nameless Rumia's Wiki

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