Blood type determinism in Japan

On the BBC, Ruth Evans describes a widespread Japanese superstition about the relationship between blood-types and personality. Apparently, the modern junk-science belief originates with a crank called Masahiko Nomi who published a "a book in the 1970s" about it, and his son Toshitaka has continued the family tradition with more woo books and an "Institute of Blood Type Humanics." However, Evans implies that the origin of this belief is the eugenics-grounded ideology of the Imperial militarist Japanese government of the 1930s, who "formed battle groups according to blood type."

It's apparently a very widespread belief. Employers ask prospective employees for their blood-types. Dating sites use blood-type to make matches. Blood-types form part of the plot in manga, anime and games. And big companies, sports teams, politicians and teachers are all known to discriminate based on typing:

The women's softball team that won gold for Japan at the Beijing Olympics is reported to have used blood type theories to customise training for each player. Some kindergartens have even adopted methods of teaching along blood group lines, and even major companies reportedly make decisions about assignments based on employees' blood types.

In 1990 the Asahi Daily newspaper reported that Mitsubishi Electronics had announced the creation of a team composed entirely of AB workers, thanks to "their ability to make plans".

These beliefs even affect politics. One former prime minister considered it important enough to reveal in his official profile that he's a type A, whilst his opposition rival was type B. Last year a minister, Ryu Matsumoto, was forced to resign after only a week in office, when a bad-tempered encounter with local officials was televised. In his resignation speech he blamed his failings on the fact that he was blood type B.

Not everyone sees the blood type craze as simply harmless fun.

It sometimes manifests itself as prejudice and discrimination, and it seems this is so common, the Japanese now have a term for it - bura-hara, meaning blood-type harassment. There are reports of discrimination against type B and AB groups leading to children being bullied, the ending of happy relationships, and loss of job opportunities.

Japan and blood types: Does it determine personality?


  1. I’ve been living here for 20 years and for the past 15, when inevitably asked about my type, when out drinking with colleagues or new acquaintances, I answer, “I don’t know”. And then I try to change the subject. (Get off my lawn! grumble, grumble.)

      1. Oh, it’s real-academic, but very bad science. Has pretty much the same reputation as evo-psyche does in certain circles, actualy…

  2. It’s like a cargo cult: some bit of new technology arrives (like blood typing) and everyone is so awed by it that it becomes something to worship.  Right now, some culture is probably starting to fetishize DNA SNPs in the same way.

  3. I have the same blood type as Hello Kitty. It’s been three years since I found that out, but I still don’t know to come to terms with the knowledge.

  4. Grouping battle groups by blood type would have one advantage in that anyone injured in those units could receive a blood transfusion from any of the others.

    1.  Excellent point – if someone is carried in to a medical station, 95% of the time you wouldn’t have to look further for a blood donor than the people carrying him.

  5. I always wondered if it really works, though it might in a relatively homogenous population. Regardless the Japanese love to ask about your personality type, which is conveniently a “blood type”, i.e. A is logical B is emotional/laid back, AB is trickstery, O is generous or whatever. Makes me think maybe there could be general personality types, or at least general outlooks for certain personality facets, that you could use in conversation regardless of what the blood type actually is. That said this is not news, it’s been popular for quite a while. Someone must have done some actual studies?

    1. I wonder if the type O negatives’ supposed generosity is inspired by they fact that they’re universal donors.

  6. It’s definitely a very common belief. During my two trips to Japan (a year and a half total) I had all kinds of people ask me my blood type. When I told them I didn’t know, they were utterly shocked. I think it’s probably even more common knowledge over there than the idea of zodiac signs in the US. Obviously it’s a lot more far-reaching, though, if it affects politics.

  7. I’ve known some otherwise very intelligent Russian scientists that were convinced of this very same notion.  They called me “typical ignorant meer-ikan” when i asked (quite innocently) if that meant there were only four personality types.   somewhere someone has already compiled curious convictions by country, i’m sure..?

  8. Here in America, we know that blood types can’t possibly have any influence on the way the body or brain works, that’s just a foolish superstition.    If you want to know infallibly what a person’s character contains, you must use the Meyers-Briggs personality profile!

    1. Myers-Briggs does tell you something about someone: how they answer questions that show up on a Myers-Briggs test. It might be a poor look at personality, but at least you’re facing towards it.

      In contrast, blood antigens are a much more accurate and scientific description of something that isn’t even in the same room. You might as well go with birthdays or something.

      1. “It might be a poor look at personality, but at least you’re facing towards it.
        In contrast, blood antigens are a much more accurate and scientific description of something that isn’t even in the same room”It’s not anything of a contrast. People read into both whatever they wish to.

        1. Huh? One is a grouping of symptoms. It may not be the best tool, but it is actually an analysis system for grouping actual symptoms.

          The other is random data from a completely unrelated area. 

          If I use a set of symptoms to try to trap an error in code that might not be the SOLUTION but it might bring us closer to finding something to solve the error.

          Using blood type would be like throwing a dart at it and then saying “that’s it!!! Change that!”

          1. As long as you’re categorising the blood type superstitions as “actual symptoms” and the Meyers-Briggs nonsense as “completely unrelated random data” I’ll agree with you!  ^_^

            Should physicians ignore blood type when giving transfusions?  If, as you imply, there’s absolutely no difference between blood types, then that should be no problem.  If there is a difference, I don’t think anyone here has proved that personality is not influenced by it (not endorsing any such interpretations or superstitions here, just pointing out facts).

            Blood type has known physical reality.  I don’t know what the physical expression of all that reality is limited to – but I know it’s real, and can be measured and tested, and can’t be gamed by studying the test questions or pretending to be somebody else.  Meyers-Briggs is a bunch of horse puckey by comparison.

            I think the problem here is you might think I’m endorsing these Japanese superstitions about blood type.  I’m not.  I’m saying entirely dismissing the idea that blood type could have effects on the organism at the level of personality is unwise; just like relying on Meyers-Briggs is unwise.  I think truly studying the relationship between blood type and emotions would be interesting.

  9. Yes, this fascination is real, and yes, it is widespread. To the point that I did indeed notice it was almost scientific fact there. People asked me my type a few times, and I told them I wasn’t sure too, because I wasn’t!

    And yes, as far as I know, it’s because of one lone quack in the 1970s having wrote a book on it. And in Japan, all a cultural superstition takes to form is one person writing an inflammatory popular book about something that takes hold of public consciousness long enough for people to remember. Not whether it was true or not, people there seem to assume from what I saw that by publishing, the information was somehow deemed true by a publisher.

    There are countless diet fad books that can attest to this, like the infamous konyaku diet fad that NEVER GOES AWAY. No matter how many people debunk it.

    The more superstitious and religion oriented a culture (and Japan is both extremely superstitious and highly religion oriented by life ceremonies, such as boys days, funerals, birth ceremonies, setsubun, the list goes looooong on), the more I have noticed a tendency for some portion of the population, much like flat-earthers in the west, to always ignore actual scientific debunking and stick to an insane belief.

    It’s almost as though a mass-recognized ignorance at one point somehow inoculates a permanent living part of a population against the scientific opposing view of it. Calling their belief factually untrue actually strengthens their acceptance of their original stupidity, much like a disease.

    Perhaps this is why religion exists in the modern age.

    1. When you say it’s like they think the publisher verified that the information in the book is true, you hit the nail on the head.  Japanese people in general are very trusting of their authority figures.  If something makes it into the news or if an official says something or it’s published in a book they immediately believe it.  It’s amazing to me how every time there’s some kind of scandal, they’re all just totally stunned, as if this had never happened before.  Of course we have people who are overly credulous here, too, but it’s a bit different.  Cultural differences in how credulity works!  Cool stuff!

      1. Over here in the USA we have people who honestly believe that lowering taxes stimulates the economy and that increasing the penalties for crimes decreases the amount of crime.  No matter how many times these fallacies are exhaustively disproved, any politician or preacher can still find an audience willing to believe.

    2. I see it as a totem of group membership.  There’s simply little benefit in contradicting one’s friends, so objectivity takes a secondary role.  Unfortunately a lot of East Asian “education” is along these lines.

  10. I think this is a fantastic idea, and we should have more of it.

    In the west, none of us know this important info – none of us can give it to the paramedics when they pick us up, unless maybe we’ve given blood and remember what they stamped our card with.

    In Japan, even people’s *friends* know what type they are! Even if you’re unconscious, people will know this.

    What other emergency info can we make silly fortune telling nonsenses out of, so people remember them?

  11. “Some kindergartens have even adopted methods of teaching along blood group lines”

    I am comforted that there is one level of superstitious idiocy to which America has not yet sunk– Tailoring education to one’s horoscope.

    Oh shit, this article just gave some hippie with an early-education degree an idea.

    1. Don’t worry. They don’t let hippies teach in some places. In our state, the important thing is to recognized that critical thinking is NOT an education goal, and counters authority.

      You think they hire hippies?

  12. If I was asked my bloodtype in Japan, I’d be tempted to play with it.  After all, if they believe in ONE irrational thing…

    “What’s your bloodtype?”
    “Oh, I’m type Q-sidereal.”
    “Yes, it’s new.  We’re the next stage of human evolution, destined for greatness.  But don’t worry, we’ll be compassionate rulers.  Your lives, such as they are, will go on more or less as they do now.”

  13. But the thing is, it doesn’t seem particularly impossible for this belief to have some truth to it (unlike say homeopathy or perpetual motion, either of which is inconsistent with generally accepted laws). The history of the belief should make us very skeptical – but it wouldn’t be any weirder than having eye color and some aspects of personality correlated, which appears to actually be the case (see Kagan’s work on shyness and blue eyes). Personally I’d wait for a study before just dismissing this stuff out of hand.

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