From a Western point of view, the experience may happen to be funny: ask anyone in Japan if they knows his blood type, and in the large majority, they will answer positively. While Europeans are often only one third to know their blood type, Japanese people (just like South Koreans and Taiwanese people) value this information a lot.
To the point that after asking your nationality and age, Japanese people will often ask you about your blood type in order to know more about you. According to a strong popular belief, this/these small letter/s may have a real link with somebody’s temperament. Interesting to be noticed: the animal linked to the birth year has little to none impact in Japan.
While the truth still has to be proven by a serious scientific study, this link becomes a must-know during these past forty years. Therefore, it is not surprising that presentation sheets of manga/videogame characters include this element. Same trend for the athletes, idols and other TV celebrities who show it, more or less with pride, in their facts sheet.
A strong and sometimes overwhelming presence
But the blood type can impact much more than this, since marketers use it with no shame to sell personalized items to each types, especially in food, drink and diet industries. The horoscope is also delivered according to the blood type and not based on the zodiac sign. Regarding the matrimonial agencies and dating websites in Japan, they also use the concept to insure their probabilities of compatibility.
Even job interviews can be influenced, which leads some people to lie about their type! And another dark side of it, some school harassment (called ijime) exists due to the blood type. In Japan, we can count about 38% of A type, 30% of B type, 22% of B type and 10% of AB type. The positive or negative rhesus does not matter since it only concerns about 1% of the Japanese population.
We can explain this obsession by several successive Japanese writers:
- Doctor Kimata Hara wrote as early as 1916 (so about 15 years after Austrian biologist Karl Landsteiner discovered them) a paper about the link between personality and blood type;
- Takeji Furukawa published in 1927 the results from a research made about the temperament through blood types, a study which will be used by the Japanese army until a little before the Second World War;
- and the journalist Masahiko Nomi edited in 1971 a book which revived the trend and delimited the basics of this strong interest.
Temperament traits and types’ personality
Here are the main traits for each blood type.
A people would be serious, honest, quiet and responsible, gentle and reserved, punctual, patient, clean and looking for perfection, attentive to details with a bit of creativity (and apparently good drivers!).
However they are said to be cautious, sensitive, stubborn, picky and anxious.
B people would be free-spirited, creative, passionate and optimistic, voluntary, playful, flexible, enthusiastic and enterprising.
However they can be rebellious, distracted, unpredictable, impulsive, reckless, resentful and selfish.
The rare AB would be relaxed, sociable and compassionate, organized, rational and easily adaptable.
However they can be cold, critical, dizzy, undecided, ruthless and hard to understand.
Finally, O would be ambitious and passionate, natural leaders who have self-confidence, independent, carefree and following their intuition.
On the contrary, they can be arrogant, cold and suspicious, somehow jealous and insensitive and even workaholic!
In Japanese language, blood type is called 血液型 ketsuekigata and a "A type" would be A型 (gata).
Picture is from the anime Ketsuekigata-kun, aired in 2013 on Japanese TV