Blood Type Personality

This custom is said to have started in 1916 when some doctors in Japan made a medical report stating that people with Type A Blood were generally mild-tempered and intellectual, while people with Type B Blood were just the opposite. Today in Japan, blood type is popularly used as a personality-type indicator. Even though it hasn't been proven to have any scientific basis, many Japanese people believe in these distinctions to one degree or another.

Type A
Speaking broadly, it is said that people with Type A Blood are calm, composed, and very level-headed and serious. They have a firm character, and are reliable and trustworthy (and hardheaded). They think things over and make plans deliberately, and they plug away at things steadily and assiduously. They try to make themselves more like their own ideal of what they should be. A Types may look aloof or distant to others. They try to suppress their own emotions, and because they have continual practice in doing this, this makes them appear strong. But, actually, they have a fragile, nervous side, as well. They tend to be hard on people who are not of the same type, and so they consequently tend to be surrounded with people of the same temperament.

Type B
People with Type B Blood are curious about and interested in everything. That's may be good, but they also tend to have too many interests and hobbies, and they tend to get all excited about something suddenly and then later drop it again just as quickly. But they do manage to know which of their many interests or loved ones are the ones that are really important, the ones they should hold on to. B Types tend to excel in things rather than just be average. But they tend to be so involved in their own world or become so carried away with something that they neglect other things. They have the image of being bright and cheerful, full of energy and enthusiasm, but some people think that they are really quite different on the inside. And it can also be said about them that they don't really want to have much real contact with others.

Type O
Type O Blood people are said to set the mood for a group and to take on the role of creating harmony among its members. Their image is one of taking it easy, of being peaceful and carefree. They are also thought to be big-hearted and benevolent, and they tend to spend money on others generously. O Types are generally "loved by all." But, they also, surprisingly, have a stubborn and strong-willed side, as well, and tend to secretly have their own opinions on things. On the other hand, they have the flexible, adaptable side of readily accepting new things. They are easily influenced by other people or by what they see on TV. They seem to appear level-headed and trustworthy, but they often slip and make big blunders inadvertently. But that is also the point that makes O Types lovable.

Type AB
People with Type AB Blood are said to have a delicate sensitivity. They are considerate of other people's feelings and deal with them with care and caution. On the other hand, though, they are strict with themselves and those close to them. They, therefore, seem to have two personalities: one for those "outside," and another for people on the "inside." They often become sentimental, and they tend to think too deeply about things. AB Types have a lot of friends, but they need time to be alone and think things through, as well.


Blood Type A is the most common Japanese blood type. In America, Blood Type O is by far the most prevalent. In Japan, schools carry out thorough physical exams, and so the majority of Japanese people find out their own blood types from the results of these exams. Many Japanese are amazed to learn that a large number of Americans don't know their own blood types. "What's your blood type?" is a question heard much more frequently in Japan than, say, "What's your zodiac sign?" is heard in America. It is sometimes even used in casual self-introductions in informal situations.
The internationally-adored Japanese cartoon Sailor Moon, by Naoko Takeuchi, mentions the blood types of her characters several times throughout the series. Blood type is considered an important enough characteristic in Japan for Ms. Takeuchi to give the blood types of each of her characters in their profiles. For example, in one such introduction of her characters, she includes "name," "birthday," "zodiac sign," "blood type," "age," and "school name," in that order. And sure enough, the personalities of her characters conform to a large degree to these blood-type stereotypes.


Sailor Moon Character's Blood Types
Type A
Ami (Amy)
Mamoru (Darien)
Setsuna (Sailor Pluto)

Type B
Minako (Mina)
Haruka (Sailor Uranus)

Type O
Usagi (Serena)
Chibi Usa (Rini)
Makoto (Lita)
Michiru (Sailor Neptune)

Type AB
Rei (Raye)
Hotaru (Sailor Saturn)