In the 1930s, the Japanese embraced the idea of matching personality traits with one's blood type. This phenomenon is as popular in Japan as the idea of matching horoscope with personality is in America. Almost all Japanese are aware of their blood type.
Types & Meanings
While outwardly calm, they have such high standards (perfectionists) that they tend to be balls of nerves on the inside. Type A's are the most artistic of the blood groups. They can be shy, are conscientious, trustworthy, and sensitive.
Type AB's are the split personalities of the blood groups. They can be both outgoing and shy, confident and timid. While responsible, too much responsibility will cause a problem. They are trustworthy and like to help others.
Goal oriented and strong minded, type B's will start a task and continue it until completed, and completed well. Type B's are the individualists of the blood group categories and find their own way in life.
Outgoing, and very social. They are initiators, although they don't always finish what they start. Creative and popular, they love to be the center of attention and appear very self confident.
List of Celebrities Blood Types
It is interesting to note that a higher percentage of band members of the same band have the same blood type. This may be from self selection (That they find out blood types and choose members based off of this) or for some other underlying reason. For some reason most Hello! Project members have A type blood.