While for most westerners it’s not uncommon to have no idea what their own blood type is, in Japan almost everyone knows theirs. Japanese Wikipedia includes blood type when listing information on celebrities, as well as social networking sites like Facebook allowing blood type to be displayed on user profile’s for many Asian countries. I’ve even played video games where they make you pick blood type.
It is believed that you can find out a lot about a person’s character or who they might be compatible with, just based on which type they have. There are even diets and exercises designed around them. Blood type is a subject that will come up in conversation in Japanese from time to time, and is usually a surprise when heard foreigners don’t know their own type.
Blood type A (Ａ型) is thought to be the conservative type. They are reserved, have a tendency towards perfectionism, are composed, and lead introverted lifestyles. They can be a bit self-conscious and obsessive, and tend to keep to themselves, yet are still considerate to others and are faithful.
Blood type B (Ｂ型) is creative, easy-going, adaptable and independent. They can sometimes be careless and absentminded however. They like meeting new people and becoming friends with people that may have different interests.
Blood type AB (ＡＢ型) think logically, are calm and reasonable. Even though they tend to think logically, they can be uncertain about things at times and do not easily forgive others. They are appealing and are well-liked by their peers. They do not like to nit-pick, dislike being restricted and are controlled by their brain rather than their heart.
Blood type O (Ｏ型) have driving, boisterous personalities. They may be perceived as high and mighty, callous and big-headed. They are thought to be born leaders, energetic and amorous. They are eager and willing, and are not afraid of taking risks to get what they want.
Although it seems like something fun and innocent, some people claim to be judged solely on their blood type. It’s not unheard of for an employer to ask a prospective employee what their blood type is! There’s even a word for blood type harassment: “ブラハラ”.