Each blood type waged a difficult, and very distinct, battle for its existence some far time ago. The driven loner Type 0 would have failed miserably in the orderly, cooperative environment of Type A--a big reason for the blood type adaptation in the first place. Would it be such a surprise to find many of these primitive characteristics hidden in some deep remove of our psyches?
The belief that personality is determined by one's blood type is held in high regard in Japan.
Termed ketsu-eki-gata, Japanese blood type analysis is serious business. Corporate managers use it to hire workers, market researchers use it to predict buying habits, and most people use it to choose friends, romantic partners, and lifetime mates. Vending machines that offer on-the-spot blood type analysis are widespread in train stations, department stores, restaurants, and other public places. There is even a highly respected organization, the ABO Society, dedicated to helping individuals and organizations make the right decisions, consistent with blood type.
The leading proponent of the blood type-personality connection is a man named Toshitaka Nomi, whose father first pioneered the theory. In 1980, Nomi and Alexander Besher wrote a book called You Are Your Blood Type, which has sold more than 6 million copies in Japan. It contains personality profiles and suggestions for the various blood types--right down to what you should do for a living, whom you should marry, and the dire consequences that might befall you if you should ignore this advice.
It makes fun reading--not unlike astrology, numerology or other methods of finding your place in the uncertain scheme of things. However, most of the advice in the book should be taken with a grain of salt.
So what is the value of this speculation, and why are we including it here?
It's very simple. Although the Japanese ketsu-eki-gata may be extreme, you can't deny that there is probably an essential truth to the theories about a relationship between our cells and our personalities. Modern scientists and doctors have clearly acknowledged the existence of a biological mind-body connection.
The idea that your blood type may relate to your personality is not really so strange. Indeed, if you look at each of the blood types, you can see a distinct personality emerging--the inheritance of our ancestral strengths. By playing to your blood type's strengths, you may be able to achieve greater efficiency and accuracy in your work, and greater emotional happiness and security in your life.
Source: Peter J. D'Adamo: Eat Right 4 Your Type: The Individualized Diet Solution to Staying Healthy, Living Longer & Achieving Your Ideal Weight