The discovery of blood types in 1901 has been hailed as one of the greatest advances in medical history, but the breakthrough was then used by the Nazis to further their eugenics program, and claim the superiority of Germans -- mostly types A and O -- over Jews, Asians and others with a larger proportion of type B blood.
According to Nomi's theory, those with type A blood tend to be reserved, punctual and law-abiding while type Os tend to be more outgoing and individualistic. Type A blood is the most common in Japan and Germany while type O is most prevalent in the United States. Interestingly enough, 60 percent of Japanese Prime Ministers have been type O. Type Bs also tend to make great cooks and restaurant guides featuring Type B chefs are popular products in Japan.
In Japan AB blood type is often considered the least desirable type.
Persons having Rh negative blood types are extremely rare in the Japanese population, and generally the Japanese attach no particular significance to the Rh type.
In Nazi Germany research was done to associate B-type blood type with inferior personal characteristics. B-type blood was relatively common among German Jewish populations. This research has since been discredited.