03/04/2026
Did you know the Japanese use blood type to ascertain our psychological profile called The Japanese ketsueki-gata (血液型) personality theory originated in the 20th Century.
The first Dr was in 1916 Dr Kimata Hara who published early research suggesting a link between blood groups and temperament.
Furukawa's (in 1927) Inspiration who was a Psychologist who published "Ketsuekigata ni yoru Kish*tsu no Kenkyū" ("The Study of Temperament Through Blood Type"), formally introducing the theory to the public.
Furukawa drew from Hippocrates' ancient Greek humoral theory, which classified temperaments (sanguine, phlegmatic, choleric, melancholic) based on bodily fluids.
He proposed blood type could objectively replace the four humors for studying temperament, merging physiological and psychological dimensions .
The 1970s RevivalThe theory died out after Furukawa's death but was revived in the 1970s by:Masahiko Nomi – A journalist with no medical background who published bestselling books on blood type and personality
Tosh*taka Nomi (his son) – Continued promoting the theory and established the Institute of Blood Type Humanics:
Why It Stuck : Nomi's books became self-help guides for romance and business, transforming ketsueki-gata into a cultural phenomenon despite lacking scientific evidence.
Today it influences dating, hiring, and consumer products across Japan, Korea, and Taiwan
Note: Furukawa's original research was criticized for small sample sizes and lack of empirical evidence, and modern studies confirm no credible link between blood type and personality
