Ask a Korean their blood type and you might get a personality reading instead of a medical fact. Type A is careful, type B is selfish, type O is a leader — an entire folk psychology, taken semi-seriously by millions. We trace where the idea actually came from, why it stuck across Korea and Japan, how it shows up in dating and dramas, and what the science says (spoiler: not much).

— Hosted by Jacob Lee. Independent production. All facts drawn from publicly available sources.