The Japanese are obsessed with the belief that people's blood types are the windows to their personalities, the U.K.'s Telegraph reports.

The obsession is evidenced by the four books analyzing blood types that have dominated the country's Top 10 best seller list for the past year, according to the report.

The blood type-personality theory emerged in Japan in 1927, but didn’t take off until the 1970s when the first of 30 books on the subject was published.

Despite a lack of scientific evidence proving a link between blood type and temperament, everything from matchmaking services to cosmetic companies have successfully marketed the theory to the country’s masses.

From reserved perfectionists Type As and confidently curious Type Os to high maintenance Type ABs, there are products and services to suit every blood type, the Telegraph reports.

Know Your Blood Type, Know Yourself

TYPE A – Patient, uptight, sensitive, responsible, cautious

Famous examples: Adolf Hitler, Britney Spears, Ringo Starr

TYPE B – Individual, unconventional, optimistic, unpredictable, creative, strong

Famous examples: Paul McCartney, Jack Nicholson, Leonardo Di Caprio

Click here for more on this story and to find out what your blood type says about your personality.