Sasang typology

The Sasang typology (Hangul: 사상의학. Hanja: 四象醫學) is a traditional Korean medical typology, which was systematically theorized by Lee, Je-ma and his book, "Longevity and Life Preservation in Eastern Medicine" (東醫壽世保元, 동의수세보원) in 1894. This medical typology divides people in four types based on their biopsychosocial traits; Tae-Yang(Greater Yang), So-Yang(Lesser Yang), Tae-Eum(Greater Yin) and So-Eum(Lesser Yin) types.

This is based on absolutely no evidence what so ever except for the fact that it was written in some book hundreds of years ago. Even Korean Traditional practitioners can not concur as to what Yin a person is, this can be shown by going to a different Korean Traditional probationers and asking them which will lead to a different answer each time.