Zi Wei Do Shu or the Purple Star Astrology is an interesting branch of Chinese astrology based on the Chinese Lunar Calendar. Purple Star Astrology is based on Chinese Astrology that predicts a person's overall personality as well as his potential throughout his life related to money, profession, asset, health and relationship with parent, siblings, spouse, children and friends, the 12 palaces of life. All calculations are done based on a person's date of birth. The origin of Purple Star Astrology can be traced back to 980 - 1280 A.D i.e. during the Sung dynasty and is mainly attributed to Chen Hsi Ee, who is known to have improved, refined and documented this entire system of Chinese Astrology. There are over then 100 stars in the Zi Wei Do Shu system out of which only 30 or 40 of them are considered to be important for the purpose of conducting an accurate reading.