Born in the Northern Song region, Xu Zi Ping (徐子平), originally named Ju Yi (居易), was an accomplished astronomer well-versed in reading star signs and authoring many divinatory discourse books. Xu Zi Ping based his study of the Four Pillars of Fate calculations on “Li Xuzhong’s Book of Fate”《李虚中命书》. He developed his complete version of the Four Pillars of Fate system and wrote “Vastness of Zi Ping”《渊海子平》. The primary difference between the two Four Pillars of Fate calculation systems is their focus. Li Xuzhong emphasised the year’s Heavenly Stems and Earthly Branches (HsEb) as the main focus of a person’s fate, with the month and day HsEb as supporting elements. In contrast, Xu Zi Ping’s theory and system placed the person’s Day Master (HsEb) at the centre of Fate and character analysis, with the other three pillars’ HsEb combination serving as supporting elements. He renamed the Four Pillars of HsEb to “Eight Characters” (八字), a term that remains commonly used for the calculation system today. The book “Vastness of Zi Ping”《渊海子平》significantly contributed to the development of Chinese Metaphysics during the Northern Song Dynasty period. Many translated and illustrated copies of this title have been widely circulated among practitioners and enthusiasts alike.