Eight-character astrology began in the Tang Dynasty, with Nianzhu as the main body, life as the life, supplemented by Yinna method. In the Tang Dynasty, Li changed it to year-based and used four pillars: year, month, day and hour. In the Five Dynasties, Xu Ziping changed to Japanese occupation as my (Japanese master), focusing on the restraint of the five elements between the four pillars and the encounter between punishment and punishment, and carried it forward. Today's eight-character divination is based on Ziping method, so the eight-character numerology is also called Ziping method or Ziping eight-character study.
The "eight characters" are also called four pillars (year pillar, moon pillar, sun pillar and time pillar), each of which has two characters, above which are heavenly stems (A, B, C, D, E, Ji, Ke, Xin, Man and Ghost) and below which are earthly branches (Zi, Ugly, Yin, Mao, Chen, Si and Wu).