the chronological column, that is, the year when a person was born, is represented by the trunk and branch of the solar calendar, that is, the trunk and branch chronology. The annual column update is based on the annual beginning of spring. : The four pillars and eight characters are all based on the solar terms, and do not refer to any lunar calendar content. The dry calendar belongs to the solar calendar. Take beginning of spring as the first year.
The chronology of Ganzhi dates back to Fu Xishi, the first of the three emperors and five emperors in China. Fu Xishi divided the year into December, and the chronology of Ganzhi dates back to now.