In ancient times, people's birth time was expressed by four branches of year, month and day, each with one word, a total of eight words, commonly known as birth or eight characters or four pillars. It can be seen that the eight characters are also a way to express birth information.
Four-pillar prediction is a branch of information prediction science developed on the basis of Zhouyi. The Eight Diagrams of Zhouyi is the study of people or things, and the four pillars are the study of people's fixed information.
Birthday, or eight characters, is actually another way of saying the four pillars of Zhouyi. Four pillars refer to the time when a person was born, that is, year, month, day and hour. When people use "heavenly stem" and "earthly branch" to represent year, month, day and hour respectively, such as Jiazi Year, Shen Bingyue, Xin Ugly Day and Renyin Time. There are two words in each column and eight characters in four columns, so fortune telling is also called "measuring eight characters" According to the relationship between yin and yang attributes and the five elements of heaven and earth, it is inferred that human body is responsible and blessed.