It is a type of Chinese arithmetic. Generally speaking, there is a process called "testing the time of the iron plate divine number". According to those who are involved in the iron plate divine number, that is because the time provided by the customer is only an approximate time, not the real birth time. The industry needs to calculate the customer's birth time to a precision of eight quarters in an hour and fifteen minutes in a quarter in order to achieve the most accurate inference. The iron plate maker will type out some terms and then ask the customer if they are correct. After a round of verification and the completion of the "examination time setting" process, the iron plate manufacturers will begin to type out other provisions, which generally include provisions on the situation of six relatives and different ages. After all the articles are arranged and sorted, they become an iron-clad destiny book of divine numbers.
It was previously thought to be written by Shao Kangjie of the Song Dynasty, but there is still no conclusive evidence. In the Qing Dynasty, a Taoist priest named Tiebuzi used a divine number to calculate people's names. His technique was very popular at the time. It became popular for a while, and everyone flocked to it, and it immediately became a very famous but mysterious spell. The "iron version" in the iron version of the divine number means the "iron version" of the magical number.