Jinkouyu is also known as "Sun Hao Predictives", also known as "Sleeve Gold" and "Da Jinkou". Jinkouyu is a high-level forecasting developed from the Big Six, which combines the best of Taiyi, Qimen and Liuyi. Because the computing system of the Big Six is ​​more complicated, it consists of heaven and earth, four lessons, three passes, and gods. It is difficult for ordinary people to learn. During the Warring States period, Sun Yanshi learned from Yi Guiguzi and simplified the Big Six into four