The Huangji jingshi is an attempt to give history a mathematical shape. Shao Yong divides time by twelves and thirties in the way a calendar divides a day, and continues the division upward past the year until he arrives at a complete world cycle: one yuan of 129,600 years, made of twelve hui, each of thirty yun, each of twelve shi. Within that cycle a world comes into being, flourishes, declines and ends, and the sequence of dynasties can be located on it.
The machinery of the system is a repeated fourfold division taken from the Yijing. Heaven has four images, sun, moon, stars and zodiacal spaces; earth has water, fire, soil and stone; a person has ear, eye, nose and mouth; there are four kinds of ruler, four kinds of government, four ways a thing can be affected. Everything is generated by doubling: two into four, four into eight, and so on to sixty-four and beyond. Shao Yong claimed to be recovering the method by which the sages made the hexagrams rather than inventing a scheme of his own.
What he wanted from it was a way of seeing things as they are rather than as the observer wishes them to be, which he called viewing things from the standpoint of things. The numbers are a discipline of detachment as much as a description of the cosmos, which is why contemporaries who thought the calculations eccentric could still regard him as an exemplary man.