This is the first book in any language that attempts to make an academic study of three sophisticated devices known as sanshi, used in the Chinese astronomical bureau in the 11th century.

Though there are a number of well-written works on Chinese divination, there are none that deal with the three sophisticated devices that were employed by the Chinese Astronomical Bureau in the eleventh century and for hundreds of years thereafter. Chinese experts applied the methods associated with these devices to both weather forecasting and to the interpretation of human affairs.