The 72 Dragons and the 120 Gold Nuggets are two rings and calculations widely used in classic San He Yin Zhai Feng-Shui. These two rings are present in almost all the designs of the oldest Luo-Pans. The 72 Dragons ring is attributed to the great Yang Yung Sun of the Tang dynasty. In this ring we divided the circle into 72 angles of 5º each. Each of these angles corresponds to on of the sixty pillars. Pillars are combinations of heavenly stems and earthly branches.
As there are 60 pillars in total, there are 12 dragons without a pillar. Such angles/directions are called “Empty Dragons”. To each dragon we associate the concept “inner sound”, which is an image and element of corresponding pillar. Each of the 72 dragons also has a "pulse". There are five sequential pulses which are: Cold - Pure - Failure - Strong - Failure. The empty Dragons have no pulse. The best pulses are Pure and Strong.
In the 120 gold nuggets, as the name implies, we divide the circle into 120 angles or intervals of 3º each. Each “Golden Nugget” also corresponds to a pillar. As there are 60 pillars and 120 Gold Nuggets, each pillar is repeated 2 times in the ring and therefore unlike the 72 Dragons, there are no empty Gold Nuggets. The element of the pillar and its pulse will also associated with each of the Golden Nuggets.
A starting point to use these two rings is by measuring the Dragon and the Nugget from the facing and sitting of a given grave or tomb. Some masters also use these rings for yang zhai (normal Feng Shui of the living). A lot of information can be extracted from these two measurements in yang zhai. The theory is rich and substantial and has many possibilities. It is a must for all that like San He and the history of Feng Shui.