The three stylish subjects are:
(1) Tai Yi Shen Shu 太乙神數
(2) Qi Men Dun Jia 奇門遁甲
(3) Liu Ren 六壬
Tai Yi is based mainly on Tian Yuan 天元.
Qi Men is based mainly on Di Yuan 地元.
Liu Ren is based manily on Ren Yuan 人元.
Tai Yi is used to divine national (and international) events, changes in climate, and natural disasters.
Qi Men is used to find out the best direction and timing for important human events. In the old days, it was used in military affairs.
Liu Ren is used to divine human affairs which can be trifle everyday matters.
Like every other metaphysical subject, in the beginning, it is important to understand the formulation and interpretation according to established rules. At a more advanced stage, the rules can be forgotten. The ultimate goal is have the subject integrated into the diviner's spirit and become one.