《周易参同契》 (Zhou Yi Can Tong Qi) is a Taoist Classic regarding the principles and methods of self-cultivation for enlightenment and longevity. On the surface, one may think that the Classic has little or no correlation to Fengshui.

Although it is a Religious Taoism Classic (道教经典), 《周易参同契》 is also built on the basis of Philosophical Taoism (道家之道) and 易 principles (易理), observing the Principles or Way of Nature. Thus, the name 参同契. In the last section of the Classic 《下篇》, the Classic says "大易情性，各如其度。黄老用究，较而可御。炉火之事，真有所据。三道由一，俱出径路。枝茎华叶，果实垂布。正在根株，不失其素。诚心所言，审而不误。"

Since the Way of Fengshui (风水之道) is inseparable from 易 principles, and 易 being one’s study and learning of the Nature, underlying principles in 《周易参同契》and Fengshui is naturally similar.

For example, in the middle section of the Classic 《中篇》, the Classic says "子南午北，互为纲纪。 一九之数，终而复始。"

Do you know what this statement and its underlying principles relate to in Fengshui? This statement contains principles in one of the 四决 of Xuan Kong Liu Fa (玄空六法薪传四决之一的原理)!