In the application of Xuan Kong Liu Fa (玄空六法), Ci Xiong Jue (雌雄决) is of foremost priority. This is reflected in the first sentence of the Fengshui Classic Qing Nang Xu (青囊序), where the Classic has also pointed out the usage sequence of the 四决 of Xuan Kong Liu Fa, namely Ci Xiong Jue (雌雄决), Jin Long Jue (金龙决), Ai Xing Jue (挨星决) and Cheng Men Jue (城门决).

Often, the focus of many Fengshui practitioners is on Li Qi (理气). However, such focus is wrong. Why is this so?

《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.

杨公养老看雌雄，

天下诸书对不同。

The opening of all classics is evidently the most important. Qing Nang Xu is no different. However, the emphasis from most annotations on the first sentence of Qing Nang Xu is wrong. Most commented on the reason for the choice of the word Ci Xiong (雌雄) over Yin Yang (阴阳).  In fact, the emphasis actually should be on the word (看) or See.

It is common for some to understand Xuan Kong Liu Fa (玄空六法) as six different methods of Fengshui, comprising Xuan Kong (玄空), Ci Xiong (雌雄), Jin Long (金龙), Ai Xing (挨星), Cheng Men (城门) and Tai Sui (太岁).