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).

Period of the Property (宅之元运). Currently, with regards to ascertaining the period of the property, different views have been advocated and widely discussed by many Fengshui practitioners.

With the increase in public's awareness on Fengshui over the years, the number of Fengshui courses being offered by Fengshui practitioners is on the rise as well. Courses typically offered are widely known Fengshui applications such as Flying Stars or Xuan Kong Fei Xing (玄空飞星), Xuan Kong Da Gua (玄空大卦), Ba Zhai (八宅), San He (三合), Landform/ Form Analysis (长眼法、形峦) etc.

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.