I. The Scope of Feng Shui
Feng Shui is divided into先天 (pre-birth) Feng Shui and 后天 (post-birth) Feng Shui. Pre-birth and post-birth Feng Shui refer to the brief moment when the sperm of the father and the egg of the mother combine; before this moment falls under pre-birth Feng Shui, and after this moment comes under post-birth Feng Shui.
Pre-birth Feng Shui includes paternal Feng Shui and maternal Feng Shui, each having Yin residence (grave) Feng Shui and Yang residence (living space) Feng Shui. The scope of Yang residence Feng Shui further contains dwelling Feng Shui and behavioral Feng Shui.
So-called dwelling Feng Shui refers to the residences before birth (pre-birth) and all residences after birth. Behavioral Feng Shui originally belongs to the category of Yang residence Feng Shui, but due to its significant influence on Yang residence Feng Shui, it has been established as a separate research topic. For instance, consider two twin brothers who have completely identical pre-birth Feng Shui. However, due to differences in behavioral Feng Shui, one may attend elementary or middle school while the other goes on to university or graduate studies, resulting in different Feng Shui outcomes for the two.
Therefore, the scope of Feng Shui is vast and complex.