Yin and yang
The polarity every stem and branch carries, splitting each element into an outward and an inward form.
In one sentence
The polarity every stem and branch carries, splitting each element into an outward and an inward form.
How it is used
It is why yang wood and yin wood read differently though both are wood, and why one element relationship splits into two of the Ten Gods depending on whether the polarities match. In our readings it describes a style of expression, not a gender and not a ranking: yang is not stronger and yin is not weaker. The polarity we ask for when you enter your details is used only to decide the direction your luck cycles run.