The Wood principle (phase or “element”) mu 木 is associated with the idea of spring, although it does not represent it concretely.

As mentioned in other entries, Wood is the young yet vigorous yang principle, representing a reaction to the preceding yin dominance in natural cycles. Hence its vigorous, expansive, and self-confident nature.

However, it should be noted that the Wood “element” can manifest through two aspects, although they share a common “raw material.”

Yang Wood (jia 甲), represented by a Tree, represents Wood in its most obvious manifestation, that of physical vitality, along with a robustness and inflexibility suggested by the image of a large tree.

In contrast, Yin Wood (yi 乙), represented by a Plant, a Shrub, or a Flower, exhibits the same vitality but in a much subtler way. When the wind blows, the plant bends, only to regain its initial position soon after. This is, in fact, a deceptive “weakness” that can entail an irresistible power of seduction.

The two manifestations (and their respective celestial stems) of the Wood “element” become more evident when they correspond to the Day Master (or “Personal Element”) of the person to whom the Bazi birth chart refers.