Stage 1 · Term 6 of 34
Yin & Yang 阴阳
Yīn Yáng
甲 is yang wood — a pillar tree; 乙 is yin wood — a climbing vine. The polarity attached to every element: yang (expansive, declared) and yin (subtle, adaptive). Same element, different temperament; the difference matters everywhere in BaZi.
In the classics
Every stem and branch carries a polarity, and the classics treat the distinction as temperamental, not moral: 《滴天髓》's stem verses describe yang stems as expanding and declaring, yin stems as adapting and permeating.
In a chart
Polarity does quiet, decisive work. It splits each element's pair of stems into two characters with different strategies (丙 the sun versus 丁 the lamp). It decides which of two same-relation Ten Gods a character becomes — control by the opposite polarity is Direct Officer; by the same polarity, Seven Killings — a distinction that changes the entire tone of the star. And it patterns the branches, which alternate yang and yin around the cycle.
Worked example
For a 甲 (yang wood) Day Master, 辛 (yin metal) is the orderly Direct Officer while 庚 (yang metal) is the forceful Seven Killings. The element relation is identical; only polarity differs — and everything about how the pressure feels changes.
Where beginners misread it
Hearing "yin" as weak and "yang" as strong. 乙 the vine survives storms that snap 甲 the tree; adaptability is not weakness.
The classical rules here are public; the lineage method for applying them to a specific chart is taught, not read — see Yixin Academy's courses.
learnwithyixin.com/courses →What does Yin & Yang mean in BaZi?
甲 is yang wood — a pillar tree; 乙 is yin wood — a climbing vine. The polarity attached to every element: yang (expansive, declared) and yin (subtle, adaptive). Same element, different temperament; the difference matters everywhere in BaZi.