San He (Three Harmony): The Trine Combinations

Definition

San He (Three Harmony) is one of the most important combining relationships among the [Earthly Branches](/bazi/glossary/di-zhi): three branches unite to produce a strong elemental qi that can markedly shift the chart's balance.

The Four Trines

- **Shen–Zi–Chen** → **Water**; - **Hai–Mao–Wei** → **Wood**; - **Yin–Wu–Xu** → **Fire**; - **Si–You–Chou** → **Metal**. Each is formed from that element's **Long-Life, Emperor, and Tomb** branches (Water: Shen=Long-Life, Zi=Emperor, Chen=Tomb). All three present is a "full" trine; two is a "half" trine (e.g. Shen–Zi, Zi–Chen).

Nature and Use

- A formed trine greatly amplifies that element — multiplying a [Useful God](/bazi/glossary/yong-shen), or worsening an unfavorable one. - A half-trine is weaker than a full one; whether the central branch (the Emperor, e.g. Zi) is present matters most. - A trine can be broken by a clash, and can also "tie up" a branch that would otherwise clash or control.

Common Misconceptions

**1: Any two branches make a trine.** A half-trine needs the central (Emperor) branch to be strong; two tombs or two long-lives alone are weak. **2: A trine is always good.** If the produced element is unfavorable, it worsens the chart's pressure.

Significance in Chart Analysis

Trines reshape elemental strength — key to judging [strength](/bazi/glossary/qiang-ruo) and the fortune of cycles. With the [Six Harmonies](/bazi/glossary/liu-he) and Six Clashes they form the branch-relationship web. See your chart's trines with the [free BaZi calculator](/bazi/chart).