How it works
Stems & Branches constitutional mapping, explained.
The Stems & Branches (干支, Gān Zhī) constitutional map is a classical Chinese medicine method that derives a patient's energetic constitution from their birthdate. Here's what it is, how it works, and what StemMap does with it.
What is constitutional mapping?
In classical Chinese cosmology, time moves in cycles described by the 天干 (Ten Heavenly Stems) and 地支 (Twelve Earthly Branches). Each year is named by one stem-branch pair — 60 pairs in total, forming the sexagenary cycle. A person's birth year determines which qi was dominant at birth, which in turn shapes their constitutional tendencies.
The constitutional map — sometimes called the Wǔ Yùn Liù Qì (Five Movements and Six Qi) chart — places the twelve organs on a five-element wheel, showing which are in excess, which are in deficiency, and how they relate to each other for that half-year period.
The Ten Stems and Twelve Branches
The Ten Heavenly Stems (甲乙丙丁戊己庚辛壬癸) pair with the five elements, each element having a yang and yin stem. The Twelve Earthly Branches (子丑寅卯辰巳午未申酉戌亥) correspond to the twelve organs and the twelve two-hour periods of the Chinese clock. Together they name every year in a 60-year cycle.
Why the year boundary is in early February
The Chinese solar year begins not on January 1st, but around February 4th (the Lì Chūn 立春 solar term — the start of spring). This means someone born in late January is assigned to the previousyear's stem and branch. StemMap handles this boundary automatically using the 1924–2043 date-boundary table — you enter the calendar date, and the correct year and half-year are resolved.
How the map is built
Each half-year map contains:
- The Great Movement — the dominant element for the year (excess or deficiency).
- The Six Divisions — the upper and lower halves of the body are each governed by one of six energetic layers (Tai Yang, Yang Ming, Shao Yang, Tai Yin, Shao Yin, Jue Yin).
- Organ placements — the twelve organs are placed on the five-element wheel, some inside the circles, some outside, with specific roles.
- The connecting line — drawn between two circles, showing the primary energetic relationship.
- Inner-energy dots — placed inside circles to show secondary qi influences.
- Corrective energy — organs in the centre of the wheel, representing the body's self-correcting mechanism.
- Five analysis tables — Like/Unlike Qi, Elements (EL/EN), Four Possibilities, F.G/F.D, and m.o.
What StemMap automates — and what it doesn't
StemMap performs the lookup: it resolves the year and half, retrieves the pre-computed map, and renders the wheel and tables. It does notinterpret the map, recommend treatments, or replace clinical judgement. The map is a reference tool — what you do with it is your practice.
Try it: a worked example
Enter a birthdate below and see the map build in real time. Try 14 March 1994 — you'll see the 1994 first-half map, with Gall Bladder inside Earth, Pericardium outside Fire (underlined), and the full set of analysis tables.