Yuanzi Encyclopedia
Ten Heavenly Stems & Twelve Earthly Branches
Systematic reference for the Yin-Yang, Five Elements, seasonal directions, and reading priorities of the Ten Heavenly Stems and Twelve Earthly Branches.
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The Ten Heavenly Stems and Twelve Earthly Branches together form the sixty-pillar sexagenary cycle (Jiazi), constituting the Year, Month, Day, and Hour Pillars of BaZi. Heavenly Stems typically observe prominent, outward dynamics, whereas Earthly Branches embody seasons, hours, spatial directions, and Hidden Stems. They represent different layers of a single integrated system; one should not mechanically treat stems as "the exterior" and branches as "the interior."
Ten Heavenly Stems Reference
| Heavenly Stem | Yin-Yang & Five Elements | Common Natural Analogy | Reading Reminder |
|---|---|---|---|
| Jia (甲) | Yang Wood | Tall trees, timber, vigorous growth | Check for roots, water supply, and proper thinning/drainage |
| Yi (乙) | Yin Wood | Flowering plants, vines, flexible wood | Focus on adaptability and spread; flexibility is not weakness |
| Bing (丙) | Yang Fire | Sun, radiant light and heat | Focus on clarity and dissemination; assess season and obstruction |
| Ding (丁) | Yin Fire | Candle flame, hearth fire | Focus on sustained focus and heat; check fuel source and surroundings |
| Wu (戊) | Yang Earth | Mountains, embankments, solid soil | Focus on containment and stability; assess excessive dryness or dampness |
| Ji (己) | Yin Earth | Garden soil, fertile fields | Focus on nurturing and integration; check water and wood coordination |
| Geng (庚) | Yang Metal | Ore, axes, unrefined metal | Focus on decisiveness and reform; assess smelting and flow |
| Xin (辛) | Yin Metal | Jewelry, refined gems | Focus on refinement and precision; check cleansing and protection |
| Ren (壬) | Yang Water | Rivers, oceans, surging waters | Check headwaters, destination, embankments, and season |
| Gui (癸) | Yin Water | Rain, dew, spring water | Check gathering, infiltration, temperature, and reception |
Natural analogies are metaphors for reading classical texts, not rigid personality tests claiming "Jia Wood people are like giant trees" or "Geng Metal people suit specific careers." The same Day Stem behaves differently across different month commands, root strengths, and combinations.
Twelve Earthly Branches Reference
| Earthly Branch | Yin-Yang & Primary Element | Solar Term Month Start | Two-Hour Period |
|---|---|---|---|
| Zi (子) | Yang Water | Daxue (Major Snow) | 23:00–00:59 |
| Chou (丑) | Yin Earth | Xiaohan (Minor Cold) | 01:00–02:59 |
| Yin (寅) | Yang Wood | Lichun (Start of Spring) | 03:00–04:59 |
| Mao (卯) | Yin Wood | Jingzhe (Awakening of Insects) | 05:00–06:59 |
| Chen (辰) | Yang Earth | Qingming (Pure Brightness) | 07:00–08:59 |
| Si (巳) | Yin Fire | Lixia (Start of Summer) | 09:00–10:59 |
| Wu (午) | Yang Fire | Mangzhong (Grain in Ear) | 11:00–12:59 |
| Wei (未) | Yin Earth | Xiaoshu (Minor Heat) | 13:00–14:59 |
| Shen (申) | Yang Metal | Liqiu (Start of Autumn) | 15:00–16:59 |
| You (酉) | Yin Metal | Bailu (White Dew) | 17:00–18:59 |
| Xu (戌) | Yang Earth | Hanlu (Cold Dew) | 19:00–20:59 |
| Hai (亥) | Yin Water | Lidong (Start of Winter) | 21:00–22:59 |
Month commands transition at the exact astronomical moment of each solar term (Jie), not simply on lunar calendar month boundaries. The Zi hour crosses midnight, but whether 23:00–23:59 belongs to the next day depends on the declared day boundary standard.
How the Sixty Sexagenary Combinations (Jiazi) Form
Heavenly Stems and Earthly Branches pair in fixed sequence: Jia-Zi, Yi-Chou, Bing-Yin, and so on. Yang stems pair only with Yang branches, and Yin stems pair only with Yin branches. The ten stems and twelve branches cycle through sixty unique pairs before returning simultaneously to the beginning, creating the sixty Jiazi.
The sixty Jiazi cyclically mark years, months, days, and hours, but the boundary rules for the four pillars differ: years and months depend on solar terms, days depend on day boundaries, hour branches span two-hour blocks, and hour stems derive from the day stem. Knowing only a zodiac animal or Na Yin pair cannot reconstruct a full BaZi chart.
Why Earthly Branches Are More Complex Than a Single Element
Each Earthly Branch conceals one to three Heavenly Stems (Hidden Stems); thus, one cannot treat Yin simply as Wood or Chou simply as Earth. Branches also participate in Six Harmonies, Three Harmonies, Seasonal Combinations, Clashes, Punishments, Harms, and Destructions, functioning differently according to season, position, and luck cycles.
First use Yin-Yang, Five Elements & Interactions to understand the relational language, then read Earthly Branch Hidden Stems & Month Command to place stems and branches within concrete chart structures.
What to Avoid When Using Stem-Branch Tables
- Inferring complete personality, career, wealth, or health from an isolated Day Stem or zodiac animal;
- Treating natural analogies as modern scientific causalities;
- Overlooking Hidden Stems, solar-term months, and historical time boundaries;
- Conflating the sixty Jiazi, Na Yin, and symbolic stars (Shensha) into an unranked, arbitrary label system.
Verify this concept on your chart
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