1. Core Concept (核心概念)
Tian Gan Di Zhi (天干地支)—literally “Heavenly Stems and Earthly Branches”—is China’s ancient system for reckoning time. Developed during the Shang Dynasty (c. 1600–1046 BCE), it remains the backbone of the traditional lunisolar calendar, Chinese astrology, and divination practices.
The system combines:
- 10 Heavenly Stems (天干 - Tiān Gān)
- 12 Earthly Branches (地支 - Dì Zhī)
Together they form a 60-year cycle (六十甲子) by pairing stems and branches in sequential order.
2. The Heavenly Stems (天干)
The ten stems are associated with the Five Elements in their Yin and Yang polarities:
| Stem | Chinese | Element | Polarity |
|---|---|---|---|
| Jia | 甲 | Wood | Yang |
| Yi | 乙 | Wood | Yin |
| Bing | 丙 | Fire | Yang |
| Ding | 丁 | Fire | Yin |
| Wu | 戊 | Earth | Yang |
| Ji | 己 | Earth | Yin |
| Geng | 庚 | Metal | Yang |
| Xin | 辛 | Metal | Yin |
| Ren | 壬 | Water | Yang |
| Gui | 癸 | Water | Yin |
3. The Earthly Branches (地支)
The twelve branches correspond to the Chinese Zodiac animals and the double-hours of the day:
| Branch | Chinese | Zodiac Animal | Time Period |
|---|---|---|---|
| Zi | 子 | Rat | 23:00–01:00 |
| Chou | 丑 | Ox | 01:00–03:00 |
| Yin | 寅 | Tiger | 03:00–05:00 |
| Mao | 卯 | Rabbit | 05:00–07:00 |
| Chen | 辰 | Dragon | 07:00–09:00 |
| Si | 巳 | Snake | 09:00–11:00 |
| Wu | 午 | Horse | 11:00–13:00 |
| Wei | 未 | Goat | 13:00–15:00 |
| Shen | 申 | Monkey | 15:00–17:00 |
| You | 酉 | Rooster | 17:00–19:00 |
| Xu | 戌 | Dog | 19:00–21:00 |
| Hai | 亥 | Pig | 21:00–23:00 |
4. The 60-Year Cycle (六十甲子)
By pairing the 10 stems with the 12 branches, the system produces 60 unique combinations before repeating:
> Jia-Zi (甲子) → Yi-Chou (乙丑) → Bing-Yin (丙寅) → … → Gui-Hai (癸亥)
The current cycle began in 1984 (Jia-Zi Year) and will complete in 2043 (Gui-Hai Year).
Every Chinese New Year marks the transition to the next stem-branch pair, determining the year’s elemental character and zodiac animal. For example, 2024 is Jia-Chen (甲辰)—Wood Dragon year.
5. Applications in Daily Life (生活中的应用)
Calendar & Festivals
Traditional festivals are still scheduled using the stem-branch system:
- The Spring Festival falls on the first day of the first lunar month, but its elemental nature changes annually based on the year’s stem-branch combination.
- Farmers historically used the 24 Solar Terms (which subdivide the Earthly Branches) to schedule planting and harvest.
Fortune-Telling & Astrology (八字命理)
A person’s “Bazi” (八字)—literally “Eight Characters”—is derived from the stem-branch pairs of their birth year, month, day, and hour. These eight characters form the basis of Chinese fortune-telling, marriage compatibility, and career guidance.
Naming Conventions
Parents historically chose names containing characters that balanced the missing elements revealed in a child’s Bazi reading.