The ten Heavenly Stems
Stems are the “active” layer: each one is a pure combination of an element and a polarity. In a chart they sit on top of the branches.
| # | Stem | Element | Polarity | Year example |
|---|---|---|---|---|
| 1 | Jia 甲 | Wood | yang | 1984, 2044 |
| 2 | Yi 乙 | Wood | yin | 1985, 2045 |
| 3 | Bing 丙 | Fire | yang | 1986, 2046 |
| 4 | Ding 丁 | Fire | yin | 1987, 2047 |
| 5 | Wu 戊 | Earth | yang | 1988, 2048 |
| 6 | Ji 己 | Earth | yin | 1989, 2049 |
| 7 | Geng 庚 | Metal | yang | 1990, 2050 |
| 8 | Xin 辛 | Metal | yin | 1991, 2051 |
| 9 | Ren 壬 | Water | yang | 1992, 2052 |
| 10 | Gui 癸 | Water | yin | 1993, 2053 |
The twelve Earthly Branches
Branches carry an animal, an element, a two-hour period of the day, and one to three hidden stems. The hour column is why the Hour pillar depends on the birth time; the month column is why the Month pillar depends on the solar term rather than the calendar.
| Branch | Animal | Element | Hours | Solar month | Hidden stems |
|---|---|---|---|---|---|
| Zi 子 | Rat | Water | 23:00–01:00 | month 11 (Zi) | Gui 癸 |
| Chou 丑 | Ox | Earth | 01:00–03:00 | month 12 (Chou) | Ji 己 · Gui 癸 · Xin 辛 |
| Yin 寅 | Tiger | Wood | 03:00–05:00 | month 1 (Yin) | Jia 甲 · Bing 丙 · Wu 戊 |
| Mao 卯 | Rabbit | Wood | 05:00–07:00 | month 2 (Mao) | Yi 乙 |
| Chen 辰 | Dragon | Earth | 07:00–09:00 | month 3 (Chen) | Wu 戊 · Yi 乙 · Gui 癸 |
| Si 巳 | Snake | Fire | 09:00–11:00 | month 4 (Si) | Bing 丙 · Wu 戊 · Geng 庚 |
| Wu 午 | Horse | Fire | 11:00–13:00 | month 5 (Wu) | Ding 丁 · Ji 己 |
| Wei 未 | Goat | Earth | 13:00–15:00 | month 6 (Wei) | Ji 己 · Ding 丁 · Yi 乙 |
| Shen 申 | Monkey | Metal | 15:00–17:00 | month 7 (Shen) | Geng 庚 · Ren 壬 · Wu 戊 |
| You 酉 | Rooster | Metal | 17:00–19:00 | month 8 (You) | Xin 辛 |
| Xu 戌 | Dog | Earth | 19:00–21:00 | month 9 (Xu) | Wu 戊 · Xin 辛 · Ding 丁 |
| Hai 亥 | Pig | Water | 21:00–23:00 | month 10 (Hai) | Ren 壬 · Jia 甲 |
Note the Zi branch: the Zi hour runs from 23:00 to 01:00, which is why the late Zi hour rule exists.
How the sixty combinations work
Pair the first stem with the first branch, the second with the second, and so on. Because 10 and 12 share a factor of 2, only 60 of the 120 possible pairings ever occur, and the sequence repeats every 60 steps. That single cycle drives years, months, days and hours — all four pillars are counts along it.
- Years: 1984 was Jia-Zi, the first of the cycle. 2024 was Jia-Chen.
- Days: the day count is an independent 60-day cycle; it does not restart with the year.
- Hours: the hour branch comes from the clock, and the hour stem from the Day stem.
Reading the two layers together
A pillar always has a stem over a branch, and traditional reading treats them as two statements about the same thing: the stem as the visible, expressed quality; the branch as the ground it stands on. A strong stem over a weak branch reads differently from the reverse, which is why the hidden stems inside each branch matter so much.
The hidden stems are also where the Ten Gods get interesting: a chart can look empty of Wealth on the surface and still have three Wealth stems hidden inside branches.