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Heavenly Stems and Earthly Branches

    Heavenly stems and earthly branches are collectively known as Stem-Branch or Gan-Zhi.  The 10 heavenly stems are Jia, Yi, Bing, Ding, Wu, Ji, Geng, Xin, Ren and Gui.  The 12 earthly branches are Zi, Chou, Yin, Mao, Chen, Si, Wu, Wei, Shen, You, Xu and Hai.  Each heavenly stem is paired with an earthly branch to form the Gan-Zhi sexagenary cycle that starts with Jia-Zi (Table 2). 

         Table 2             The Gan-Zhi sexagenary cycle.

1

2

3

4

5

6

7

8

9

10

11

12

Jia-Zi

Yi-Chou

Bing-Yin

Ding-Mao

Wu-Chen

Ji-Si

Geng-Wu

Xin-Wei

Ren-Shen

Gui-You

Jia-Xu

Yi-hai

13

14

15

16

17

18

19

20

21

22

23

24

Bing-Zi

Ding-Chou

Wu-Yin

Ji-Mao

Geng-Chen

Xin-Si

Ren-Wu

Gui-Wei

Jia-Shen

Yi-You

Bing-Xu

Ding-Hai

25

26

27

28

29

30

31

32

33

34

35

36

Wu-Zi

Ji-Chou

Geng-Yin

Xin-Mao

Ren-Chen

Gui-Si

Jia-Wu

Yi-Wei

Bing-Shen

Ding-You

Wu-Xu

Ji-Hai

37

38

39

40

41

42

43

44

45

46

47

48

Geng-Zi

Xin-Chou

Ren-Yin

Gui-Mao

Jia-Chen

Yi-Si

Bing-Wu

Ding-Wei

Wu-Shen

Ji-You

Geng-Xu

Xin-Hai

49

50

51

52

53

54

55

56

57

58

59

60

Ren-Zi

Gui-Chou

Jia-Yin

Yi-Mao

Bing-Chen

Ding-Si

Wu-Wu

Ji-Wei

Geng-Shen

Xin-You

Ren-Xu

Gui-Hai

        The use of Gan-Zhi to record the years, months, days and hours all started in different periods in history.  The Gan-Zhi years and days have been used for two to three thousand years.  In ancient time, the months and the hours (the hours are called shichen) were named after the earthly branches only (Figure 1 and Table 3).   Through the years, people started to make stems of the months after the stem of the year (Table 4), and stems of the hours after the stem of the day (Table 5).  The Gan-Zhi's of year, month, day and hour together form the Eight Characters.


         Table 3            The relationship between the 12 shichen and the present time system.

12 shichen

The present time system

Zi hour

23 hour to 01 hour

Chou hour

01 hour to 03 hour

Yin hour

03 hour to 05 hour

Mao hour

05 hour to 07 hour

Chen hour

07 hour to 09 hour

Si hour

09 hour to 11 hour

Wu hour

11 hour to 13 hour

Wei hour

13 hour to 15 hour

Shen hour

15 hour to 17 hour

You hour

17 hour to 19 hour

Xu hour

19 hour to 21 hour

Hai hour

21 hour to 23 hour

         Table 4          The relationship between the stem of the year and the stem of the month.

The stem
of the year

The stem of the month

Yin
1st
month

Mao
2nd
month

Chen
3rd
month

Si
4th
month

Wu
5th
month

Wei
6th
month

Shen
7th
month

You
8th
month

Xu
9th
month

Hai
10th
month

Zi
11th
month

Chou
12th
month

Jia or Ji

Bing

Ding

Wu

Ji

Geng

Xin

Ren

Gui

Jia

Yi

Bing

Ding

Yi or Geng

Wu

Ji

Geng

Xin

Ren

Gui

Jia

Yi

Bing

Ding

Wu

Ji

Bing or Xin

Geng

Xin

Ren

Gui

Jia

Yi

Bing

Ding

Wu

Ji

Geng

Xin

Ding or Ren

Ren

Gui

Jia

Yi

Bing

Ding

Wu

Ji

Geng

Xin

Ren

Gui

Wu or Gui

Jia

Yi

Bing

Ding

Wu

Ji

Geng

Xin

Ren

Gui

Jia

Yi

         Table 5          The relationship between the stem of the day and the stem of the hour.

The stem
of the day
The stem of the hour
Zi
hour

Chou hour

Yin hour

Mao hour

Chen hour

Si
hour
Wu hour Wei hour Shen hour You hour Xu hour Hai hour
Jia or Ji

Jia

Yi

Bing

Ding

Wu

Ji Geng Xin Ren Gui Jia Yi
Yi or Geng

Bing

Ding

Wu

Ji

Geng

Xin Ren Gui Jia Yi Bing Ding
Bing or Xin

Wu

Ji

Geng

Xin

Ren Gui Jia Yi Bing Ding Wu Ji
Ding or Ren

Geng

Xin

Ren

Gui

Jia Yi Bing Ding Wu Ji Geng Xin
Wu or Gui

Ren

Gui

Jia

Yi

Bing Ding Wu Ji Geng Xin Ren Gui
Last revision date: <20 Dec 2012>