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

⇒ The 24 Solar Terms

⇐ The Chinese System of Heaven Stems and Earth Branches

⇑ Chinese Calendar - History and Traditions

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