Stems and branches (Gan Zhi)
Definition
Gan Zhi combines the ten Heavenly Stems and the twelve Earthly Branches. Interwoven they form the sixty Jia-Zi cycle that marks year, month, day, and hour. In charting, stems and branches are both time coordinates and carriers of yin/yang and Five Phases.
Structure
- Heavenly Stems: Jia Yi Bing Ding Wu Ji Geng Xin Ren Gui — see Ten Heavenly Stems
- Earthly Branches: Zi Chou Yin Mao Chen Si Wu Wei Shen You Xu Hai — see Twelve Earthly Branches
- Yin–yang: each stem and branch has a fixed polarity — see Yin and yang
- Five Phases: stems and branches map to the Five Phases — see Five Phases
Use across systems
- BaZi: year, month, day, and hour pillars are four stem–branch pairs; method: Four-pillars charting.
- Zi Wei: placing the life palace and stars depends on lunar month/day and hour branch; the underlying time order relates to the stem–branch calendar.
- Liu Yao: charting conventions such as Na Jia use stems/branches and the six relatives.
Sixty Jia-Zi
Stems and branches rotate yang-with-yang, yin-with-yin, yielding Jia-Zi, Yi-Chou … Gui-Hai (sixty pairs), then cycle again. Year and day pillars both fall on this cycle.