Na Jia (stem-branch assignment)
Definition
Na Jia is the practice of giving every line of a hexagram a stem-branch pair. Only after it is applied does a line have a Five-Phase value — and only then can six relatives, strength and control relationships have somewhere to land.
The distinction worth keeping: a trigram speaks in images; Na Jia converts it into elements that can be compared. Without it you can read the classic's statements but you cannot ask "is this line strong".
Assignment
- Qian takes Jia and Ren, Kun takes Yi and Gui: the parent hexagrams take two stems, one for the inner three lines and one for the outer three.
- The other six take one stem each: Zhen-Geng, Xun-Xin, Kan-Wu, Li-Ji, Gen-Bing, Dui-Ding.
- Branches advance or retreat by line position: yang hexagrams run forward, yin hexagrams run backward, with the starting point fixed per hexagram.
So Qian reads, bottom to top: Jia-Zi, Jia-Yin, Jia-Chen, Ren-Wu, Ren-Shen, Ren-Xu. Kun reads: Yi-Wei, Yi-Si, Yi-Mao, Gui-Chou, Gui-Hai, Gui-You.
Use
- Fix the lower and upper trigrams, then take three lines of stems and branches from each table.
- Convert branches to elements, then derive six relatives against the palace element — see Six relatives.
- Read together with Shi and Ying and the moving line: when a line moves, its stem-branch pair changes, and so does its relative.
Boundaries
- Na Jia is a charting convention, not scripture. The Zhou Yi gives statements; the stem-branch layer was added by later practice.
- Schools differ slightly on the starting rule for yin and yang hexagrams; confirm which table a source uses before quoting a specific line.