Day Master · 甲 Jia · Yang Wood
This is the first in a stem-by-stem classical companion to the Day Master series — primary sources, translated and mapped onto the ecosystem frame.
Most modern write-ups call Jia "the big tree": tall, stubborn, upright. The Ming texts are more precise — and more interesting. They give Jia one image and four conditions, and the conditions are where all the useful information lives.
甲木参天，脱胎要火。春不容金，秋不容土。火炽乘龙，水宕骑虎。地润天和，植立千古。
Jia wood towers to the sky; to be reborn it needs fire. In spring it does not tolerate metal; in autumn it does not tolerate earth. When fire blazes, ride the dragon; when water floods, ride the tiger. With moist ground and mild sky, it stands planted for a thousand ages.
Note what this is not: a personality description. Every clause is a condition — what this system needs, fears, and does under specific loads. That is the ecosystem frame, written six centuries early.
San Ming Tong Hui is blunter. Jia is 阳木, yang wood — first of the ten stems, presiding over the four seasons:
在天为雷为龙，在地为梁为栋。
In heaven it is thunder and the dragon; on earth it is the beam and the ridgepole.
Beam. Ridgepole. The text then makes the move most modern summaries miss:
死木者，刚木也，须仗斧斤斫削方成其器。
Dead wood is hard wood — it must rely on the axe to be hewn into a vessel.
"Dead" here is not morbid; it is structural wood as opposed to growing greenwood (that is 乙 Yi, the living wood, next in the series). Jia's endgame was never to stay a tree. It is to become the load-bearing beam — and that only happens with the axe. Metal, pressure, discipline, editing: the thing that cuts you is the thing that makes you useful. A Jia Day Master that never meets its metal just grows tall and hollow — which is exactly the 脱胎要火 warning from the other direction: without an outlet (fire) and a shaping force (metal, in season), height is all it has.
The best mechanism in the whole passage: soaked in still water (死水), Jia timber does not rot — like pilings that harden underwater. But drag it ashore into rain-and-sun cycles and it dries, cracks, rots, and catches fire. Same element, opposite outcome, decided entirely by regime.
A Jia system holds up astonishingly well under steady, even total, immersion — constant heavy load, constant environment. What breaks it is alternation: wet-dry, hot-cold, on-off. Stability is not a preference for this Day Master; it is a preservation condition.
The text closes the loop with 甲木死于午 — Jia dies at Wu, peak fire — citing the classic line:
木不南奔。
Wood does not run south.
Fire is Jia's output — it is the child of wood — and the mechanism is stated cold:
子旺母衰。
When the child grows strong, the mother wanes.
Jia needs fire to matter (脱胎要火), yet dies where fire peaks. Both are true, and the pair is the whole lesson: output is necessary and consuming. A Jia that never expresses stays raw timber; a Jia that only expresses burns its own substance. The verse's remedies are pure engineering — 火炽乘龙, when fire blazes ride the dragon (辰, moist earth that banks the flame); 水宕骑虎, when water floods ride the tiger (寅, Jia's own root, to absorb it).
One image, four conditions, zero fortune-telling. That is the method the classics actually use.
Sources: 《三命通会》 (San Ming Tong Hui, Ming, 万民英) and 《滴天髓》 (Di Tian Sui) — both quoted from local plain-text editions and verified character by character. Translations are ours. Corrections are welcome.
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