Day Pillar #15 · 戊寅
| Position in the cycle | #15 of 60 |
|---|---|
| Heavenly stem 天干 | 戊 — 土 Earth |
| Earthly branch 地支 | 寅 — 木 Wood |
| Nayin 纳音 | 城头土 — City-Wall Earth (Earth) |
| Hidden stems 藏干 | 甲、丙、戊 — 甲 (Wood), 丙 (Fire), 戊 (Earth) |
| Twelve-stage placement 十二长生 | 长生 — Growth (of the stem in its own branch) |
Most modern writing about a weak day master is quantitative. Not enough support, wrong season, add fire. Wuyin (戊寅) is where the classical register does something a quantity-based reading has no slot for at all.
戊寅，受伤之土。最为无力，要生旺火，以资其气。
Wuyin: wounded earth. The most powerless of them, it needs flourishing fire generated for it, to supply its energy.
The short register elsewhere gives the same pillar its physical image and its likes:
戊寅土，堤阜城郭，喜木及火。
Wuyin earth: embankments and city walls. It likes wood, and fire.
Wounded, powerless, wants fire. So far this is ordinary. Then the chapter on its nayin attaches a condition to that same fire, and the condition is of a kind that does not appear anywhere in a modern reading.
凡遇见路旁，为已成之土，不必用火，若无路旁，为未成之土，必须用火；
Wherever roadside earth is met with, this is finished earth and fire need not be used. If there is no roadside earth, it is unfinished earth, and fire must be used.
Roadside earth (路旁土) is another nayin, and it is exactly two pillars: 庚午 Gengwu #7 and 辛未 Xinwei #8. So whether this pillar needs fire at all turns on whether one named pair shows up in the chart. Not on the quantity of fire. Not on the month of birth. On the presence or absence of two of the sixty.
It gets finer in the next clause:
大都城土皆须资木，杨柳癸未最佳，壬午则忌；
City-wall earth generally requires wood to resource it: of willow wood, Guiwei is best, and Renwu is to be avoided.
Willow wood (杨柳木) is the pair 壬午 Renwu #19 and 癸未 Guiwei #20. Same nayin, its two pillars, opposite verdicts — one named best, the other named as the one to avoid.
Nayin is not the unit this prescription runs on. The individual pillar is.
A reading that tracks only element and strength has nowhere to put a rule shaped like that. It can say "this chart needs fire" or "this chart has too much wood." It cannot say "this needs fire unless Gengwu or Xinwei is present," because it has already dissolved Gengwu into metal plus fire and lost the seat.
We are not claiming the rule is correct. We are pointing out that it is specific enough to be wrong, which is more than can be said for most of what replaced it — and that the specificity lives at the level of the named pillar, not the element.
戊寅己卯，气能成物，功以育物，发乎根，壮乎萼蕊，乃曰城头土也；
Wuyin and Jimao: the energy is able to complete things, its work is to nurture them; it issues from the root and thrives in calyx and bud — hence "city-wall earth."
Note the tension worth knowing about: 戊寅 sits at 长生, the growth stage of its own stem in its own branch, and the naming passage is about issuing and thriving — while the verdict passage calls it wounded and most powerless. The register is not embarrassed by this. The image describes what the category is for; the verdict describes what this particular seat can currently do.
The pillar that follows shares this nayin and gets the opposite prescription — see 己卯 Jimao.
The naming passage prints 路傍土 here, while the city-wall chapter and the other 25 occurrences in the book print 路旁. 傍 and 旁 are interchangeable variants with no difference in sense, so we have not treated it as an error — but we record it rather than silently normalising it. If your edition differs, we would like to know.
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.
Enter a birth date and time to get the four pillars, the hidden stems, the nayin and the twelve-stage placements for a real chart — the same tables this page is built on.
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