Gēng 庚, the yang Metal day master of BaZi

Gēng 庚 is the seventh Heavenly Stem, yang Metal, and the day master of any BaZi chart whose day stem it is. The classical images make it ore and iron, and the moon in the sky. The 滴天髓 gives it the hardest character of the ten, clear with water and sharp with fire, able to beat 甲 but yielding to 乙. As a day master it is rooted in 申 and 巳.

Meaning

The 滴天髓 gives each stem a verse of eight short lines. For 庚 it reads, in the 輯要 text:

庚金帶煞，剛強為最，得水而清，得火而銳，土潤則生，土乾則脆，能勝甲兄，輸於乙妹。

In our translation: Gēng metal carries the killing force; of all it is the hardest and strongest. With water it turns clear; with fire it turns sharp. Moist earth gives it life; dry earth makes it brittle. It can beat its elder brother 甲, and loses to its little sister 乙.

The killing force (煞) is the language of autumn, metal's season; the 三命通會 says 庚 holds the power of autumn's culling. Its defeat by 乙 is their combination (乙庚合), which binds the hard metal to the soft wood. The commentary of the 輯要 calls 庚 the essence of the white star, Venus.

The 三命通會 makes 庚 wind and frost in heaven and iron on earth, forged in the furnace of 巳 into bells and tripods; it is born in 巳. Its sky image is the moon, white and brightest in autumn. The 窮通寶鑑 finds the 庚 of the first month cold and buried; it wants 丙 to warm it and 甲 to loosen the thick earth over it.

Our chart calls 庚 raw metal: decisive, just, strong and commanding, with harshness and bluntness as its cost. That is EsoTerrier's modern image, labelled as ours; the texts' wind, frost, iron and moon stand beside it.

In a chart

A 庚 day master has roots wherever 庚 is hidden in a branch: 巳 Sì (middle qi), 申 Shēn (main qi). Its 祿, the branch where its qi comes into office (臨官), is 申; the branch after it, 酉, is its blade (陽刃). It is born (長生) in 巳 and, as a yang stem, runs the twelve stages forward from there; the stages are phases of its qi.

It combines with 乙 Yǐ (天干五合), a pair the 三命通會 calls 仁義之合 (the match of benevolence and righteousness), leaning to Metal; it clashes with 甲 Jiǎ. Its own phase is strongest in autumn.

To a 庚 day master the ten stems are: 甲 Indirect Wealth (偏財); 乙 Direct Wealth (正財); 丙 Seven Killings (七殺); 丁 Direct Officer (正官); 戊 Indirect Resource (偏印); 己 Direct Resource (正印); 庚 Friend (比肩); 辛 Rob Wealth (劫財); 壬 Eating God (食神); 癸 Hurting Officer (傷官). A second 庚 elsewhere in the chart is a Friend; the day stem itself is the Day Master and is not one of the Ten Gods.

What this page leaves out

The classical chapters on 庚 also say, in the idiom of their age, what such a chart means for rank, kin, marriage and fortune. We record that they do and repeat none of it. Nor do we say whether a 庚 day master is strong or weak, or which useful god it needs: the tradition weighs both, and EsoTerrier computes neither.

Correspondences

Each item with how it stands: “sourced” is in the work cited, “our construction” is EsoTerrier’s own, and “disputed” means the sources disagree.

Opening of the 滴天髓 verse: 「庚金帶煞」 sourced
Sky image, 三命通會: The moon (月) sourced
In heaven and on earth, 三命通會: In heaven wind and frost, on earth iron (在天為風霜，在地為金鐵); it holds the power of autumn's culling sourced
The first month, 窮通寶鑑: In the first month 庚 is cold and buried; it wants 丙 to warm it and 甲 to loosen the thick earth (正月庚金) sourced
Combination, 三命通會: With 乙: 仁義之合 (the match of benevolence and righteousness) sourced
Nobleman star (天乙貴人): 丑 and 未; a symbolic star we do not chart yet sourced
Academic star (文昌): 亥; a symbolic star we do not chart yet sourced
Our image, traits and challenge: Raw metal: decisive, just, strong and commanding; its challenge: harshness, and bluntness our construction
Raw metal as the classical meaning: A modern image; the classics give the ones above disputed
First meaning of the character: Uncertain; the stems are first attested as day names of the Shang week disputed

How the schools read it

滴天髓, the verse: The hardest stem, clear with water and sharp with fire; it beats 甲 and yields to 乙. Attributed to 京圖 of the Song or to Liu Bowen; one edition study dates the text mid-Ming or later.
任鐵樵, 滴天髓闡微 (after 1820): Reads 剛健為最 and 能贏甲兄, "strongest and most robust" and "it can win over elder brother 甲".
三命通會 (Ming): Wind and frost, iron forged into bells and tripods; the moon.
窮通寶鑑 (Qing): Cold, buried metal in the first month, wanting sun and loosened earth.
Modern English teaching: The one-word image, raw metal, a simplification of the classical images.
EsoTerrier: Shows raw metal as its own image, labelled, beside the texts.

Claims about it

"Raw metal" is the traditional meaning of 庚.
disputed

What the record shows: It is a modern teaching image, and ours on the chart. The 三命通會 gives wind and frost, iron and the moon; the 滴天髓 gives the killing force of autumn.
The day stem is itself a Ten God, the Friend (比肩).
false

What the record shows: A 庚 in another pillar is a Friend to a 庚 day master; the day stem itself is the reference point, labelled Day Master (日主) by every tool we surveyed.
A 庚 day master can be scored strong or weak, and its useful god computed.
disputed

What the record shows: The classics ground the useful god in at least four different ways. EsoTerrier computes neither the strength nor the useful god.
The classical chapters on 庚 tell a person's rank, marriage and length of life.
told as lore

What the record shows: The texts do make such pronouncements, in the idiom of their age. We take only their images and the logic of the phases.

Elsewhere on EsoTerrier

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Gēng 庚, yang Metal: the hard metal that yields to its sister

Facts