BaZi day master · 4 of 10
Yin Fire Day Master (丁火) in BaZi
丁 is yin fire — the lamp, the candle, the hearth. It is fire with an intention: attention pointed at one thing at a time rather than spread over everything. If your day pillar begins with 丁, this is the character every other part of your chart is described relative to.
The short version
丁 is fire that has chosen a target — small, deliberate, and hard to ignore.
Classical practice treats 丁 as concentrated rather than lesser: the candle is read as more decisive than the daylight it is compared to.
Is your day master 丁?
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Enter your birth date — nothing else is required for this answer. If the result comes back with a different stem, the profile for it is one click away at the bottom of the page.
How it’s calculated
- 1
Take the day pillar
The day pillar advances exactly one step per calendar day with no gaps and no leap corrections. That continuous count is what makes it reliable: it does not depend on the calendar reform, the timezone or the season.
- 2
Read its heavenly stem
The stem of that pair is the day master. 丁 is the 4th of the ten stems, so “is my day master 丁?” reduces to one question about one character — and it can be answered from the date alone.
- 3
Set it as the reference
Once 丁 is fixed, the other seven characters stop being a list and become relationships. Every stem in the chart is named by how it stands to 丁 — that is the table on this page, and it is different for each of the ten stems.
The full rule set — every convention, in order, with the engine field names — is published on the methodology page.
What 丁 means as a day master
丁 is fire at yin: the lamp, the candle, the fire in a hearth. Its defining feature is not size but aim. Light with a target behaves differently from light with none — it can be kept alive in a small space, it is steady where the sun is periodic, and it is read as focus, selective warmth and quiet intensity.
Compared with 丙, the reading is often described as sharper. A lamp in a bright room is nothing; a lamp in a dark room is the only thing. Classical practice reads 丁 charts as sensitive to circumstance in exactly that way: the same chart reads very differently depending on whether the rest of it provides contrast or washes it out.
The ten gods, read from 丁
The ten gods are not ten things — they are five relations, each of which comes in two polarities, and the relation is always measured from the day master. With 丁 as the reference the five relations resolve as follows: 火 itself is the Peer, Wood generates 火 and is the Resource, Earth is what 火 produces and is the Output, Metal is what 火 controls and is the Wealth, and Water is what controls 火 and is the Officer.
The table below is produced by the engine from that rule alone — the element relation, multiplied by whether the two stems share a polarity. Nothing in it is memorised and nothing in it is interpreted. This is the reason a chart can be re-read by anyone: change the day master and all ten names change at once, in a way that is checkable rather than a matter of opinion. On the chart in the worked example below, 丁 is the day stem itself, so the four visible stems around it each carry one of these names.
What feeds 丁, and what spends it
A chart is not read by counting elements — it is read by what each element does to the day master. Wood (甲 乙) generates 火, so it is the Resource: what supplies 丁 without being asked. 丙 丁 is the Peer. Earth (戊 己) is what 火 produces, so it is the Output: energy that leaves as work, expression or craft. Metal (庚 辛) is what 火 controls, so it is the Wealth. Water (壬 癸) is what controls 火, so it is the Officer — the element that acts on 丁 and therefore carries the chart's pressure.
Five relations doubled by polarity gives the ten gods, and that is the whole structure. What it does not give you is a verdict on whether 丁 has enough support, because that judgement depends on how much you weight the month of birth, whether hidden stems count fully, and whether rootedness outranks raw count — and three competent practitioners can disagree. So we print the counts and the support/drain split, and leave the weighing to the reading rather than hiding a weighting model inside a score.
Where 丁 turns up in the branches
丁 appears inside three branches: 午, where it is the primary hidden stem, and 未 and 戌, where it is a secondary one. Those last two are transitional earth branches at the end of summer and autumn, which is why classical practice says a little fire survives inside them.
This matters more than it sounds. Four of the eight characters in a chart are branches, and each branch conceals between one and three stems, so a chart can hold 火 energy in a form that never appears on the surface. The list below is generated from the same fixed hidden-stem table the calculator uses — you can check it branch by branch.
The common misreading
The most common error is to read 丁 as "less fire" — a dimmer version of 丙. Polarity is not intensity. 丁 is read as the more concentrated of the two, and the classical claim is the opposite of instinct: a candle can be the decisive light in a room where the sun is only general illumination.
A worked example
Every page on this site that needs a worked example uses the same approach: a real birth moment, run through the engine at build time, with the numbers printed so you can reproduce them. This page's example is 1 February 1990, Taipei.
Input
- Date
- 1 February 1990
- Time
- 10:00
- Place
- Taipei, Taiwan
- Time zone
- Asia/Taipei
Nearest 节
Next: 立春1990-02-04 · 10:14
Year pillar 己巳 — this date is before 立春, which is what sets it.
Day master of this chart
丁 — Yin Fire
Day pillar 丁酉 · 纳音 山下火 · image the lamp
All four pillars, computed at build timeyear · month · day · hour
Year 年
己巳
大林木
Month 月
丁丑
涧下水
Day 日
丁酉
山下火
Hour 时
乙巳
覆灯火
- Wood113%
- Fireself450%
- Earth225%
- Metal113%
- Waterabsent
Surface tally 8 of 8 — and no Water at all. Support 5, drain 3, counted across the four stems and four branches and not weighted by season. A single absent element is a fact about this one chart, not a verdict on it.
Ten consecutive days, ten day masters
1 February 1990 gives 己巳 丁丑 丁酉 乙巳 — the day pillar is 丁酉, so the day master is 丁. It belongs to a run of ten consecutive dates, 30 January to 8 February 1990, which produce all ten day masters exactly once, because the day pillar advances one step per calendar day and ten steps cycle through all ten stems. That same run straddles the exact minute 立春 fell in 1990 (4 February, 10:14 local), so the earlier dates sit in the 己巳 year and the later ones in the 庚午 year — which also flips the luck-pillar direction, since direction follows the year stem's polarity. On this chart the surface tally is Wood 1 · Fire 4 · Earth 2 · Metal 1 · Water 0 — support 5, drain 3, and the luck pillars run backward from 丙子.
Engine v1.1.0 · lunar-javascript@1.7.7 · these four pillars and this tally reproduce exactly from the input above, in your browser or ours.
The full stem map, computed
These ten names are not a list to memorise — they are computed by one rule: the element relation between the two stems, multiplied by whether their polarities match. The table is produced by the engine from that rule, and it changes completely the moment the day master changes away from 丁.
Peer
Same element as the day master
- 丙劫财 · Rob Wealth
- 丁比肩 · Companion
Output
What the day master produces
- 戊伤官 · Hurting Officer
- 己食神 · Eating God
Wealth
What the day master controls
- 庚正财 · Direct Wealth
- 辛偏财 · Indirect Wealth
Officer
What controls the day master
- 壬正官 · Direct Officer
- 癸七杀 · Seven Killings
Resource
What produces the day master
- 甲正印 · Direct Seal
- 乙偏印 · Indirect Seal
丁 against itself is a Peer of the same polarity, so it is always Companion 比肩. The other nine stems divide across the five relations with two in each — which is why there are exactly ten names and never eleven.
The hidden-stem table, filtered to 丁
A stem does not have to appear on the surface of a chart to be present — every branch carries one to three hidden stems, and this is where the engine finds them. The list below is generated from the same fixed table the calculator uses.
- 午Horse · Wǔ火 · midsummerprimary hidden stem
- 未Goat · Wèi土 · late summersecondary hidden stem
- 戌Dog · Xū土 · late autumnsecondary hidden stem
午 carry it as the primary hidden stem; 未 戌 carry it as a lesser one. A lesser position is not a weaker claim on the element — position matters for weighting, and weighting is the step where published schools disagree.
The other nine day masters
Each stem has its own page, and they are read against each other rather than in isolation — 甲 against 乙, 丙 against 丁. Whichever one is yours, the comparison is usually where the meaning is.
Questions
- What does a Yin Fire day master mean?
- 丁 is fire at the yin pole: the lamp rather than the sun. The chart is read for focus and selective warmth — where attention is directed, and how it behaves when there is nothing to contrast against. It is a starting material for a reading, not a personality verdict.
- Why is 丁 called "the lamp"?
- Because the classical image captures aimed light: it can be carried, kept alive in a small space, and made steady. It also captures dependence on circumstance — a lamp matters in a dark room and is invisible in a bright one, which is the same kind of conditional statement classical practice makes about charts.
- Is a 丁 day master meant to be reserved?
- Not necessarily. The image describes how the chart’s fire behaves, not how a person talks at parties. Focused intensity can express itself as reserve or as single-mindedness; which one shows up is decided by the other seven characters and by the luck pillars, not by the stem alone.
- Where else can 丁 appear in my chart?
- As a stem in any other pillar, or hidden inside 午, 未 and 戌. When it is not the day master, it is named by its relation to the day master — 丁 seen from 庚 is a Direct Officer, from 壬 a Direct Wealth. The ten gods calculator names all of them for your own chart.
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BaziPattern provides AI-generated readings for entertainment and cultural exploration purposes only. Readings are not predictions, or medical, legal, or financial advice.