TL;DR: The Hour Pillar is one of the four pillars in BaZi, representing the birth hour, reflecting late-life fortune, children, and later relationships. It is determined by the Day Stem and the 12 Earthly Branches system.
What is the Hour Pillar in Bát Tự (Four Pillars)?
Bát Tự (BaZi, the Four Pillars) is a system of destiny interpretation based on the hour, day, month and year of birth according to the Can Chi (Heavenly Stems and Earthly Branches) calendar. Each element is expressed as a Pillar made up of a Heavenly Stem (above) and an Earthly Branch (below). The four Pillars in order are: the Year Pillar, the Month Pillar, the Day Pillar and the Hour Pillar. The Hour Pillar, as the name suggests, is determined from a person's exact hour of birth and is the last pillar in the chart.
But to understand where the Hour Pillar really sits within the whole chain of reasoning in this discipline, one has to go through the four steps that every chart must pass: determining the month command, measuring the strength or weakness of the day master, setting the structure, and then choosing the useful god. The Hour Pillar only has meaning once it is placed within that chain. Anyone who reads the Hour Pillar before going through this whole chain is reading it in isolation.
Is the Hour Pillar favorable or unfavorable when the self is strong or weak?
The Hour Pillar is the branch and stem of the birth hour, where the chart closes. When the self is strong, it often plays the role of draining qi or controlling, so it easily becomes favorable, unless it adds strength to the already flourishing element. When the self is weak, it becomes favorable if it generates and supports or shares qi with the day master, and becomes unfavorable if it falls into an element that drains. To know whether it becomes the 用神, one must place it beside the 月令, flourishing or declining, chart structure, and then examine it through 扶抑, 通关, 调候, 病药. The Hour Pillar is also the place where the 从格 situation is easily overturned, because a small root here can break the following trend. Read the full article at What is the 'Useful God' (Yong Shen) in BaZi (Four Pillars)? and What is Strong Self (Thân Vượng) and Weak Self (Thân Nhược) in BaZi (Four Pillars).
So where does the Hour Pillar sit in this chain?
The Hour Pillar is an input to the step of measuring strength or weakness, and the output of the interpretation step once the useful god has been chosen.
On the input side: the branch of the Hour Pillar is one of the three criteria for gaining the ground. If the day master has a root in the branch of the Hour Pillar, it is markedly stronger than when it has no root. The Stem of the Hour Pillar also takes part in gaining the configuration, and may be the revealing stem that determines the structure if the month command does not reveal.
On the output side: only after the useful god, favourable god and unfavourable god have been chosen does one return to read the Hour Pillar. Which element the Hour Pillar carries, whether that element is a favourable god or an unfavourable god, and how it interacts with the other pillars, and only from that does one infer the later fortune and the relationship with children. Reading the Hour Pillar before choosing the useful god is reading it in isolation, and that is exactly where shallow articles go wrong.
One more thing that shallow articles often omit needs to be said: the branch of the Hour Pillar may be the only place still holding a root for the day master in charts near the following threshold. In that case, whether the Hour Pillar has a root decides whether the chart is interpreted by support and restrain or by following, that is, it decides two opposite directions of reading. The same Hour Pillar branch is a minor detail in one chart and the turning point of the entire reasoning in another.
What is the role of the Hour Pillar in interpretation?
In Bát Tự, each Pillar carries its own layer of meaning:
- Year Pillar: represents ancestors, lineage, and the early period of life (before age 16).
- Month Pillar: represents parents, career, and youth (from 16 to 32).
- Day Pillar: represents oneself and one's spouse, and the middle-age period (from 32 to 48).
- Hour Pillar: represents children, students, subordinates, as well as later fortune (from 48 onwards) and late relationships.
The Hour Pillar is regarded as a factor that partly determines the fortune of the final years of life, one's career after retirement, and the relationship with children. If the Hour Pillar is good, the person may have a favourable later life, filial and successful children. Conversely, if the Hour Pillar is bad, there may be obstacles in late relationships or difficulties for the children.
It must be emphasised: good or bad here is not a fixed property of the Hour Pillar, but the result of comparing its element with the useful god already chosen. The same Hour Pillar may be good for one chart and disadvantageous for another. This is why one cannot look up a table of "which element in the Hour Pillar is good" and then draw a conclusion.
How is the Hour Pillar determined?
The Hour Pillar is made up of the Hour Heavenly Stem and the Hour Earthly Branch.
1. Determining the Hour Earthly Branch
The Hour Earthly Branch is determined simply from the birth time slot according to the system of the 12 zodiac animals (Tý, Sửu, Dần, Mão, Thìn, Tỵ, Ngọ, Mùi, Thân, Dậu, Tuất, Hợi). Each animal corresponds to 2 clock hours:
| Time slot | Earthly Branch |
|---|---|
| 23h–1h | Tý |
| 1h–3h | Sửu |
| 3h–5h | Dần |
| 5h–7h | Mão |
| 7h–9h | Thìn |
| 9h–11h | Tỵ |
| 11h–13h | Ngọ |
| 13h–15h | Mùi |
| 15h–17h | Thân |
| 17h–19h | Dậu |
| 19h–21h | Tuất |
| 21h–23h | Hợi |
2. Determining the Hour Heavenly Stem
According to the rules of the Can Chi calendar, the Heavenly Stem of the Hour Pillar depends on the Heavenly Stem of the Day Pillar (the day stem). The following lookup table can be used (based on the formula for calculating Can Chi in calendrical science):
| Day stem | Tý hour stem | Sửu hour stem | Dần hour stem | ... |
|---|---|---|---|---|
| Giáp, Kỷ | Giáp | Ất | Bính | ... |
| Ất, Canh | Bính | Đinh | Mậu | ... |
| Bính, Tân | Mậu | Kỷ | Canh | ... |
| Đinh, Nhâm | Canh | Tân | Nhâm | ... |
| Mậu, Quý | Nhâm | Quý | Giáp | ... |
For example: if a person is born on a day whose Stem is Giáp, then the Tý hour will have the Stem Giáp, the Sửu hour will be Ất, the Dần hour will be Bính, and so on. This calculation is based on the cycle of the 10 Stems and 12 Branches, forming a 60-day cycle, as explained in the calendrical Can Chi problems.
What is the detailed interpretive meaning of the Hour Pillar?
In Bát Tự practice, the Hour Pillar is analysed through several aspects:
- The five elements of the Hour Pillar: Examining the generating and controlling relationships between the Stem and Branch within the Hour Pillar, as well as with the other Pillars. For example, an Hour Pillar with a strong Fire element may support or clash with the chart owner.
- The ten gods of the Hour Pillar: Converting the Hour Stem into a ten god (such as Direct Wealth, Indirect Seal, Eating God...) based on its relationship with the Day Stem. This shows what kind of relationship the Hour Pillar represents in a life (children, wealth, benefactors...).
- Interaction with the other Pillars: The Hour Pillar is usually regarded as the residence of the Tử Tức cung (the children's palace). If the Hour Pillar clashes with the Day Pillar, it may hint at a relationship between parent and child that is not harmonious.
- Major periods and later fortune: In interpretation, the Hour Pillar is also used to infer fortune after age 50, the period when a person often looks back on life and enjoys the results.
What was said above must be repeated to avoid misunderstanding: these four aspects can only be read once the useful god has been chosen. If one reads the ten gods of the Hour Pillar without knowing whether that element is favourable or unfavourable, the conversion only shows what role the Hour Pillar plays, not whether that role is good or bad for the chart.
Points to note when interpreting the Hour Pillar
- The birth hour must be accurate: A deviation in the birth hour can change the entire Hour Pillar, so determining the birth hour accurately is of the utmost importance.
- The Tý hour (23h–1h): There is debate over whether the Tý hour begins at 23h or at 0h. Some schools count the new day as beginning at 23h, others from 0h. This can affect the day stem and therefore affect the Hour Pillar.
- Summer time births (DST): If born in a period with daylight saving time rules, it is necessary to convert back to actual solar time for the calculation.
- It should not be absolutised: Bát Tự is a traditional system of interpretation, not a tool for certain prediction. Personal effort and life circumstances still play an important role.
