Notes · No. 1
What the Four Pillars Actually Are
A birth moment is cut into four slices: year, month, day, hour. Each slice takes one Heavenly Stem and one Earthly Branch. Four slices, eight characters — that is what a bazi chart is, and the four columns are the four pillars.
They are not four equal labels. The month pillar fixes the season and sets the climate of the whole chart. The day stem stands for the person, and every other judgement is measured against it.
The year pillar: where you start from
The year pillar is a pair of one stem and one branch, traditionally read as ancestry, family background and early childhood. It describes the hand you were dealt — the era, the region, the household. None of it was your choice.
It is easy to over-read. Assigning "early years" to the year pillar is a division of labour among the four columns, not a claim that everything before your sixteenth birthday is written there. Any single pillar read in isolation will mislead; they only mean something together.
The month pillar: the season, and the climate of the chart
The month pillar carries the most weight of the four. Its branch — the month command — marks where the sun stood: the start of spring, the awakening of insects, the clear and bright, and so on through the year.
Being born in deep winter or high summer sets the temperature and humidity of the entire chart. Take Wood as an example. Wood born in the first lunar month of spring is a shoot about to unfurl: it wants Fire to warm it and dislikes excess Water. Wood born in early autumn is foliage about to be cut: it wants Water to soften it and dislikes more Metal. Same element, opposite needs — and the difference comes entirely from the month.
Why the year and month turn at solar terms, not at new year
This is where most beginners lose their footing. The stem-and-branch year and month are divided by solar terms, not by the first day of the first lunar month.
Born before the Beginning of Spring, and your year pillar still belongs to the previous year. The month pillar turns at the twelve "jie" — Beginning of Spring, Awakening of Insects, Clear and Bright, Beginning of Summer, Grain in Ear, Minor Heat, Beginning of Autumn, White Dew, Cold Dew, Beginning of Winter, Major Snow, Minor Cold — not at each lunar month's first day.
A concrete case: someone born on 4 February, in a year when the Beginning of Spring falls late on that same day. Born a few hours earlier, and their year pillar belongs to the previous year, while the month is still the last month of winter rather than the first of spring. Feeding a lunar birthday into a chart calculator shifts the year pillar by a full column, and the Ten Gods and luck pillars move with it.
| Month branch | Solar term begins | Approximate date |
|---|---|---|
| Yin | Beginning of Spring | around 4 February |
| Mao | Awakening of Insects | around 6 March |
| Chen | Clear and Bright | around 5 April |
| Si | Beginning of Summer | around 6 May |
| Wu | Grain in Ear | around 6 June |
| Wei | Minor Heat | around 7 July |
| Shen | Beginning of Autumn | around 8 August |
| You | White Dew | around 8 September |
| Xu | Cold Dew | around 8 October |
| Hai | Beginning of Winter | around 7 November |
| Zi | Major Snow | around 7 December |
| Chou | Minor Cold | around 6 January |
The day pillar: you, and the marriage palace
The stem of the day pillar is the day master — the person the chart is about. Every relationship in the chart (what supports me, what I produce, what controls me, what I control) is calculated outward from this one character.
The branch of the day pillar is the marriage palace, traditionally tied to a spouse and to intimate partnerships. Whether that branch supports, drains or clashes with the day stem is the usual basis for discussing how someone behaves inside a close relationship.
The hour pillar: children and later life
The hour pillar covers children, subordinates, later life, and often the side of a person they do not put on display.
Hours run in two-hour blocks: the rat hour from 23:00 to 01:00, the ox hour from 01:00 to 03:00, and so on. Boundaries matter. People born around 23:00 may end up with different day pillars, because schools disagree on whether the day turns at the start of the rat hour or at midnight — check which convention your calculator follows.
There is a further technical point. When the longitude of the birthplace differs from the standard time zone, a rigorous reading corrects to local solar time. In western China that correction can reach one or two hours — enough to push the hour pillar across a boundary.
Two things beyond the four pillars
A complete chart usually carries luck pillars and annual pillars alongside the four.
Luck pillars are ten-year columns beginning from the month pillar, running forward or backward depending on the polarity of the year stem and the person's sex. Annual pillars are simply the stem and branch of each passing year. The four pillars describe structure; luck and annual pillars describe time. Structure says what tends to happen. Time says when.
Neither works alone. Without the four pillars you cannot say who a period favours. Without the luck pillars you cannot say when anything arrives.
Questions
Are the four pillars and a bazi chart the same thing?
Yes. Four pillars hold eight characters — four stems and four branches — which is why it is called bazi, literally "eight characters". "Four pillars" names the columns; "bazi" names the count.
Can I get a chart without knowing my birth hour?
Yes, but you are left with three pillars and six characters. Anything read from the hour pillar — children, later life — becomes unavailable, and some structural judgements turn uncertain. Check a birth certificate or ask family before giving up on the hour.
Should I use my lunar or my solar birth date?
Either, as long as the calculator knows which one it received. The year and month pillars are actually determined by solar terms, not by the lunar calendar, so entering a lunar date as if it were solar will always produce a wrong chart.
Do two people born at the same moment share a chart?
Their four pillars are identical. But sex determines whether the luck pillars run forward or backward and at what age they start, and the longitude of the birthplace shifts local solar time, which can move the hour pillar. The four pillars describe structural tendency, not specific events.