By Arcadia ·
A Bazi chart is fixed at birth, yet the tradition reads it as something that unfolds. Two mechanisms carry it through time and through its own internal tensions: the ten-year luck pillars, which set the chart moving, and the relations between the earthly branches, which describe how its parts pull on one another. This article explains both, then sets Bazi beside the I Ching, the Chinese system it is most often confused with, and closes with a note on what the method can and cannot claim.
大運, da yun, is the sequence of ten-year periods through which a chart is read. It is not a separate forecast bolted onto the chart. It is the month pillar continuing, stepping one term along the sixty-term cycle every ten years, so that the periods of a life are literally the months that would have followed (or preceded) the one in which the person was born.
Three rules build the sequence, and only the first is regularly got wrong.
The direction is the polarity of the year stem crossed with the person’s sex. A yang year stem with a male, or a yin year stem with a female, runs forward through the cycle; the other two combinations run backward. Written as four cases it is something to memorise. Written as a single question, whether the polarity of the year agrees with the sex of the person, it is something to understand.
The starting age is the distance from the birth to a solar term. Going forward, it is the distance to the next 節, the next “joint” term that opens a Bazi month. Going backward, it is the distance back to the joint that opened the birth month. Count that distance in days and divide by three, because in this reckoning three days of the Sun stand for one year of life. One day is therefore four months, and one hour is five days. A person born two days before 立冬, the Start of Winter, running forward, begins the first luck pillar at about eight months old rather than at a rounded number of years.
The distance should be measured against the real instants of the solar terms, taken from an ephemeris, not against a nominal fifteen-day month. A simple check keeps the arithmetic honest: from any birth inside a month, the days forward to the next joint plus the days back to the last one must add up to the length of that month.
Then the pillars run, one every ten years from the starting age. Each is a stem over a branch, and each stem is one of the ten gods to the day master, so a decade can be described as, for instance, a period of Direct Officer over a Water branch. Many schools read the stem of a luck pillar as weighing more in its first five years and the branch in its last five, though not all agree on this.
The annual pillar, 流年, is the stem and branch of the current year. It is never read on its own. It is read through whichever ten-year pillar is running at the time, and both are read against the natal chart. The same year can therefore mean quite different things for two people, or for one person in two different decades.
The stems relate to each other through the five phases. The branches have, in addition, a set of relations of their own. Lay the twelve branches round a clock face, 子 at the top, and most of those relations stop being a table to memorise and become geometry.
冲, the clash, is the branch directly opposite: six steps away. There are six pairs and no exceptions: 子 and 午, 丑 and 未, 寅 and 申, 卯 and 酉, 辰 and 戌, 巳 and 亥. The meaning is written into the geometry. 子 and 午 are midnight and noon, midwinter and midsummer; 卯 and 酉 are the two equinoxes. A clash is read as something shaken loose rather than something destroyed: movement, change of place, a break in what was settled.
三合, the three harmonies, are the equilateral triangles on the clock: any branch, plus four, plus eight. There are four of them, and each runs from where a phase is born, through where it peaks, to where it is stored:
All three branches present is the strongest single statement a set of branches can make, and it can tilt the balance of a whole chart toward the phase of the triad. Two out of three is a half-combination: weaker, and different in character. It should not be reported as a full triad.
Alongside the triads stand the directional or seasonal combinations (三會), the three branches of one season taken together, such as 寅 卯 辰 for the Wood of spring.
六合, the six unions, and 害, the six harms, are pairs defined by a simple rule. Number the branches from 子 as 0 to 亥 as 11. The unions are the pairs whose numbers add up to 1 (counting round the clock, so that 13 counts as 1): 子 with 丑, 寅 with 亥, 卯 with 戌, 辰 with 酉, 巳 with 申, and 午 with 未. The harms are the pairs that add up to 7: 子 with 未, 丑 with 午, 寅 with 巳, 卯 with 辰, 申 with 亥, and 酉 with 戌.
The harms are the neater of the two, because each harm is the clash of one’s union partner. 子 unites with 丑, and 未 clashes 丑, so 子 and 未 harm each other: a third party breaking up something that was settled. The name describes the mechanism.
刑, the punishments, are the exception, and it is worth being straight about it. The groups 寅 巳 申, 丑 戌 未, the pair 子 卯, and the four branches that punish themselves (辰, 午, 酉 and 亥) are received from the tradition. Nothing in the arrangement of the twelve generates them, and the explanations offered in the literature are after the fact. A student can derive the clash, the triads, the unions and the harms from the clock face; the punishments have to be learned as a list.
The two are confused constantly, and the confusion is understandable. Both are Chinese, both work with yin and yang, both use the five phases somewhere, and both end up on the same shelf labelled “Chinese divination”. They are not versions of each other.
The I Ching is consulted. You have a question, you cast coins or yarrow stalks, and you receive one of sixty-four hexagrams with its lines and its changes: an answer to a situation, at a moment, arrived at by an act of asking. It says nothing until it is asked, and it says something different the next time.
Bazi is computed. There is no casting and no question. A birth moment produces eight characters and no others; the chart is the same today as it was on the day of birth and will be the same in forty years. What changes is only which luck pillar and which annual pillar are being read against it.
So the two answer different kinds of question. One is about a decision in front of you. The other is about a structure you are standing inside. A practitioner may well use both, and many do, but reading a Bazi chart as though it were an oracle, asking it what to do about next Thursday, is a category error. So is expecting the I Ching to describe a temperament.
What they genuinely share is the cosmology underneath: yin and yang as complementary rather than opposed, the correspondences between trigrams, directions and phases, and a view of time as something with quality rather than mere extent. James Legge’s translation of the Yi King (1882), the standard nineteenth-century English text, is where most Western readers first met that framework.
Classical Bazi is a large literature, and it does not restrict itself. There are branches of it that read health from the balance of the phases, that read a marriage from the day branch, that put a figure on wealth and a season on death. Practitioners have done this for centuries, and there is no point in pretending the material does not exist.
But a reading of that kind was always a conversation. It depended on who was asking, what they already knew, what they were able to hear, and a great many things visible across a table and invisible in eight characters. Two people with the same chart live different lives; the tradition itself admits this when it insists on reading luck pillars, annual pillars, and the circumstances of family and place alongside the natal pillars. A sentence about someone’s health or marriage, produced mechanically from a birth date and delivered without context, is not the tradition being respected. It is the tradition flattened into something it never was.
The useful line to draw is between structure and verdict. The structure is objective in the sense that anyone with the same rules will compute it the same way: the eight characters, the phases and how they were weighed, what each god is and what its reverse is, which branches meet which, which pillar is running now. The verdict is a judgement, made within a body of doctrine that has a history and a range of opinion inside it. The same holds for comparing two charts. The relations between their branches can be shown; turning those relations into a decision about another person’s life is something the tradition’s compatibility material has too often been used for, and something the eight characters alone cannot justify.
Two practical habits follow. Where the schools disagree, on the boundary of the day at 23:00 or at midnight, on true solar time or zone time, on the weighting of hidden stems, the choice should be stated rather than made silently. And where a number is a judgement rather than a measurement, as the strength of the day master is, the arithmetic behind it should be visible, so that the reader can see what it was built from and decide what to think of it.
A practical guide to consulting the I Ching: framing a good question, casting with coins or yarrow, finding changing lines, reading the Judgment and the Image, and reading change rather than fate.
An introduction to the Book of Changes: where it comes from, how yin and yang lines build eight trigrams and sixty-four hexagrams, and why the King Wen order matters.
How Bazi reads a chart: the two cycles of the five phases, the strength of the day master in its season, the useful element, and the ten gods as a five-by-two grid.
Four Pillars of Destiny
For the four pillars, the day master, the balance of the five elements, and the ten-year luck cycles.
