Learn · Fate · 14 min read · Updated September 2026

The Four Pillars

The reading a practitioner most often attaches to a house is not feng shui but astrology, and the two share every part. The stems and branches that name the years, the months, the days and the hours; the chart of eight characters, its day master and the element it is read as lacking; how that element becomes a colour on a wall; what the tradition’s own personal method, the kua, does instead; and what the research on birth years and the dragon’s children actually shows.

Oriented N 000°

Water

Fig. 01 Characters in ink. A chart is eight of them in four pairs, read from the right.

Ask a practitioner to read a house and many will begin by asking for a birth date and an hour, and produce, before they have looked at a wall, a chart of eight characters. The chart is the Four Pillars, ba zi, and it is not feng shui. It is Chinese astrology, an art with its own classics and its own history, and it is built from the same stems, branches and elements as the compass, which is why the two are so easily run together and so often sold as one. This essay gives the cycles, the chart and the reading, says how the reading becomes advice about a house, sets the tradition’s own personal method beside it, and reports what the research has found when it has tested a birth year against a life.

Two cycles

Fig. 01 The two cycles the calendar counts with, as the almanac and the Four Pillars use them. The ten heavenly stems run in five pairs, a yang and a yin of each element in the generating order, Wood, Fire, Earth, Metal, Water. The twelve earthly branches carry the animals, an element each, the two hours of the day each rules, from the Rat at midnight, and the month each names, from the Tiger at the start of spring. A stem and a branch together make one of sixty pairs, and the sixty run in a cycle over the years, the months, the days and the hours; a person’s four pillars are the four pairs current at their birth. The cells are tinted by element, and the tints are the site’s five. The stems and branches are older than any use of them: the sixty-day cycle is on the Shang oracle bones of the thirteenth century BC, the animals were attached to the branches by the Han, and the elements later still. The hours are the traditional double hours; a chart cast for a modern clock time must first be converted to local solar time.

The calendar counts with two cycles, and everything in the Four Pillars is made of them. The ten heavenly stems, tian gan, run in five pairs, a yang and a yin of each element in the generating order: Jia and Yi are Wood, Bing and Ding Fire, Wu and Ji Earth, Geng and Xin Metal, Ren and Gui Water. The twelve earthly branches, di zhi, are the cycle the animals ride on: the Rat is Zi, the Ox Chou, the Tiger Yin and so on round to the Pig, and each branch carries an element, rules two hours of the day, from the Rat at midnight, and names a month, from the Tiger at the start of spring. A stem and a branch together make one of sixty pairs, since ten and twelve return to their start together only at sixty, and the sixty run over the years, the months, the days and the hours without a break. The cycle is older than every use anyone has made of it. Keightley’s study of the Shang oracle bones finds the sixty-day cycle already the ordinary way of naming a day in the thirteenth century BC; the years were counted by it from the Han, the animals were attached to the branches in the same period, and the elements were fitted to both by the correlative cosmology Needham describes, which by the Song had given every character in the calendar an element to belong to. The almanac prints the day’s pair at the head of every column, and the choosing a day essay reads it there.

The chart

Fig. 02 A Four Pillars chart as a practitioner lays it out, for an illustrative birth: a yang Fire day in a Rabbit month of an Ox year, at the Rat hour. The four columns are the hour, the day, the month and the year, read from the right as the Chinese page reads; each is a stem over a branch, the pair current at the birth, and the small row beneath gives the stems the tradition reads as hidden inside each branch. The day’s stem, Bing, is the day master, the character that stands for the person, and everything else in the chart is read as its relations: the Wood of the month and the year feeds a Fire day master, the Earth of the hour and the year is what it produces, and the Water of the hour is what controls it. The count of the five elements under the chart is what a practitioner looks at first, and a chart with three Wood, three Earth and no Metal is read as needing what it lacks, which is where the advice about colours and directions comes from. The chart is made up to be consistent, not cast for a real person; the hour’s stem follows the day’s and the month’s follows the year’s by the tables in any almanac. The hidden stems are the standard set; the count includes the visible stems and branches only, as the simpler manuals do.

A person’s four pillars are the four pairs current at their birth: the pair of the year, of the month, of the day and of the hour, eight characters in four columns, which is what the name means. The method of reading them is attributed to Xu Ziping of the tenth century, and the change he is credited with is the one that made the art: the older readers, Li Xuzhong of the Tang among them, had taken the year’s stem as the person, and Xu took the day’s, the day master, ri zhu, and read the other seven characters as its relations. Smith’s history of Chinese divination gives the lineage and the vast literature that followed; Ho Peng Yoke sets out the method beside the other calculating arts of fate, the Taiyi, the Qimen and the Liuren, as a historian of science reads them, and finds the Four Pillars the plainest of them and the one that survived.

The reading is the Five Elements applied to a person. The day master is an element with a polarity, a yang Fire or a yin Metal; each other character is one of five relations to it, by the cycles the Five Elements essay draws: the same element, which the tradition calls a companion; the element it produces, its output; the element it controls, which it calls wealth; the element that controls it, which it calls power or authority; and the element that produces it, its resource. A practitioner counts the elements in the chart, weighs the day master by its season, since a Fire born in the Rabbit month of spring is fed by Wood and strong, and a Fire born in the Rat month of winter is quenched, and names the element the chart most needs for balance, the useful god, yong shen. Ten-year luck pillars, stepped off from the month pillar, are then read against the chart for the course of a life. The art is intricate, the manuals disagree at every step after the first, and a competent reader takes years to make; the site describes it and does not practise it.

From the chart to the house

The chart reaches the house through the useful god. A person read as short of Water is told to sleep with the head to the north, to use blue and black, to keep a fountain, to work facing the direction Water rules; a person short of Metal is given white, round shapes and the west; and the advice arrives as feng shui because it is about a room. It is not classical feng shui. The Book of Burial casts no charts and the yang-house manuals of the Ming and Qing use, at most, the year of birth; the marriage of the Four Pillars to the house is the work of the Hong Kong and Malaysian schools of the late twentieth century, whose manuals Too and Wong represent in English, and it is a genuine part of the modern practice without being a part of the old one. The tradition’s own personal method inside feng shui is the Eight Mansions kua, a single number from the year of birth that sorts people into two groups and gives each its four good directions; it is cruder than the Four Pillars and it is the one the compass classics actually use. A reader who wants a personal reading from the tradition proper has the kua. A reader who wants the Four Pillars is buying astrology, which is a fair thing to buy if it is bought as itself.

Fig. 03 How a birth chart becomes advice about a room, in three steps, for the chart the page works. The eight characters are tallied by element, and the worked chart has three Wood, three Earth, one Fire, one Water and no Metal. The practitioner names the useful god, the element the chart most needs for balance, which here is Metal, with Water to carry it; the naming is the skill of the art and two practitioners can name differently. Then the useful god is turned into the house: Metal is white, round shapes and the west, Water is blue and black, the north and a fountain, and the person is told to sleep with the head to the north, to keep a bowl of water and to work facing west. The third panel is the room that results, and the objection the design note raises is drawn in it: the wall is shared and the chart is not, and a household of four has four charts and one wall. The count and the chart are the page’s worked example; Too 1996 and Wong 1996 for the useful-god advice as the Hong Kong and Malaysian schools give it. The method is astrology applied to a room, a genuine part of the modern practice and no part of the classical one.

The drawing follows the worked chart through the three steps by which it reaches a wall. The count comes first, the eight characters tallied by element, and the chart above has three Wood, three Earth, one Fire, one Water and no Metal. The useful god comes second, and it is the one act of judgement in the method: a practitioner reads the day master, a yang Fire, against the count and names the element the chart most needs, which here is Metal, with Water to carry it, and another practitioner reading the same chart may weigh the season and name differently. The room comes third, mechanically, once the god is named: Metal is white, round shapes and the west, Water is blue, black, the north and a fountain, and the person is told to sleep with the head north, to keep a bowl of water and to work facing west. The third panel draws what the design note objects to. The advice is about a person and the wall is about a household, and four people in a flat have four counts, four useful gods and one wall, which is why the site sends the colours back to the colour guide, where they are chosen by the room and its light and survive a family.

Evidence · Birth years, tested

Astrology as a claim about persons has been tested and has failed the tests; Carlson’s double-blind trial in Nature in 1985, in which astrologers could not match charts to personality profiles above chance, is the standard reference for the Western art, and no equivalent trial of the Four Pillars has done better. What the Chinese birth year does affect is the parents. Goodkind found births in Chinese populations rising sharply in Dragon years, as families timed conceptions to the animal; Mocan and Yu then found that the Dragon children of one such cohort did better in school and in the national examinations than the children of the years either side, not because the year did anything but because their parents, believing it would, invested more in them, and the effect vanished once the parents’ expectations were held constant. The chart’s power, where it has been measured, is the power of what a family believes about a child, and that is real and not small.

Reading a chart, in order

Convert the time. Birth to local solar time first; the Rat’s hour begins at eleven at night, and a half hour can change the day.
Find the four pairs. The year, the month, the day and the hour, from an almanac or a table; the month changes at the solar term, not at the new moon.
Take the day stem as yourself. Its element and polarity are the day master; the other seven characters are its relations.
Count the elements. Stems and branches together; what is absent or single is what the reading will name as the useful god.
Weigh the season. The month branch feeds or quenches the day master, and a chart is strong or weak before it is anything else.
Treat the useful god as a suggestion. A colour for a bedroom or a desk, for the person whose chart it is; not a scheme for the house.
Keep the kua for the house. The Eight Mansions directions are the tradition’s own personal reading, and they need only the year.