Unsure of Your Birth Time? Read This First

To cast a Zi Wei Dou Shu chart takes, in truth, only three things: the year, month, and day of birth; the hour of birth; and the sex. The first of these most people fill in at a stroke; only the cell for the hour tends to leave a person stalled, the pen hovering, slow to come down.

One has no birth certificate to hand; another remembers it was daytime but cannot say the hour; another is caught at the stroke of midnight, unsure whether to count the day before or the day after. Such hesitations are all quite ordinary, and no cause to hold back. This piece sets out, one matter at a time, the things to settle before casting a chart, so that you may place your birth details rightly, and then put your question with an easy mind.

Why the Hour Matters So Much

The first step in Zi Wei Dou Shu is establishing the Life Palace (命宮). And where does the Life Palace come from? Put simply, it is reckoned from the month of birth, then counted off according to the hour. This means: once the month is fixed, the hour is what decides which palace the Life Palace falls in. Shift the hour one place forward or back, and the Life Palace moves to a new seat.

And once the Life Palace moves, a single hair pulls the whole body along. The other palaces — Siblings, Spouse, Children, Wealth, Health, Travel, Friends, Career, Property, Well-being, Parents — all shift with it, and with them the seating of the main stars and the spread of the Four Transformations, the whole thing arranged anew.

This is why we say that a single hour’s difference is often two entirely different charts. Given the same year, month, and day, a person born in the Zi hour and one born in the Chou hour may show leanings of temperament and turns of fortune that diverge widely. The reason the hour asks for care lies just here: it is not some fine adjustment past the decimal point, but the very foundation of the whole chart. Move the foundation, and the building rises somewhere else entirely.

For just this reason, this step of setting down the birth time deserves a little extra thought. Rather than pass over it vaguely, before you put your question, turn over the records you have, and ask what can be asked. Better to spend a moment confirming the hour than to hold a chart set one place off and, having asked at length, receive the answer to another person’s life.

The Twelve Double-Hours, Against the Modern Clock

The ancients divided a day into twelve double-hours (十二時辰), each of two hours, named for an earthly branch. Set against today’s clock, they run as follows:

The Zi hour, 23:00–01:00; the Chou hour, 01:00–03:00; the Yin hour, 03:00–05:00; the Mao hour, 05:00–07:00; the Chen hour, 07:00–09:00; the Si hour, 09:00–11:00; the Wu hour, 11:00–13:00; the Wei hour, 13:00–15:00; the Shen hour, 15:00–17:00; the You hour, 17:00–19:00; the Xu hour, 19:00–21:00; and the Hai hour, 21:00–23:00.

To hold them in memory, fix a few anchor points first: the Zi hour is the dead of night, the Wu hour is high noon, the Mao hour is daybreak, the You hour is sundown. As long as you know roughly the hour of your birth, you can match it against this table and find the double-hour it belongs to. And if all you have is a hazy impression — just after dawn, say, or just past the midday meal — you can still frame a rough range, and narrow it down by degrees.

Early Zi Hour and Late Zi Hour: What Sets Them Apart

Of the twelve double-hours, the one most apt to give pause is the Zi hour. The Zi hour straddles the middle of the night — from 23:00 of the previous day to 01:00 of the next — cleft exactly in two by the stroke of midnight. Hence the division into early Zi hour and late Zi hour: the stretch from 23:00 to 00:00 is called the late Zi hour, also the night-Zi hour; the stretch from 00:00 to 01:00 is called the early Zi hour.

The difference between them is not only which comes first on the clock, but which day each belongs to. The mainstream practice is this: the early Zi hour, being past midnight, has already turned into the new day, and is reckoned by the new day; while the late Zi hour, before midnight, still belongs to the day before, and is reckoned by the day before. There is also a school that assigns the Zi hour whole to the following day, drawing no line between early and late. The lineages differ, and there is no single settled verdict; you need only know by which reckoning your own chart has been cast.

If you happen to have been born within these two hours about midnight, take particular care in casting the chart: first confirm whether the moment of birth fell before or after twelve, and only then decide how to enter the date. Fill this one cell wrong, and the whole chart may fall a day off — a thing not to be taken lightly.

What If You Truly Don’t Know the Exact Hour?

If the hour truly cannot be brought to mind, do not fret — there are more threads to follow than one might think.

The most reliable are records in black and white. A birth certificate usually notes the time of birth; if none is to hand, you may request the birth-registration records from the civil registration authority, or apply to the hospital of your birth for its medical and delivery records — these are mostly noted down to the minute.

Next is the memory of elders. Parents and grandparents often remember the scene of the time — whether they hurried to the hospital before daybreak, or set out only after the midday meal; whether it was the first bus of the early morning, or the hour when the lamps were lit at nightfall. Weigh these fragments against the table of double-hours above, and you can often narrow the range to within an hour or two.

And if you have asked after every thread and still land only somewhere among two or three adjacent double-hours, there remains one last method: the trial cast. Cast a chart for each possible hour, then take the great, settled events of your life — the turning points of your schooling, the timing of a marriage, the rise and fall of your fortunes — and hold them up against each chart to see which best fits the road you have walked. This is called, in the tradition, chart rectification (定盤).

Rectification takes patience, and an honest looking-back over your own past; it is no guess pulled from the air, but a reasoning from what has already come to pass toward the one door that fits most snugly. Get the door right, and the words spoken afterward can be spoken truly.

And if, for now, it cannot be settled, no matter. Begin with the hour you are most sure of, and sketch the broad outline; when memory grows clearer and records more complete, it is not too late to turn back and correct it. A chart is no seal fixed once and for all, but a mirror that can be brought into focus little by little, growing clearer the longer you look.

Lunar or Solar, and What About a Leap Month?

People often ask: to cast a chart, should one use the lunar calendar or the solar? The answer is that Zi Wei Dou Shu goes by the lunar calendar (農曆), also called the old calendar. Since the Life Palace is reckoned from the month of birth, that month is precisely the lunar month.

But you need not do the conversion by hand. Today’s chart-casting asks only that you enter the solar birthday you know well, and it converts that, of itself, into the corresponding lunar date. Simply fill it in from the solar date on your identity document, and you are the less likely to err.

The one thing to mind is the leap month. To keep step with the solar terms, the lunar calendar now and then gains an extra, leap month (閏月); if you happen to have been born in a leap month, be sure to mark it as such when you enter your details, so as not to confuse it with the ordinary month of the same name. Such a case is uncommon, but should you meet it, marking it clearly is all it takes.

True Solar Time: An Honest Word on One More View

There is one more view worth an honest mention: true solar time (真太陽時). The point is that the clock keeps a single standard time, while the real early or late of daylight shifts from place to place with the longitude of where one stands; the exacting hold that, before casting a chart, one ought to adjust the hour a little according to the longitude of the birthplace.

Opinions on this differ from school to school: some observe it faithfully, while others feel that within a region of no great breadth the gap is slight, and clock time will serve well enough. We will not weigh here which is right; we only remind you that such a thing exists. Should the gap between your birthplace and standard time happen to fall right about the border between two double-hours, you may wish to take it into account as well, and keep a quiet note of it in mind.