A Bazi chart never changes. The four pillars are fixed at birth, and What Is Bazi has so far read a static chart: eight characters, one Day Master, ten relation labels. That is exactly where a beginner gets stuck next — if the chart is fixed for life, where does timing come from? Why one smooth decade and one hard one? The moving parts that answer this are the luck pillars: da yun (大运), the ten-year cycle, and liu nian (流年), the year itself.
What are luck pillars in Bazi?#
English-language Bazi writing gathers both layers under the name luck pillars (also “luck cycles”). Da yun (大运) is one stem-branch pair per ten years; liu nian (流年) is the stem-branch pair of the current year. A chart is usually given eight to ten steps of da yun, which carries the reading across eighty to a hundred years.
The idea worth fixing first, because it organizes everything below: the luck pillars are not a second system. They are simply more stems and branches, generated by rule from the natal chart, and read by the same method as the natal chart — each incoming character tested against the chart’s favorable and unfavorable elements. The Qing-dynasty masterwork Ziping Zhenquan (《子平真诠》) says as much in its essay on reading luck cycles, Lun Xing Yun (论行运): reading luck and reading the chart are one method, not two — an incoming pillar is simply taken and matched against the chart’s favorable and unfavorable elements; there is no separate rulebook for it.
So hold this picture: the natal chart is a base map, and the luck pillars are the roads laid over it as time moves forward.
Da Yun: the ten-year cycle#
One step of da yun is ten years, one stem-branch pair per step. The ladder is counted from the month pillar — and the reason is worth knowing rather than memorizing. The month pillar carries the yueling (月令, “month command”), the position What Is Bazi identified as the chart’s climate, the strongest single voice in judging strength. A device meant to model time moving forward starts from the position that fixes the chart’s season, then steps along the stem-branch cycle — one pair every ten years.
One habit of speech deserves a caveat before it hardens into doctrine: “the first five years go with the stem, the last five with the branch.” That is one school’s saying, not a consensus — Ziping Zhenquan itself argues for reading the step’s stem and branch as a single unit — and a beginner loses nothing by treating each ten-year step whole.
Forward or reverse: the yang-man, yin-woman rule#
Whether the steps run forward or backward through the cycle is fixed by two things at once: the polarity of the year stem and the native’s sex.
| Year stem | A man | A woman |
|---|---|---|
| Yang (甲 丙 戊 庚 壬) | forward | backward |
| Yin (乙 丁 己 辛 癸) | backward | forward |
Forward means counting the stem-branch cycle onward from the month pillar; backward means counting it back. Take a 丙寅 month pillar: the first step forward is 丁卯, the first step backward is 乙丑 — and the whole ladder follows from that first step, one pair per decade.
The starting age: three days count as one year#
Da yun does not begin at birth. The first step starts at the starting age (qi yun 起运), computed from the distance between the birth moment and the nearest jie (节) term of the solar cycle:
- Forward cast — count from birth forward to the next jie term (Lichun, Jingzhe, and so on — the “jie” terms, not the “qi” 气 terms; the distinction is laid out under solar terms).
- Backward cast — count from birth back to the previous jie.
- Divide the days by three. The quotient is the starting age.
The conversion runs on three fixed tiers:
| Elapsed time | Luck-cycle time |
|---|---|
| 3 days | 1 year |
| 1 day | 4 months |
| one shichen (2 hours) | 10 days |
A birth ten days before the next jie thus starts its first da yun at age 3 years 4 months, and changes steps every ten years from there.
The ratio itself is not arbitrary, and knowing where it comes from saves the whole table: one jie-delimited month runs about 30 days, and one step of da yun runs 10 years — 30 ÷ 10 = 3, so three days of calendar time are read as one year of luck-cycle time. Da yun is, in effect, the solar-term month stretched by a fixed ratio into a ten-year unit.
A fairness note: schools differ on the fine points of this arithmetic — some round to whole days, some compute to the hour, some correct the term’s moment by true solar time. The Bazi Calculator offers the common options, so the same birth data can be compared across conventions.
Liu Nian and Liu Yue: the annual and monthly layers#
Liu nian is the stem-branch pair of the current calendar year — 2026 is a 丙午 year, so 丙午 is everyone’s liu nian this year. The incoming pair is identical for everybody; what differs is the chart it lands in, since the same 丙午 takes one ten-god label in one chart and another in the next.
The layers nest rather than sit side by side:
| Layer | Period | What it covers |
|---|---|---|
| Da yun | ten years | the climate of a life stage |
| Liu nian | one year | the year’s actual texture |
| Liu yue (流月) | one month | the twelve months inside a year |
The same liu nian reads differently inside different da yun — that is the whole point of the nesting. The Bazi Calculator is built on this ladder: open one da yun and the year row reloads with that decade’s ten years; click a year and its twelve months unfold.
How to read a luck pillar against the chart#
Casting the pillars is arithmetic; reading them is the craft. The yardstick comes first: the chart’s favorable and unfavorable elements, fixed by the Day Master’s strength — a strong Day Master is helped by being checked and drained, a weak one by being supported. Until that judgment is fixed, no luck pillar can be called good or bad; once it is fixed, every incoming character has a measure to be held against.
Three checks, in practice:
- Label the incoming stems and branches as ten gods. The ten gods grid applies to luck pillars exactly as to natal ones — and the same correction carries over: a label is a relation, not a verdict. A qisha (七杀) year is pressure on a weak Day Master and useful discipline on a strong one.
- Watch the branches. Clashes, combinations, punishments and harms between the incoming branch and the natal branches tend to move a chart more visibly than the stem’s label does. And a clash is not automatically bad — in the traditional reading, a clash that breaks open a branch holding an unfavorable element unlocks the chart rather than damaging it.
- Watch da yun and liu nian against each other. The two layers interact on their own — same stems, same branches, generating and overcoming. The combination watched most closely is sui yun bing lin (岁运并临), a year whose pair exactly repeats the running da yun’s pair, read as a year of unusual change.
A four-step reading order#
For a beginner the order matters more than any single rule:
- Fix the yardstick. Judge the Day Master’s strength and settle the favorable elements first — reading luck before that is the most common error in the whole art.
- Label the step. Convert the da yun’s stem and branch to ten-god relations; favorable gods read as support, unfavorable ones as drag.
- Check the branches. Does this step clash with, combine with, or punish any natal branch — above all the branches at the chart’s key positions?
- Overlay the year. Within one ten-year step, ten liu nian can each read differently; the step sets the climate, the year sets the weather.
And the standing caveat: luck pillars read out tendencies and rhythm, not events. The classical case histories — “this da yun, that year, such an outcome” — were largely written after the fact and chosen for the telling. They work as worked examples, not as laws of prediction.
The Western reader’s comparison: transits and progressions#
Western astrology has a strikingly close pair of techniques. Transits — where the planets actually are now, read against the natal chart — are the direct counterpart of liu nian: real time returning to a fixed chart. Closer still is secondary progressions, which take the days after birth as the years of life: day one after birth is year one, day two is year two. That “one day per year” is the same move Bazi makes with “three days per year” — a short astronomical period stretched by a fixed ratio into a life-long one, then read as if it were the long period. The two traditions share no astronomy and no texts, and arrived at the same device independently — a coincidence rare enough to be worth noticing.
The difference is granularity. Progressions advance continuously, a day at a time; da yun moves in ten-year steps. That is why Bazi cares about the changeover (jiao yun 交运) — the stretch where one step ends and the next begins, where the ladder’s largest drop falls.
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