Dayun: Reading a Zi Wei Chart in Ten-Year Chapters
Dayun does not tell you whether a decade will be good or bad. It slices a life into ten-year chapters and marks which palace's themes move to the foreground in each one.
The short version
Dayun is the ten-year segmentation used in Zi Wei Dou Shu: each chapter covers ten years of life, and the chapters advance through the chart one palace at a time by fixed rules. Its job is not to grade a decade. It changes the seat you observe from — the same natal chart, viewed from a different palace every ten years, puts a different set of themes in the foreground.
Three points worth fixing early:
- Dayun is a scenery layer, not a scoring layer. It says which palace the conversation of a decade revolves around, not whether that decade will be smooth or difficult.
- Both the starting age and the direction are mechanical. Starting age comes from the Five Element Bureau; direction comes from the yin or yang of the birth-year stem. There is no room for interpretation in either rule.
- Dayun is always read on top of the natal chart. Which natal palace a dayun Life Palace lands on is the first question to ask.
Which time layer dayun occupies
A Zi Wei chart has three time layers. At the bottom sits the natal chart, fixed at the moment of birth and never revised. In the middle sits dayun, renewed every ten years, supplying long-running scenery. On top sit the annual charts (liunian), renewed every year, carrying the themes of a single year. The layers stack rather than replace one another: the year sits on the decade, and the decade sits on the natal chart.
An analogy: the natal chart is the structure of a building; dayun is the floor you live on for ten years; the annual chart is which room you decide to furnish this year. Move to another floor and the view changes, but the building is still the same building.
Starting age: the Five Element Bureau
Not everyone enters their first dayun at the same age. The starting age is set by the Five Element Bureau (wuxing ju), of which there are exactly five, and the Bureau's number is the starting age counted in nominal years:
| Bureau | Starts at | First chapter |
|---|---|---|
| Water-2 | age 2 | ages 2–11 |
| Wood-3 | age 3 | ages 3–12 |
| Metal-4 | age 4 | ages 4–13 |
| Earth-5 | age 5 | ages 5–14 |
| Fire-6 | age 6 | ages 6–15 |
After the first chapter, every chapter lasts ten years: a Water-2 chart runs 2–11, 12–21, 22–31, and so on. Because the starting ages differ, two people who are both forty may structurally be standing in different chapters — one in her fourth, one in his third.
Where the Bureau comes from
The Bureau is derived from the stem-and-branch pair of the Life Palace through the nayin (a classical system that maps each of the sixty stem-branch pairs to one of the five elements). Whichever element — water, wood, metal, earth, or fire — the Life Palace's pair maps to decides the Bureau, and with it the starting age.
One frequent confusion is worth clearing up: the Bureau is not taken from the birth year's nayin. It is taken from the nayin of the Life Palace's position, and the Life Palace itself is fixed by the birth month and hour. This is why an error in the birth time does not merely shift the Life Palace — it can change the Bureau, the starting age, and the age brackets of every decade that follows. It is one more reason birth-time accuracy matters.
Forward and backward: the order of the decades
The direction in which the chapters advance is decided by the yin or yang of the birth-year stem: yang-year men and yin-year women run forward; yin-year men and yang-year women run backward. Of the ten stems, jia, bing, wu, geng and ren are yang; yi, ding, ji, xin and gui are yin.
Forward means the second chapter begins at the natal Parents Palace; backward means it begins at the natal Siblings Palace. From there the chapters move one palace per decade, in the same direction for life. Listing every dayun a person will ever have therefore needs only three inputs: the starting age, the direction, and the fact that the first chapter sits on the natal Life Palace. Everything else is mechanical derivation.
Why dayun counts in nominal age
Dayun ages are always counted in nominal age (sui): a person is one at birth, and gains a year at each lunar new year. That puts nominal age one to two years ahead of Western age reckoning. So "starts at age 2" on a Water-2 chart means the first ten-year chapter begins shortly after birth, not at the second birthday. When a chart prints an age bracket for your current chapter, remember the label is in sui — to map it onto calendar years, convert through nominal age rather than subtracting your birthday age directly.
Reading dayun: two layers stacked
Once a chapter's Life Palace is placed, the other eleven palaces are renamed relative to it, producing a full "dayun twelve-palace" overlay on top of the natal twelve. Every position now carries two identities at once: its natal identity and its dayun identity. The conventional reading order is three steps:
- Locate. Which natal palace does the dayun Life Palace land on? That palace's natal theme becomes the floor of the decade.
- Read the structure. Which natal palaces does the dayun Life Palace's own triangle (its trinity plus opposite palace) press on? The themes pressed stay in the room for the whole decade.
- Overlay the transformations. The stems of the dayun palaces generate a fresh layer of dayun transformations (dayun sihua) attached to the stars. Birth-year transformations are the factory labels; dayun transformations re-annotate them for the decade; annual transformations make the year-level fine adjustment.
Walk the three steps and you have the outline of what a decade's conversation revolves around — still without a single fortune-telling sentence.
Three common misreadings
Misreading one: treating dayun as a score. "This is a bad decade, the whole ten years are ruined" is not an output of the system. Dayun describes where the thematic weight sits; the same structure unfolds differently in different lives, and the structure itself contains no outcome.
Misreading two: looking only at the dayun Life Palace. The dayun Life Palace must be read together with its own triangle, and then pressed back onto the natal chart. Judging a decade from that one palace's stars alone flattens two layers into one.
Misreading three: merging dayun and the annual layer. A decade is scenery; a year is a theme. Reading dayun with year-level granularity over-magnifies it; reading a single year with decade-level granularity blurs it. Each layer has its own resolution.
First time looking at your dayun
- Which Bureau is my chart? What is my starting age in sui?
- Which chapter am I in now, and which calendar years does it cover?
- Which natal palace does my current dayun Life Palace land on, and which natal identity does it double?
- Which natal palaces does the dayun triangle press on?
- Which stars carry the dayun transformations, and in which direction?
Five questions, and the structural position of your current decade is clear. To cast your own chart, start with the free chart generator; for how transformations attach to stars, read The Four Transformations: four directions of attention; for the Life Palace itself, see The Life Palace: a disposition, not a verdict.
Notes
This article describes the structural rules and reading order of Zi Wei Dou Shu, compiled from standard charting practice, for self-understanding and cultural study. It is not a fortune reading, medical advice, or investment advice. Dayun describes thematic weight, not predicted events.
Common questions
What is dayun?
Why does everyone's dayun start at a different age?
How is the Five Element Bureau determined?
How do I tell forward from backward dayun?
Are dayun ages nominal age or actual age?
Does a good dayun mean ten smooth years?
What is the relationship between dayun and the annual chart?
How do I find my current dayun?
This site draws on classical Chinese texts for cultural and self-reflective use. Nothing here is prediction, medical, legal or financial advice.