What is Da Yun in BaZi?

It is the ten-year luck cycle layer of a chart. Each cycle is a stem-branch pair that follows the month pillar, read alongside the fixed natal chart and the annual pillars.

How is the start age calculated?

By counting from the birth time to the nearest solar term in the direction of travel: three days equal one year, one day equals four months, one hour roughly ten days.

Can luck cycles change my chart?

No. The four pillars stay the same; cycles add conditions around them. A reading describes how the fixed chart meets changing emphasis, not a new chart.

Luck cycles (Da Yun) in BaZi

How BaZi luck cycles are calculated: the direction taken from the year stem and gender, the start age measured from the nearest solar term, and how each decade is read with the ten gods.

A BaZi chart is fixed at birth: four pillars that never change. The luck cycles are the moving layer above it. Each cycle lasts ten years and is written as one stem and one branch, starting from the month pillar and moving through the sexagenary cycle.

This page explains how a cycle is calculated and how it is read. It does not predict events: a cycle describes conditions and emphasis, not a schedule.

What a luck cycle is

The month pillar of your chart is the seed of the luck sequence. From it, the cycle moves one step at a time either forward or backward through the sixty stem-branch pairs. A full decade is written as one pillar; many readers take the stem as the first five years and the branch as the second five, while others read the pair together. Both conventions exist — what matters is consistency.

Which direction the cycles run

Direction depends on the polarity of the year stem and on gender. Yang year with a male chart, or yin year with a female chart, runs forward. The other two combinations run backward.

Year stem	Chart	Direction
Yang (Jia, Bing, Wu, Geng, Ren)	Male	Forward
Yin (Yi, Ding, Ji, Xin, Gui)	Male	Backward
Yang (Jia, Bing, Wu, Geng, Ren)	Female	Backward
Yin (Yi, Ding, Ji, Xin, Gui)	Female	Forward

When the first cycle begins

The start age is measured from the distance between the birth moment and the nearest solar term in the direction of travel: three days count as one year, one day as four months, and one hour as about ten days. The calculator applies the traditional rule with the actual term times for the birth year.

Because the start age depends on the exact birth time and the year’s solar terms, two people born on the same day can begin their cycles months apart.

Reading a decade

The stem of the cycle names the theme: its ten-god relationship to your Day Master is what the decade emphasises.
The branch describes the environment: the element and hidden stems that surround the theme.
Annual pillars are the weather inside the decade; they change every year and are read against both the chart and the cycle.
No cycle is simply good or bad. The same cycle can be demanding in one chart and supportive in another.

A worked example

Take a Jia Wood Day Master. A Bing Yin cycle is Yang Fire over Yang Wood: Bing is the element Jia produces, so the decade emphasises output — visibility, craft and voice. The Yin branch is also Wood, the Day Master’s own element, so the environment supplies support while the stem asks for expression. Read together, the decade is about turning capacity into something visible.

What luck cycles are not

A cycle is not a timetable of events, and it does not override the chart. It describes where attention is likely to be drawn and what kind of effort the period rewards. Treat it as a lens for reflection, not a forecast you owe obedience to.

Frequently asked questions

What is Da Yun in BaZi?: It is the ten-year luck cycle layer of a chart. Each cycle is a stem-branch pair that follows the month pillar, read alongside the fixed natal chart and the annual pillars.
How long is each luck cycle?: Ten years. Many readers take the stem as the first five years and the branch as the second five; others read the pair as one decade.
How is the start age calculated?: By counting from the birth time to the nearest solar term in the direction of travel: three days equal one year, one day equals four months, one hour roughly ten days.
Can luck cycles change my chart?: No. The four pillars stay the same; cycles add conditions around them. A reading describes how the fixed chart meets changing emphasis, not a new chart.

See it in your own chart

Enter your birth date, time and place, and the calculator returns the four pillars, your Day Master, the five-element balance and the luck cycles.

Cast your free BaZi chart

This page is a study aid for classical BaZi symbolism, not a prediction. It describes tendencies and temperaments, not events, outcomes or dates. For medical, legal or financial decisions, consult a qualified professional.

Last updated 2026-11-09