BaZi · Four Pillars
Luck pillars: the ten-year blocks of a BaZi chart
A BaZi chart keeps time twice. The four pillars are fixed at birth; the luck pillars — ten-year spans, each headed by one stem and one branch — are laid over them in order.
Luck pillars (大运, dà yùn) divide a life into ten-year blocks from a computed starting age, each block one pillar of a stem and a branch. Rimo computes them from the birth moment to the nearest 节 and prints the whole sequence with the chart.
What a luck pillar is
The four pillars are the chart; the luck pillars are the clock laid over it. Ten spans run in one direction from the month pillar — forward or backward according to the polarity of the birth year and the gender — and each span is read as a change of weather rather than as an event: which element is in charge, and what it does to the Day Master.
How the starting age is computed
The start is measured from the birth moment to the nearest 节 (立春, 惊蛰, 清明 …) and counted at three days to a year, one day to four months. Because the interval is measured in solar terms rather than calendar days, two children born a week apart can begin their luck pillars years apart.
What the sequence in the chart shows
Each row gives the pillar, the age it begins at and the year it begins in. The lines are printed in order, so a reading can name the span you are in and the two either side of it.
Cast a chart and read the luck pillars
Luck pillar and annual pillar
A luck pillar is the decade; the annual pillar (流年) is the single year inside it. The decade sets the field, the year sets the weather in it — and a good year inside a hard decade is still a good year.
How they are read
Against the Day Master and against the four pillars. A span is not good or bad in itself: it brings one element forward, and that element either supports the Day Master or works against it. The ten-year spans of Zi Wei Dou Shu are a separate clock in the other system.
Questions
How many luck pillars are there?
The chart prints ten, covering a century. The ones that matter in a reading are the span you are in and the two either side of it.
Do men and women run in opposite directions?
The direction follows the classical convention — forward or backward from the month pillar, set by the polarity of the birth year and the gender — and the chart prints the direction it used.
Is a luck pillar a prediction?
It is a period marker. A reading says what a span brings forward and where the chart is pressed by it; it does not name events.
Cast a chart and read the luck pillars Day Master Calculator — the stem of your day pillar Da xian and liu nian — the other system's clock FAQ