Luck Pillars 大运
Dà Yùn · Ten-year periods that add a fifth pillar to the chart in turn.
What it means
Da Yun, usually translated Luck Pillars or Major Luck, is a sequence of ten-year periods derived from the month pillar. The sequence runs forward or backward through the sixty combinations depending on the polarity of the year stem and the sex of the person, and the starting age is calculated from the distance between the birth moment and the nearest solar term.
Why it matters
Luck Pillars are what make BaZi a system about timing rather than a fixed personality description. Each period adds a stem and branch that interact with the natal chart, so the same chart reads differently at thirty and at sixty. The starting age is not arbitrary — three days between birth and the neighbouring solar term conventionally counts as one year of age.
Where this site uses it
The free tools on this site cover the natal chart only. Luck Pillars require a judgement about direction and starting age, so they belong to the paid reports rather than to a table anyone can read off.