Major Luck Period大運

While the natal BaZi chart is fixed, Daeun changes every 10 years, representing shifting environmental and temporal energies. Calculated from the Month Pillar moving forward or backward in the cycle, each Daeun consists of a Heavenly Stem and Earthly Branch.

The starting age (Daeunsu) is calculated from the number of days between birth and the nearest solar term. Men born in Yang years follow the forward cycle; women follow the reverse (and vice versa). A Daeunsu of 5 means the first Daeun begins at age 5, then shifts at 15, 25, 35, etc.

A favorable Daeun (favorable cycle) helps the natal chart's potential bloom. A challenging Daeun exposes the chart's vulnerabilities. Even an excellent natal chart can face difficulties in adverse Daeun — and vice versa.

Analyze how the Daeun's Stem and Branch interact with the natal chart's Day Master, Month Pillar, and other elements (generating, controlling, combining, clashing). Daeun that strengthens the useful element (Yongshin) = favorable; Daeun that weakens it = challenging.