What is Purple Star Astrology?

Purple Star Astrology — Zi Wei Dou Shu — was born in 10th-century China, credited to the Taoist sage Chen Tuan and refined over the Song dynasty from the I Ching, classical astronomy, and the five elements. It takes its name from the North Star, Zi Wei: the still point the ancients called the seat of the Heavenly Emperor, the fixed center everything else turns around.

BaZi — the Four Pillars (八字) — reads your destiny from four elemental pillars drawn from the year, month, day, and hour of birth. It is elegant and fast, and it tells you the broad weather of a life: that you are, say, a Metal person, strong or weak, born into a favourable season or a hard one.

Zi Wei Dou Shu works at a finer grain. Instead of four pillars it places 108 stars across the twelve palaces — far more data points, and so a far more specific picture.

The difference shows in what each can actually say. One names your element; the other names the room, the star, and what it does there. Much more specific, and much more actionable.