Method
The chart is cast on local time, not on the clock you were given
Zi Wei Dou Shu (紫微斗數) is a Chinese system that places a chart of twelve palaces by the lunar calendar and the double hour of birth. It has been in continuous use for roughly a thousand years, and it is still read the same way today.
One
Where you were born changes your hour
A hospital clock reads zone time. A chart needs the sky over that place at that moment, so every chart here is corrected twice: once for the longitude of the birthplace, and once for the equation of time, the seasonal drift of up to sixteen minutes between clock noon and solar noon. In a place like Los Angeles the correction moves the reading by around nine degrees of time. At the edge of a double hour, that is the difference between two palaces.
This is why the birthplace is required and why an approximate one is offered rather than a guessed one. If the hour falls within a few minutes of a boundary, the reading says so and tells you which two readings are possible.
Two
The twelve palaces
The chart is a square of twelve houses. Each house is a department of a life: the self, siblings, spouse, children, wealth, health, travel, friends, career, property, the inner life, and parents. The ruler star that lands in a house colours everything that house describes. The first thing anyone reads is the Life palace; the second is what sits directly opposite it.
Three
Brightness, and the four transformations
Each star carries a brightness in the house it occupies, from peak to fallen. Brightness does not mean good: a bright star is simply more itself, and a difficult star at peak is more difficult. Over the chart sit the four transformations, Prosperity, Power, Fame and Obstacle, which mark the four places where the chart's pressure and opportunity actually land. The palace holding Obstacle is usually the first honest conversation of a reading.
Four
Decades, not dates
The chart is divided into ten-year periods, each ruled by one of the palaces and beginning at the age the chart itself specifies. A decade tells you what a stretch of life is about. It does not tell you what happens on a Tuesday, and no honest practitioner of this system will claim otherwise.
Five
What this is not
It is not a prediction service, and it is not a substitute for a doctor, a lawyer or an accountant. It has no opinion on whether you will marry, on how much you will earn, or on how long anyone will live. What it does well is describe the shape of a temperament and the places where it tends to get caught, which is usually enough to be useful.
Every piece of written language on this site is either generated from the chart and then reviewed by a person, or written by that person outright. The chart itself is computed, and the computation is public: the same library, the same corrections, for everyone.