The Arrangement Practice Actually Uses

Feng shui works almost entirely from this figure. In the compass based schools it is one of the rings on the instrument used to take a site's orientation, read against the building's facing direction and the occupants' own numbers to produce judgments about particular sectors. The method is technical, cumulative and dependent on accurate measurement, and it takes considerable training.

A simplified version travelled to the West in the later twentieth century, in which the eight sectors are laid over a floor plan aligned to the entrance rather than to the compass, and each sector is given a life area such as wealth, relationships or reputation. That is a modern adaptation with a different theory behind it, and practitioners of the compass methods generally regard it as a separate practice rather than a version of theirs. The atlas records both without adjudicating between them, since the disagreement is internal to a living tradition and is about correct practice rather than about a fact the atlas could settle. Describing a living practice is not the same as ruling on it. What can be stated plainly is the historical relationship between the layers, and it is a clear one: the seasonal statement about the trigrams is ancient and is in the classical commentary, the circular diagram everyone now pictures is a Song dynasty development, and the floor plan overlay aligned to a doorway is a product of the last several decades.