Later Heaven Bagua

The order comes from a passage describing the trigrams in sequence as a process: activity begins in one quarter, the things of the world come forth, they are set in order, they labour, they are brought to completion, and the cycle returns to its start. Read as a circle that gives each trigram a direction and a point in the year, and the resulting figure describes the world in operation rather than in balance.

Opposite trigrams are no longer complementary pairs, which is the visible difference from the other arrangement. That directional assignment is what connects the figure to the rest of Chinese correlative cosmology. Each direction already carried a season, a phase, a colour and a class of things, and the trigrams slot into that framework, so a single position on the circle can be read for its trigram, its season, its phase and its associated qualities at once. It also maps onto the nine cell square of numbers known from the same body of tradition, with the eight trigrams arranged around a centre that belongs to none of them. That correspondence is what makes the arrangement usable as a grid laid over a physical space rather than only as a circle to be contemplated, and it is the basis of every practice that divides a site, a building or a room into eight sectors and a middle. Once a figure can be laid on a floor, it can be used to make decisions about that floor, and that is the whole of the difference in how the two arrangements are employed.

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.