Bagua (八卦)

The eight trigrams — the eight-fold grid the tradition uses to divide a space or a direction. The bagua are eight three-line figures, each standing for a natural image (heaven, lake, fire, thunder, wind, water, mountain, earth). In feng shui they serve as the eight-fold division applied to a floor plan, a site, or the compass.

It belongs to the classical vocabulary of the tradition. The eight trigrams — the eight-fold grid the tradition uses to divide a space or a direction. Confusing the two arrangements is the most common technical error in the sources' own warnings — the tradition states repeatedly that the Earlier Heaven order describes principle while the Later Heaven order is the one applied.

Two arrangements are used: 先天 (Earlier Heaven), which the sources treat as the ideal order, and 后天 (Later Heaven), which is the arrangement actually applied to directions and to the Eight Mansions method. The classical texts are careful about which one is in use. It is grouped under Earth (土) in the five-element system.