Bagua

The Bagua is a spatial arrangement rather than a single fixed image: eight trigrams, each a stack of three broken or unbroken lines, placed around a central point, most often around a Taijitu, the black and white yin-yang emblem already recorded separately in this atlas. Richard Smith's history of the Yijing describes two standard arrangements that differ structurally rather than as loose variants of one scheme: the Earlier Heaven, or Fuxi, sequence, associated with a cosmological, before-manifestation ordering of the trigrams, and the Later Heaven, or King Wen, sequence, associated with the world of active change and used as the compass-direction basis for most practical feng shui work, place the same eight trigrams in genuinely different positions around the circle, so a Bagua diagram is only meaningful once the reader knows which of the two sequences it is drawing on.

Smith notes that traditional Chinese cosmological texts treat the Earlier Heaven sequence as describing an ideal, pre-manifest cosmic order and the Later Heaven sequence as describing the world of observable change and practical action, a conceptual division that explains why the two arrangements are not treated as competing corrections of one another but as descriptions of two different cosmological registers.

Smith traces the Bagua's use outward from its role inside the Yijing's own divinatory and philosophical system into Daoist cosmological diagrams, into feng shui compass instruments such as the luopan, and into folk protective practice, where a Bagua mirror, a small octagonal mirror painted with the eight trigrams, is hung outside a doorway or window understood to face a source of inauspicious influence.

In compass-based feng shui specifically, the Later Heaven sequence maps each of the eight trigrams onto a compass direction and, through that direction, onto an associated family member, natural force and Wu Xing phase, a mapping this atlas records in the Direction entity type rather than repeating here, since the trigram-to-direction correspondences are the same underlying structure viewed from the compass side rather than a second, competing scheme. The Bagua mirror's protective use, hanging a small mirror bearing the eight trigrams to face and deflect an inauspicious external structure or feature, remains common in Chinese and Chinese diaspora domestic and commercial practice today, one of the more visibly persistent folk applications of classical Yijing cosmology in ordinary contemporary use rather than only in specialist feng shui practice.