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The Kuei, Ch’ang, Hu, and Huang are all flat, like the Pi, but unlike the Ts’ung. Possibly derived from the shape of a primitive knife blade, the Kuei was rather plain in its early versions. A symbol of the East, or Spring, and of Imperial Power, it became customary to carve symbolic figures on its face. The Twelve Branches, The Twelve Ornaments, and any number of other potent figures have been used for such decoration. Unfortunately, the form and origin of the South, or Summer, worshiping jade is somewhat of a mystery because no authentically identified Ch’ang is known.
There has been a decided change in the Hu from its beginning form. It started as a flat, primitively formed tiger which is hardly recognizable as we think of tigers now. Strangely, it is one of the very few animal symbols dating to before the Han Dynasty. Primarily an object of worship for the West, or Autumn, the Hu has also been used as a symbol of military power or authority. This concept adds deeper meaning to the epithet “paper tiger.”
Basically, the Huang is half a Pi and was for worship of the North, or Winter. For embellishment it gradually became customary to carve the curved, flat object as a dragon, or fish.