When feng shui speaks of an auspicious site, the four guardians are never left out. The four guardians refer to the mountain forms in four directions that enclose the energy spot where qi settles: the azure dragon of the east, the white tiger of the west, the vermilion bird of the south, and the black tortoise of the north. Bearing the names of the symbolic animals that guard the four directions, it is a concept that shows at a glance the arrangement of mountains embracing and protecting a site from all sides.
Each direction has long been paired with a symbolic animal handed down from old. The dragon of the east is an azure dragon, the tiger of the west a white tiger, the bird of the south a vermilion bird, and the tortoise of the north was depicted as a tortoise and serpent intertwined. These four animals were originally regarded as guardian spirits that divided the constellations of the sky into four directions and watched over them, and in feng shui that symbolism is said to have descended to the earth and come to be applied to the mountain forms surrounding a site. So in the names of the four guardians, direction, color, and the energy of the animal guarding that direction are held together.
The standard for reading the four guardians is the direction seen from the main mountain that supports the back of the site. That is, when one stands at the site with the main mountain at the back and faces forward, the ridge stretching to the left is called the dragon and the ridge stretching to the right the tiger, while the low hill facing it far ahead is the vermilion bird, and the mountain supporting the site from behind is the tortoise. Therefore one must bear in mind that the left and right of the dragon and tiger are not absolute east and west, but mean the left and right as seen when standing at the site with the main mountain at the back.
A good site was held to be a place where the mountains of these four directions embrace it fittingly, so that the energy does not scatter but is well held. The arrangement in which the dragon and tiger cradle the site from left and right as if wrapping it with arms, the tortoise firmly supports the rear, and the vermilion bird faces an open expanse ahead was seen as foremost. In particular, the more the ridges of the dragon and tiger embrace the site not in a single layer but in several layers, the more it was traditionally seen as an auspicious site that shelters it well from wind and keeps the energy lingering deeply.
Such an arrangement of the four guardians can also be observed in the siting of old capitals. Hanyang, fixed as the capital of Joseon, lay in a basin surrounded by mountains and was held to be a place with a form backed by a firm mountain to the north and enclosed by mountains to the left, right, and front. Those who fixed the capital are said to have surveyed the site by reckoning the mountain supporting the rear as the tortoise, the ridges stretching east and west as the dragon and tiger, and the mountain ahead as the vermilion bird. Seen this way, the four guardians did not remain a mere symbol but were a frame of long-standing insight for reading how a site surrounded by mountains and water has sheltered people.
Not every site, however, possesses the four guardians in full, and it was far from rare for the mountain form of one direction to be weak or left open. In such cases people of old sought to fill the lacking part by human means and to bolster the site, and this notion was called remedying. If the tiger side was empty, for instance, they might tend a grove there or raise an embankment, and where a watercourse drained straight off they would plant trees to soften the scattering of energy. This shows that the four guardians did not stop at reading an inborn form alone but touched on a traditional way of thinking that sought harmony by cradling a deficient nature with the human hand. Moreover, the reason the four guardians enclose a site is, in the end, to protect the node where energy was thought to settle at its very center, so that the four guardians, the auspicious site, and the node were held to be a single fabric hard to think apart.
Today the four guardians are read anew not only as signs for divining fortune but as a traditional perception of space holding the wisdom by which people of old examined mountain forms to choose a serene dwelling place. Within that insight, where mountains enclose all four sides to govern the wind and weigh sunlight and watercourses, it is fair to see an old longing to dwell nestled in the embrace of nature.