THEORIES & PRINCIPLES OF THE IMPERIAL COURTS
 
In his efforts to assure the unity of the country under the imperial house, Emperor Gia Long ordered the construction of the imperial courts in the capital Ph Xun (Hu) in 1805. Although the planning of the capital city was conducted earlier with help from his French advisors and engineers such as bishop Chaigneau and Olivier de Puymanuel, the Hue imperial courts were closely and systematically modeled after the Peking courts but at a smaller scale. To fully appreciate the architecture of the Hue imperial courts mandates an understanding of the concepts and principles of behind ancient Chinese architecture.

Geomantic considerations for siting ancient cultures of China and Viet Nam placed great importance of phong thuy (geomancy or feng-shui) in the siting of a house, a tomb or a palace. Earthly and heavenly currents had to combine in a harmonious knot in the heart of the building in order that whoever resided there should reap the good spirits and is capable of keeping away the evil ones. The capital city of Ph Xun (Hu) best exemplified the geomantic requirements of a good site: the city is facing the Hng (Perfume) river with the hills of Ni Ng on the horizon to protect the imperial gates from evil spirits.

Organization of Space
In the ancient Chinese cosmology, which considered Heaven round and Earth square, space is imagined as a series of overlapped squares. The center of this "ranked" space is the capital-a square core marked by four gates at the four cardinal points towards which the cosmic influences coverage. Architectural space is like a series of closed worlds, of complete independent, progressively smaller units which repeat on a reduced scale the forms of the larger units. The imperial city is a series of enclosures cunningly encasing the throne room, which is the very heart of the Empire.

Orientation and Axiallity
The concept of order and harmony in the universe is reflected in the many rules that governed the siting of an edifice. One of the principle rules is the main North-South axis. According to ancient belief, North represented the rigors of winter and the threat of barbarian invasion-namely evil influences. Hence all important buildings of the imperial court opened towards the south. This axiallity implied a median avenue and the procession of the architectural complex as one moves northward along it. The major buildings such as Ng Mn (Noon Gate), Thai Hoa palace, Can Chanh palace follow each other along the median axis, proceed by vast courtyards and entoured on the East and West by buildings of secondary importance.

The Theories of Âm Dng (Yin and Yang) and the Ng Hnh (Five Elements) in Ancient Architectural Design
The theories of Yin and Yang and the Five Elements exerted strong influences on accent Chinese architecture. According to Chinese classics, "Yin and Yang" is the "cardinal principle of all things, of the way of heaven and earth", meaning that everything can be divided into the mutually opposing and independent elements. Yin stands for shady slopes of mountains, for cold rainy weather, for the right hand, for all that is feminine and passive. Yang stands for the sunny side, for heat and drought, for the left hand, for all that is masculine and active. Universal harmony is the sum of these opposite and complementary energies. Man is conditioned by this rhythm of a nature that is in a constant state of flux. The human space therefore was made to harmonize as far as possible with the rhythm of nature. The design of the imperial city closely reflected this concept of harmony: in each court delightful gardens are replicas in microcosm, with rocks and miniature trees and tiny lakes, of the great world with its mountains, forests and limitless oceans.

In additional to the principles of Yin and Yang, ancient Chinese architecture also followed the theories of Five Elements such as "water, fire, wood, metal and earth" or "north, south, east, west and center" or "green, yellow, red, white and black" or "coldness, heat, wind, dryness and dampness". The five elements represent the five different kinds of matter that people constantly come in contact with. For example green is the color of sprouting leaves symbolized the spring and youth, and corresponds to the east. Following this pattern, Thai Mieu palace where the shrines of the founding lords of Nguyen dynasty are housed, is located in the western side of the court while Thê Miêu palace housed the stele of the later Nguyen emperors are located in eastern side.

Minh Bui
References: The Ancient Architecture of China