Why was the Hue Imperial City built on the land of eight old villages?
The Hue Imperial City did not rise on empty ground. The chosen area was originally a zone of mounds, ponds, and lagoons within the territory of eight prosperous villages on the north bank of the Perfume River, and when it was selected as the capital the villagers had to move away. The Dai Nam thuc luc records that in the second year of Gia Long (1803), the king sent the supervisor of works Nguyen Van Yen to survey and mark out the four outer sides of the old Phu Xuan citadel for expansion, and the king personally determined how the citadel would be built. The expansion affected the people's homes and fields, so the court carried out a policy of compensation for houses and gardens.
In the fourth month of the year At Suu (1805), after the Ministry of Rites chose an auspicious day for the ceremony honoring heaven and earth, King Gia Long ordered the ramming of the citadel to begin. More than thirty thousand soldiers and laborers, mainly from Quang Binh to Quy Nhon, were mobilized. At first the citadel was rammed with earth and faced outside with wooden planks, and from the fourth to the eighth month it was completed. Brick construction only began in 1818. King Gia Long died in 1820 with the work unfinished; King Minh Mang succeeded him and continued, repairing the flag tower in 1831 and building the inner facing on the right and rear sides. By 1832 the construction of the Imperial City was finished. The whole undertaking thus lasted nearly 30 years, with years of work, years of rest, and years of repair after flood damage.
What roles do the Perfume River, Ngu Binh Mountain, Hen Islet, and Da Vien Islet play in the terrain?
According to the feng shui landscape axis diagram of Dr. Phan Thanh Hai cited by Bao Thanh Nien, the Hue Imperial City and its system of walls all lie on an axis facing south to southeast, built on the topography of Ngu Mountain and the Perfume River. The main axis of the system runs through the middle of the peak of Ngu Binh Mountain, called the dung dao (central axis), straight northwest to southeast, cutting through the center of the Imperial City. On that axis are the Flag Tower, Ngo Mon Gate, Thai Hoa Palace, Can Chanh Palace, and Hoa Binh Gate.
Ngu Binh Mountain, also called Ngu Mountain for short, formerly known as Hon Mo or Bang Mountain, is an earthen hill 103 m high on the south bank of the Perfume River, about 4 km south of the Imperial City. The mountain is trapezoidal with a flat top, and two small peaks flank it, called Ta Phu son and Huu Bat son, named by King Minh Mang in 1822. The Dai Nam nhat thong chi of the Nguyen court's National History Bureau describes the mountain rising from flat land like a screen forming the first front screen before the Imperial City. The Dai Nam du dia chi uoc bien of chief editor Cao Xuan Duc also records the mountain as squarely shaped like a screen, the most important front screen before the Imperial City.
As for the two islets in the river, research articles in Bao Thanh Nien call Hen Islet and Da Vien Islet the two elements corresponding to Thanh Long (Azure Dragon) and Bach Ho (White Tiger) according to the source's naming. This is a reading of terrain through loan dau (dragon-head feng shui): on the left and right of the site, mounds or alluvial islets embrace and shield it. The Nhap mon loan dau, discussing the minh duong, also stresses that the auspiciousness of the minh duong lies in convergence, the embrace of Long and Ho, a horizontal front screen, and waters flowing toward the site. Phong thuy co dai Trung Quoc: ly luan va thuc tien, volume 2, calls the mound to the left of a structure the Thanh Long sa and to the right the Bach Ho sa, serving to protect and strengthen the foundation's power. Compared with the Hue terrain, the Perfume River flowing across the front of the citadel acts as the minh duong, Ngu Binh Mountain as the front screen, and the two islets on either side as left and right flanks.
Table comparing the terrain elements
| Element | Position relative to the citadel | Role in loan dau | Practical role |
|---|---|---|---|
| Perfume River | Flows across the front of the citadel | Minh duong, gathering water, receiving vitality | Water transport, water source, natural moat |
| Ngu Binh Mountain | South bank of the Perfume River, about 4 km south | Front screen, shielding screen before the citadel | Landscape axis landmark, viewpoint from the Flag Tower |
| Hen Islet | One side of the river, left flank of the terrain | Corresponds to Thanh Long per the source | Alluvial accretion, anchorage, settlement |
| Da Vien Islet | One side of the river, right flank of the terrain | Corresponds to Bach Ho per the source | Alluvial accretion, anchorage, settlement |
| Citadel moat | Surrounds the four sides of the citadel | Water belt embracing the site | Defense and drainage |
| Old mounds, ponds, lagoons | Base of the eight villages on the north bank | Old ground reworked into the capital platform | Filling, resettlement, earth for building |
The table shows that each terrain element has two layers of meaning. The first is how the ancients read the terrain in loan dau terms. The second is practical function: transport, defense, drainage. The two layers do not exclude each other but usually overlap, since a river is both a minh duong and a waterway, a mountain both a front screen and a landmark.
Why does the citadel face southeast rather than due south?
The Hue Imperial City faces southeast, unlike the Forbidden City in Beijing which faces due south. This is a point that sources note as a distinctive feature of the Nguyen capital. The English Wikipedia article on the Imperial City of Hue states that the citadel is oriented toward the Perfume River to the southeast, and that unlike Beijing, the residential area is not arranged in concentric rings around the king's palace but is offset to the southeast of the citadel, closer to the river.
As for the reason, sources offer explanations that do not fully coincide. The first explanation is the river: the citadel face looks out on a bend of the Perfume River flowing across, taking the water as its minh duong, so the citadel's direction is tied to the river's flow and bend. The second explanation is the front-screen mountain: the main axis of the wall system runs through the middle of Ngu Binh Mountain's peak, meaning the citadel's direction was chosen so that this axis points straight at the front screen. These two explanations lead to the same result on the ground but emphasize different elements, one water and one mountain. Bao Thanh Nien, describing the wall system, also uses a combined phrasing: the citadel faces south to southeast, built on the topography of Ngu Mountain and the Perfume River. This combined phrasing shows that the source itself does not fully separate the two elements.
It should be said clearly that this is where sources disagree on the weight of each reason, not where facts conflict. The southeast orientation itself is recorded by all sources. Which factor is more decisive, the river or the mountain, each document leans a different way. This article follows the presentation of Bao Thanh Nien and English Wikipedia, that is, it states both explanations and does not choose one side.
Vauban-style fortification combined with Eastern layout
The Hue Imperial City was built in the Vauban style, nearly square, with an area of 520 ha and a perimeter of over 10,500 m. The wall system includes the Imperial City (outer citadel), the Hoang Thanh (Imperial Enclosure), and the Tu Cam Thanh (Forbidden Purple City), all on one axis. According to the Dai Nam thuc luc cited by Bao Thanh Nien, the four sides of the citadel measure 2,487 truong 4 thuoc 7 tac, the four moat sides 2,503 truong 4 thuoc 7 tac, with 10 gates. In 1818, 24 forts were built on the walls: at the front the Nam Minh, Nam Hung, Nam Thang, Nam Chinh, Nam Xuong, and Nam Hanh forts; on the left the Dong Thai, Dong Truong, Dong Hoa, Dong Phu, Dong Vinh, and Dong Binh forts; at the rear the Bac Cung, Bac Hoa, Bac Thanh, Bac Trung, Bac Thuan, and Bac Dien forts; on the right the Tay Thanh, Tay Tuy, Tay Tinh, Tay Duc, Tay An, and Tay Trinh forts. At the northeast corner the Thai Binh fort was raised, and the flag tower is 4 truong 4 thuoc high.
Notably, the Vauban style is originally a Western fortification technique, with bastions, angles, and deep moats to resist artillery. But placed in Hue, it was reorganized according to an Eastern layout: the dung dao axis running through the center, the front screen a mountain, the minh duong a river, the flanks islets. In other words, Western-style construction technique was placed within an Eastern cultural-geographic scheme. This is what makes the Hue Imperial City different from a purely Vauban fortress.
Shortcomings noted by sources
Alongside the elements considered favorable, some sources also note the disadvantages of choosing Phu Xuan as the capital. English Wikipedia on the Imperial City of Hue lists three points: first, the narrow terrain and isolated location made it hard to mobilize large resources when trouble arose elsewhere; second, it was far from both economic and military centers, the Red River Delta and the Mekong Delta, so transporting rice, food, soldiers, and minted money among Gia Dinh, Hue, and Hanoi was a burden; third, its location near the sea made it hard to defend if Thuan An inlet were blockaded. This source also cites British ambassador John Crawfurd, who visited Vietnam in 1822, saying that choosing Hue as the capital was a bad idea. It should be noted this is one source's record, set beside other assessments that consider Hue's terrain a royal site. Raising it here is not to conclude auspiciousness or inauspiciousness but to show that even among researchers, evaluations of Hue's terrain differ.
Why must feng shui be read alongside practical reasons?
The elements called feng shui in the Hue Imperial City terrain can all be read in parallel with practical functions. The Perfume River is the minh duong and also the main water transport axis. The citadel moat is a water belt embracing the site and also a defense and drainage system. Ngu Binh Mountain is the front screen and also the landmark for the landscape axis and the viewpoint from the Flag Tower. Hen Islet and Da Vien Islet are the flanks and also places of alluvial accretion, anchorage, and settlement. Reading these two layers of meaning helps avoid both extremes: neither treating feng shui as baseless superstition nor treating it as the sole explanation for every planning decision. With the Hue Imperial City, one can say the ancients both read the terrain in loan dau terms and solved the problems of transport, defense, and drainage, and the two things were usually done at the same time.
Traces today and restoration work
The Complex of Hue Monuments was inscribed by UNESCO as a World Cultural Heritage site in 1993, of which the Hue Imperial Enclosure is a part with an area of 159.71 ha and a buffer zone of 71.93 ha. After the Nguyen dynasty ended in 1945, the site suffered much damage from war and weather, and is now being restored.
As for residents in the heritage area, from 2019 to 2023 Thua Thien-Hue province relocated more than 5,000 households living in zone I of the Imperial City system under Phase 1 of the Project for the Preservation, Restoration, and Enhancement of the Hue Imperial City System. Phase 1 completed the construction of 10 resettlement areas with a total area of nearly 83 ha. Phase 2 (2023-2025) continues relocating households in the Complex of Hue Monuments outside the Imperial City. The Mang Ca area after site clearance is about 42 ha, and the Thuong Thanh, Eo Bau, and Phong Lo route areas over 20 ha. As for Ngu Binh Mountain, encroachment for cemeteries from the foot up to nearly half the mountain on all four sides has been recorded, and the province has assigned Hue city to carry out a project to clear, relocate graves, and improve the area, with Phase 1 prioritizing the foot of the mountain from Ngu Binh street inward, about 9 ha.
