[Korea Route] Why Did Joseon Sukjong Build a 'Seong (Castle)' on Bukhansan?

The Largest National Project of the Sukjong Era... About 13km Perimeter of Mountain Fortress
37 Years of Construction Debates... 'City Contraction' vs 'Mountain Fortress Construction'
Fortress Area Embracing the Mountain Fortress... The Capital's Guardian Mountain, Bukhansan

Bukhanseongdo Sebu Gwansunso [Goyang-si]

[Asia Economy Reporter Ra Young-cheol] Bukhansan has been a mountain that embraced a capital city with the characteristics of a military stronghold and a defense base for the capital since the Three Kingdoms period.

It established itself as the true guardian mountain (Jinsan, 鎭山) of the capital, defending the fortress and protecting the royal family and the citizens within the city.

Why did King Sukjong (1661?1720, reign: 1674?1720), the 19th monarch of Joseon, decide to build a mountain fortress on Bukhansan after decades of debate?

In summary, during King Sukjong’s reign, the Hanyang fortress was constantly exposed to danger due to the invasion of large pirate groups appearing in the Qing Dynasty’s maritime areas.

Moreover, although the war ended in 1637 when King Injo (reign: 1623?1649), who was resisting at Namhansanseong, knelt before the Qing Emperor Taizong, it is understandable that Crown Prince Bongrim (later King Hyojong) did not want to repeat the humiliating history of being taken hostage by the Qing Dynasty.

Just as the ongoing North Korean nuclear threat continues, the domestic and international situation surrounding the Korean Peninsula remains unpredictable even at this moment.

According to records, the construction of Bukhansanseong was not merely a reflection on 'past history' but was intended to protect the royal family, the court, and the residents of the capital from foreign powers amid concerns that another war might break out in Joseon.

King Sukjong firmly believed that building Bukhansanseong was one of the countermeasures to defend the capital from foreign invasions.

He judged that while Ganghwado and Namhansanseong were places where one could not stay long in emergencies, Bukhansanseong was easily accessible, and its rugged terrain made enemy approach difficult, making it a naturally defensible fortress.

In fact, the plan to build Bukhansanseong was also proposed during the reign of King Seonjo (reign: 1567?1608) during the Imjin War. After Seonjo and the court officials who had fled to Uiju returned to Hanyang, they considered building a fortress on Bukhansan as a defense measure in times of war.

However, despite discussions on the pros and cons of construction, the fortress construction could not progress further due to ongoing repairs of fortress walls at several key defense points, as well as shortages of finances and manpower during Seonjo’s reign.

Later, during King Hyojong’s reign (reign: 1649?1659), the construction of Bukhansanseong was again proposed as a national defense strengthening measure. Hyojong, who had experienced humiliating hostage life, pursued a northern expedition policy, but the plan to build Bukhansanseong sank again due to financial difficulties and opposition from the ruling class.

The construction of Bukhansanseong resurfaced during King Sukjong’s accession in 1674, after King Hyeonjong’s reign (reign: 1659?1674). This was due to concerns about the impact of the political situation on the Chinese mainland on Joseon and fears that another war might break out.

Thus, the proposal to build Bukhansanseong was raised.

Bukhansanseong Fortress Walls and Facilities [Goyang City]

■ The 'Construction Debate' of Bukhansanseong

King Sukjong and the court ministers exchanged opinions daily and publicized the debate over the construction of Bukhansanseong.

The debate began when information was received that pirate groups had appeared in the Qing Dynasty’s maritime areas heading toward Joseon.

Efforts were concentrated on strengthening coastal defense around Ganghwado and Incheon, securing firearms, gunpowder, and carts for fortress battles.

Defense strategies by region and efficient military operation plans were proposed, one of which was the construction of Bukhansanseong.

Within the court, opinions were sharply divided between those advocating for the immediate construction of Bukhansanseong and those insisting that efforts should focus on defending the capital.

Panbusa (Chief Administrator) Lee Yu (李濡) submitted a memorial. "If a fortress is built on Bukhansan, an inner fortress (Naeseong) can be established to relocate Jongmyo Shrine and Sajik Shrine in emergencies. Also, by blocking the entrance to the nearby Jojiseo (the government office in charge of paper manufacturing during the Joseon Dynasty), the grain warehouses along the Han River can be relocated and installed. This way, all public and private stockpiles can be moved inside." 『Annals of King Sukjong』, 36th year of Sukjong (1710), October 26

Yun Ji-wan, Yeongjungchubu-sa (Chief of the Central Secretariat), presented his opinion. "Those discussing say that building a fortress on Bukhansan is the foundation for preserving and protecting the capital. However, to protect the capital, a fortress should not be built on Bukhansan. If a fortress is built on Bukhansan, the capital cannot be protected." 『Annals of King Sukjong』, 36th year of Sukjong (1710), November 10

Another compromise proposal emerged: some argued that there was no need to rush the construction and defense of the capital area, prioritizing military training and defense of key strategic points, while others suggested building Bukhansanseong alongside capital maintenance. However, a decision was not easy.

Jinsa (a government rank) Heo Geuk submitted a memorial requesting the contraction of the capital. In response, King Sukjong said, "The capital is vast and large but has the flaw of not being sturdy. If we try to defend it there, it could be precarious. Therefore, I am now thinking day and night. If a special place is decided upon after discussions with many ministers, I will enter with the people to defend it." 『Annals of King Sukjong』, 36th year of Sukjong (1710), October 20

As time passed, the possibility of pirate invasion decreased, but Sukjong thought that if a fortress was built under the pretext of supplementing defense facilities to prevent pirate invasions, it could avoid Qing interference. It is clear that his inclination was toward building the fortress.

In 1637, after Joseon lost the war (Byeongjahoran) to the Qing Dynasty and signed a peace treaty, a clause was included forbidding the contraction and construction of fortress walls.

Opponents of building Bukhansanseong argued that most capital residents wanted to defend the capital and that 100,000 able-bodied men could divide the area and defend the fortress walls.

They claimed it was more advantageous to base military grain and weapon supplies on the capital, and abandoning the capital would mean having to relocate Jongmyo and Sajik shrines again, enduring humiliation once more.

Bukhansanseong Gwanseongsoji and Sangchangji Layout Map [Goyang City]

Less than a month after King Sukjong decided to build Bukhansanseong, concerns were raised about the mountain’s disadvantage of water shortage.

Criticism also arose that the construction of the fortress walls on Bukhansan would damage the geomantic energy (Jimyeok, 地脈) of the capital Hanyang, violate the treaty with the Qing Dynasty, worsen diplomatic relations, and neglect Namhansanseong and Ganghwaseong, exposing vulnerabilities in the defense of the metropolitan area.

Additionally, opinions were voiced that large-scale construction requiring massive manpower was unreasonable during a time of widespread hunger and rampant banditry.

On the other hand, supporters of building Bukhansanseong argued that the capital was too large to defend in times of national crisis, and building Bukhansanseong would make it easier for the capital’s residents to enter and defend together. They also judged that the existing Namhansanseong was difficult to access because it required crossing a river.

They proposed that with 10,000 seoks of rice, 1,000 rolls of cotton cloth, and about 10,000 labor soldiers, construction could be completed within 2 to 3 months.

They also suggested rotating central troops and mobilizing the poor as construction labor. They emphasized the need for a new stronghold since Namhansanseong and Ganghwaseong had been captured during the Byeongjahoran.

This construction debate was weighted more as a defense measure in case of national war rather than just defense against pirate invasions.

Vice Eunggyo (Deputy Minister) Lee Se-choe reported to King Sukjong, "If a fortress is built on Bukhansan and it is truly good for defending the capital, but after building Bukhansanseong the capital cannot be defended, then this is not an appropriate strategy."

To this, King Sukjong replied, "The current discussion to build Bukhansanseong arose after receiving documents warning of pirates in the Qing maritime areas, so this construction plan is seen as a strategy to block these pirates. However, my intention is to build a fortress utilizing the natural terrain to devise a long-lasting strategy." 『Annals of King Sukjong』, 36th year of Sukjong (1710), December 1

King Sukjong focused on the fact that during the Imjin War, the court had to flee to Uiju. He intended to build Bukhansanseong, stockpile military supplies and provisions, and create a stronghold where the capital’s residents could enter and resist in times of war.

He also judged that Bukhansan’s rugged terrain would reduce the effort needed for construction by utilizing natural landforms.

He regarded Bukhansanseong as the last bastion protecting the royal family’s safety and guaranteeing the safety of the capital’s residents, as it would provide a place for the king to stay if war broke out.

At one point, the contraction theory of the capital gained momentum, and actual construction proceeded over several years. However, due to natural disasters and difficulties in mobilizing manpower, construction was repeatedly halted, and the contraction was never completed, effectively ending in failure.

Since the first proposal to build Bukhansanseong in 1674, after three rounds of construction debates, King Sukjong finally decided to build Bukhansanseong in February 1711.

"However, human opinions are like human faces, all different. If we wait for all opinions to agree before starting work, there will be no day of achievement. This is like the saying, ‘If you wait for your discussions to be decided, the enemy will have already crossed the river.’" 『Records of the Royal Secretariat』, 37th year of Sukjong (1711), February 9

Current Status of Daecheong Site (2020 Test Excavation) [Goyang City]

■ The Fruit of 37 Years: Construction of Bukhansanseong

King Sukjong decided to build Bukhansanseong and appointed responsible officials to establish detailed plans.

The construction was divided among the three military offices: Hunryeondogam (Training Command), Geumwiyoung (Royal Guard Camp), and Eoyeongcheong (Royal Military Headquarters).

Construction technicians were recruited nationwide, and general labor was mobilized from the capital’s residents. While the three military offices were responsible for funding, central government agencies such as Bibyeonsa (Border Defense Office), Hojo (Ministry of Taxation), Byeongjo (Ministry of Military Affairs), and Jinhyulcheong (Relief Office) also provided support.

Construction of the fortress walls began in April 1711 and was completed by October of the same year. The total circumference of the fortress reached about 13 km.

After internal facility construction, the inner fortress (Naeseong) corresponding to the central fortress (Jungseong) was completed in 1714. The fortress had a total of 16 gates, with main gates on the east, west, south, and north sides.

The palace (Haenggung), inner palace (Naejeon), and office spaces (Oejeon) totaled 124 rooms. Secret entrances, water gates to discharge water outside, and 143 fortress corridors (Seongnang) serving as guard posts and residences for soldiers were built.

The fortress also included three command posts (Yuyeong) within the fortress for the Hunryeondogam, Geumwiyoung, and Eoyeongcheong.

There were eight warehouses for weapons, military grain, and management supplies, 99 wells, and 26 reservoirs. Additionally, there were three pavilions, seven bridges, and 11 temples.

Thus, Bukhansan was reborn as a fortress area encompassing a large-scale mountain fortress.

Three hundred years after the founding of Joseon, it established itself as the guardian mountain (Jinsan, 鎭山) of the capital, defending the city and protecting the royal family and its residents.

Reference and citation: 『Castle and Kingdom』, Jo Yoon-min, -Juryuseong-

Photos: Cultural Heritage Administration, Gyeonggi Provincial Museum, Goyang City