Namhansanseong - Fortress

Namhan Mountain Fortress features multiple examples of Korean fortress wall construction techniques. Yeojidoseo (黎地圖書), a report on the geographical circumstances of Namhan Mountain Fortress, describes the site as a "fortress made in heaven." The interior is flat, while the outside is steep, like a crown atop a mountain. The Annals of Taek Village (擇里志) also notes: "Namhan Mountain Fortress is low and shallow on the inside but high and steep on the outside. The Qing forces were unable to bring their weapons to bear and the fortress never fell during the Manchu Invasion of 1636. King Injo only left the compound for lack of food and the fall of Ganghwa Island." The fortress wall, more than 12km in circumference, follows a rugged terrain over 500 meters above sea level. The geographical position makes the fortress difficult to attack, even with many troops. The compound inside the walls is broad and flat, while water is plentiful: more than 80 wells and 45 lotus ponds. With a proper supply of food, tens of thousands of soldiers could be kept here. Structurally, Namhan Mountain Fortress was equipped with the necessities for an installation of its kind in the Joseon Period. Besides the main wall are two outer walls (Bongamseong and Hanbongseong). Two observation towers are on the south side of the fortress. The main wall are protected by 5 extended outer works (甕城 ongseong), and more than 20 reinforced works were installed. Four main gates and 16 hidden gates (暗門 ammun, a gate hidden from outside view, used to secretly transport weapons, food, other items, and people without letting the enemy know) were built into the walls. On top of the main fortress wall is a low, shallow wall (=parapet) called yeojang (女墻). This feature makes the overall wall appear taller from outside and blocks the view inside. The yeojang consists of 1,940 merlons with apertures for the defenders to shoot through. Some of the aperture are pointing straight out for shooting at targets in the distance, while others slant downward to shoot at enemies close to the fortress wall. Inside the fortress wall were 125 guardhouses (軍鋪 gunpo), with caches of salt and charcoal buried in more than 90 spots between them. Normally, provisions and military supplies were maintained inside the fortress as well. The main wall at Namhan Mountain Fortress used stones that were first employed in the building of Jujang Fortress during Unified Silla. The outer wall was constructed at different times than the main wall was. Thus, one can find wall construction methods used from the 7th century through the 17th century. Such a variety of styles at one location is an important asset for understanding how wall construction developed in Korea. These days, many TV dramas are filed with the walls as a backdrop, and they attract large numbers of tourists each year. The Annals of Namhan (南漢志) details the scale of Namhan Mountain Fortress: "The inner circumference is 6,290 paces (17.5 li), while the outer circumference is 7,295 paces (20 liplus 95 paces). These figures would convert to 7,854 meters and 9,108meters, respectively assuming one Korean foot (ja) is 20.81cm long. There are 1,940 merlons on top of the fortress walls, five extended outer works, 16 hidden gates, 125 guardhouses, and 5 command posts (將臺). Three different methods can be used to measure the circumference of the wall, depending on the reference point: (1) the base (基壇部) of the outside wall, (2) the inside base (基底部) of the yeojang, or (3) the center line of the yeojang top. The simplest and most common way is basing the measurement on the center line of the yeojang top, which would make the main wall (without counting the outer wall and ongseong) 7,545 meters long and the area within the wall 2,126,637 square meters. Add the auxiliary facilities and the total sale comes to 12.356 square kilometers.

This extended outer work is placed around the front of a gate for added protection. Invaders have to penetrate the ongseong to reach the gate, and defenders on top of the wall are able to fire down on the intruders from three directions.

Namhan Mountain Fortress has five ongseong in total, three on the South Wall, one on the East Wall (Yeonjubong Ongseong) and one on the North Wall (Janggyeongsasinji Ongseong).

The defensive walls of Namhansanseong largely consisted of two parts, the Bonseong or Wonseong (fortress body), which was built during the reign of King Injo (r. 1623-1649) of the Joseon dynasty, and the Oeseong (extended defensive wall), which was built during the reign of King Sukjong (r. 1674-1720), also of the Joseon dynasty. The fortress body generally covers the area protected by the old fortification (called the Jujangseong), which was originally built during the Silla period and renovated during the reign of King Injo, whereas the extended part of the fortress consists of the Bongam Extended Defensive Wall, Hanbong Extended Defensive Wall and Sinnam Outwork. The newer walls were designed to exploit the distinct physical features of the mountain ridges branching out in an east-west direction from the main ridge of Cheongnyangsan Mountain, which runs from south to north.

The construction of the extended defensive wall started in the third month of 1686, when Yun Ji-seon (1627-1704), then the Yusu of Gwangju, proposed the reinforcement of the fortress body by building an Bongamseong (auxiliary fortification), and provided labor drawn from the Sueocheong Army Corps Headquarters, along with financial support of about thousand-seok of grain (one seok is equivalent to approx. 180 liters). The construction work took fifty days to complete, resulting in the creation of a 300-meter-long wall with 294 merlons, 4 auxiliary gates, and 15 guard towers. A record of the construction of Bongamseong was found engraved in regular script on a natural stone used in the fortification . The Hanbong Oeseong (second auxiliary fortification) was built in 1693 under the supervision of O Si-bok, then serving as the Sueosa. Unlike the Bongam Extended Defensive Wall, which completely encloses the mountain top, the Hanbong Extended Defensive Wall was designed to provide a direct, safe passage to the summit of Hanbong Peak. The fortification was originally 851 feet in circumference, and had 227 merlons and one auxiliary gate. Part of the fortification was demolished in 1705 at the command of a Qing envoy, but the entire fortification was renovated in 1739 by Jo Hyeon-myeong, then the Sueosa, in order to create a 895-feet-long wall and 272 merlons. This was also the year that his successor Min Jin-hu continued to renovate the fortification, placing two batteries on Bongamseong, along with a casemated embrasure, so that it could join the gun on the Janggyeongsa Outwork in a pincer attack against an enemy assault. The renovation project led by Min Jin-hu in 1719 created a fortified area with a circumference of 743 feet, complete with 238 merlons and a casemate, which are now called the Sinnam Outwork and Namgyeokdae, respectively. Built on the summit of Geomdansan Mountain (534 meters), about 2.6 kilometers south of the fortress body, the renovated fortification was occupied by Qing forces during the Byeongjahoran, and was used to launch an artillery bombardment against the defending Joseon forces. The extended fortification had two observation towers in 1753, completing the system of defense of the temporary royal palace, which would eventually play a key role in defending the capital of the Joseon Dynasty.

It appears that Seomun (West gate) was part of the original fortress and it was restored in 1799, and renamed "Right Side Gate" since it was on the right when facing south from the secondary palace. In 1637, King Injo and the Crown Prince went through this gate to surrender to the Manchus. The slope on the west side of the fortress was too steep for provisions to come through, but those were easily sent through from Gwangnaru or Songpanaru ferry landings.

Bukmun (Northgate) was used to launch attacks from the fortress during the Manchu siege. According to the record, 300 soldiers went through the gate to attack the Manchus but fell into a trap and were annihilated in the greatest fight and loss of troops during the siege. During the rebuilding of 1779, the gate was renamed Jeonseungmun or "Battle Victory Gate" with the meaning to never forget the loss. The gate is thought to have been built in 1624.

"Jangdae" refers to the a 2-story pavilion used as a lookout for commanders to direct the battle. Originally, Namhan Mountain Fortress had five (including ones in each of the four directions), but today only Sueojangdae (守禦將臺) remains.

The greater part of the defensive walls of Namhansanseong is studded with parapets - low defensive walls with rectangular gaps or indentations placed at intervals to allow troops to fire arrows or other missiles from within the defenses without exposing them to enemy attack. The parapets of Namhansanseong are characterized by an upper structure built with bricks laid on stone bases.