Sunday, October 27, 2024

Nuclear Infrastructure: Yongdeok High Explosives Test Site

Deep in the western hills and mountains of North Korea lies a large fenced-off complex that occupies an entire valley. Just 7.4 km from the ancient city gate of Kusong is the Yongdeok High Explosives Test Site. (Note: it is alternatively spelled Yongdoktong.)

This facility was constructed in the 1980s and conducted numerous conventional explosive tests as part of North Korea's nuclear weapons program in the 1990s. The testing of these high explosives relates to the conventional explosive materials that make up the "lenses" within nuclear devices that compresses the fissionable core, initiating criticality and the nuclear explosion.

Kim Jong Un standing beside what has been humorously called the "disco ball", the primary stage of a nuclear device. The small circles are the locations of each polygonal, high explosive lens.

Explosive lens design and testing used to occur at the Yongbyon Nuclear Scientific Research Center but was later moved to Yongdeok once the complex became operational. As a dedicated testing and production center, Yongdeok is spread out over an area of approx. 6.3 square kilometers, with discreet facilities for the various research, design, testing, and production centers. 

It is suspected by senior US intelligence officials that Yongdeok's purpose has expanded over time, particularly since North Korea's early nuclear tests, to also become the country's primary nuclear warhead storage facility as well as its nuclear warhead assembly center.

Overview of Kusong and Yongdeok. 

There are different kinds of high explosive lens testing that can be done. These tests consist of more than just setting off a shell of explosives but involve creating an analogue core (to replicate the effects of the explosion on a real nuclear core) and recording the results in minute detail to ensure proper design and physical affects.

The simulated cores can be made up of inert, depleted uranium or even titanium. The cores are then surrounded by an explosive shell (made up of between 2 and 96 individual lenses) and the shell detonated. This compresses the metal core at temperatures so high that the core melts and reacts similarly like the real thing - just without the ensuing blast and destruction.

This kind of testing is called hydrodynamic because the core liquifies, and it has been the most common way to test this part of a nuclear device without needing to set off an actual bomb. Monitoring the implosion millisecond-by-millisecond is also energy intensive, and the entire process requires advanced technical skills.

With that said, the production sector does have a large electrical substation in the area to provide electricity and that could support modern testing (which can't be detected by outside parties). But the exact building this might occur in hasn't been publicly identified. It's also possible the tests happen in an underground test chamber.

The Yongdeok High Explosives Test Site with its main sectors highlighted.

Yongdeok can be generally divided into two main sectors, an administrative sector and a production sector which also has a residential district and is likely where testing takes place.

Yongdeok's administrative sector (2003).

Within the administrative sector are two main compounds, the administrative compound and the main security compound for Yongdeok. The administrative center will, undoubtedly, not only have offices dedicated to overseeing operations at Yongdeok but also to liaise with the multiple other nuclear research facilities throughout the country, and to develop new lenses (components, geometry, etc. to fit newer warhead designs). 


Yongdeok's production and testing area (2003).

In the production sector are the main industrial and testing areas as well as the largest housing district within Yongdeok.

There are multiple storage and handling facilities for explosive materials, assembly buildings, a large electrical substation, and other support buildings.

Yongdeok housing district (2003).

In 2003, this housing district included twelve single-story houses, eleven three-story apartment blocks, and a single-story multifamily home. These would provide space for approximately 148 families of scientists, engineers, technicians and other personnel.

Yongdeok housing district (2012).

By 2012, four additional houses were built next to the original cluster of eight homes, and a further 26 single-family houses were constructed across from the main district, bringing the total to 178 housing units in this area.

Explosives handling area (2003).

In this part of the production sector, eleven structures were protected by berms in 2003. Some are simply storage for raw materials, others for mixing and creating the final explosive mix, and still others for additional purposes.

However, the buildings within the "area of interest" box will undergo a change in the years ahead.

Explosives handling area (2012).

By 2012, the two long buildings within the area of interest had been replaced by five smaller storage structures protected by a berm. However, the activities within the long buildings may have simply been transferred to a new, single long building that was built a few meters away from the originals.

The reasons for this development likely had to do with safety or a change in the materials being handled at this site. 

Area that will eventually host an underground facility. (2003)

Yongdeok has multiple underground and hardened structures, but the most interesting and possibly largest is located at 40.030719° 125.307414°.

Two entrances are clearly visible in this 2017 image.

Sometime between 2003 and 2012, North Korea constructed this underground facility across from an unidentified set of industrial buildings. 

Normally, reviewing low-resolution LANDSAT imagery can help pinpoint a construction year as tunneling work results in large amounts of spoil (debris), which is typically dumped nearby. However, I can't find any clear signs of construction work, which means North Korea took specific care to limit what could be seen via remote observation. This probably included the use of netting to obscure the area and the removal of debris by trucks - leaving directly from the excavation site and not allowing any of it to pile up.

Underground entrance in 2021. Note, a building now covers the entrances.

The entrances are spaced ~13 meters apart and are large enough to accommodate motor vehicles. But, in 2020, the entrance was obscured by a new building. Reported on by CNN and Arms Control Wonk, the 35-meter-wide building covers the entrances but doesn't block them, and the building actually extends back into the hillside with the two entrances still very much visible. 

The purpose of the underground facility isn't publicly known. Whether it's testing, assembly, storage, or something else, the UGF continues to play an apparent central role in activities at Yongdeok.

Agricultural area (2017).

Large parts of Yongdeok are actually cultivated fields and small greenhouses, as very little cleared land in North Korea is allowed to lay fallow. The grounds next to the administrative compound are no exception. In 2017, the area held a small park but most of the land were fields. 

Agricultural area in 2023.

By 2023, a segmented garden area covering 1.2 hectares was established and three larger greenhouses were built along with two additional buildings. At the park, swimming pools were installed.

Gardens similar to this have been popping up around North Korea for the last decade or so. The food can either be grown to supplement the diets of those living in the area or grown as crops for sale (domestically or even for export), but it's most likely in this case that they're being grown to supply Yongdeok.

Probable COVID quarantine facilities (2021).

As I first hypothesized on AccessDPRK and then confirmed with NK News, North Korea built scores of COVID quarantine centers around the country. They all share the same visual signatures: external guard posts, an outer fence, and an inner wall. Sometimes they converted existing structures and other times purpose-built facilities were constructed. 

Most of these isolation centers are civilian, but some can be found at military bases. And for Yongdeok, a total of three exist, with two being built next to each other in 2021.

Detail of Site 2. 

Usually, a whole town might only have one of these secured quarantine facilities, but Yongdeok has three (the third is located at 39.993325° 125.341502°). This could be because of the national security risk posed by having a pandemic decimate the skilled population that lives and works at the site that they wanted to ensure enough treatment space was available. 

It could suggest that COVID not only hit Yongdeok but did so particularly badly, necessitating additional sites. Or maybe there's three because each one provides a larger space to patient ratio (individual rooms perhaps instead of the rows of beds at civilian facilities), so they simply needed to build more to have the required space. 

In any case, the placement of quarantine facilities at Yongdeok underscores the importance the regime places on it. Such facilities haven't been located at ballistic missile bases or even at most other military sites (including Punggye-ri). But Yongdeok has three.


In all, Yongdeok is comprised of hundreds of buildings, its own security infrastructure, and has facilities for storing and manufacturing explosive material, testing the lenses, research and development, and assembly and storage of nuclear devices. There are also enough residential units to house approximately 1,100 individuals on-site (including family members).

Yongdeok plays a critical role in North Korea's nuclear program and will for the foreseeable future. Although details of the activities at the site are unknown, satellite imagery offers us a window into one of the most secret locations in the country.

And, who knows, after Kim showed off the Kangson Uranium Enrichment Plant for the first time, maybe we'll get an official look at Yongdeok one day. 


I would like to thank my current Patreon supporters who help make all of this possible: Donald Pearce, David M., Dylan D, Joe Bishop-Henchman, Joel Parish, John Pike, Jonathan J., Kbechs87, Raymond Ha, Russ Johnson, Squadfan, and Yong H. 

--Jacob Bogle, October 26, 2024


Monday, September 23, 2024

Paraglider Training Facilities Uncovered

North Korea has nine active airborne training facilities that use jump towers to qualify paratroopers. This has been a topic covered by AccessDPRK and others in the past. However, there are also at least two dedicated paraglider training sites.

Members of KPA Unit 525, a North Korean special operations force conducting exercises in 2016 at a mock-up of the Blue House. For illustrative purposes. (KCNA)

As far as I’m aware, there hasn’t been any public reporting on the locations of these paraglider facilities. Information about the topic is scarce, and there is still a question of whether or not these two sites are part of special military operations forces or if they are training sites purely for exhibitions that take place during air shows at the Kamla and Mirim airports. 

North Korea has also disclosed the existence of civilian "parachuting clubs", but it isn't clear if the facilities described below are part of those clubs.

In any case, these two sites are part of a little understood subject within the OSINT community. Unlike an area with continual human activity, these sites were difficult to identify. After looking through imagery from dozens of different dates going back to 2010, clear paragliding activity was only noted four times at one location and three times at the second.

Because of the amount of observation it took to identify the sites due to their sporadic activity and unassuming nature, they were not included in the AccessDPRK map until the 2023 updated pro version.


Site A (Sunan-Pyongyang)

Area around the Sunan paraglider launch site.

The first site is located on a hilltop at 39.188701° 125.759280° in the Sunan District of Pyongyang, 1.4 km northeast of the Kim Jong Il Peoples’ Security University and 400 meters east of the Ministry of Social Security’s K-9 training center.

Paraglider launch point and associated facility.

The jump facility consists of a slope cleared of trees 30-35 meters wide and nearly 200 meters long at an approximate elevation of 122 meters (400 ft). There are no paved roads leading from this site, but a foot path appears to connect it to a series of buildings at 39.183573° 125.761520°, suggesting that the building complex is associated with the paragliding program.

Based on commercial satellite imagery, this site was established ca. 2015-2016 as a much smaller cleared strip which was later widened to its present dimensions in early 2021. 

Before and after image of the launch point. Images from March 2020 and February 2021.

Imagery from April 9, 2021 shows training activities taking place with six and possibly a seventh wing (canopies) visible. Four wings appear to be in the air and two or three are on the ground. Using the measuring tool in Google Earth, the wings have a span of 8-9 meters, which is on the lower end of what’s commonly used in recreational paragliding.

Paraglider activities, April 9, 2021.

Three other exercises are visible on commercial imagery from other sources between Nov. 10, 2020 and April 9, 2021.


Site B (Chwayong-Taedong)

Overview of the Taedong paraglider facility. 

Site B, located at 39.087029° 125.439573°, is the largest of the two sites. Situated south of the Chwayong Reservoir in Taedong County, it consists of a small, cleared spot on top of a hill (coordinate center) and landing fields 450 meters northeast at 39.089528° 125.443737°. This is in turn part of an even larger military complex.

Canopy seen at the launch point in 2010.

An image from Sept. 11, 2010 shows a single wing at the hilltop jump site and two more in the fields below, with a small crowd watching nearby. There is also an image on June 20, 2012 that appears to show another exercise with one wing but it is obscured by cloud cover. One further exercise may have taken place on Aug. 21, 2021 but the image quality isn’t optimal.

Canopies landing in 2010 with an onlooking crowd.

I would like to thank my current Patreon supporters who help make all of this possible: Donald Pearce, David M., Dylan D, Joe Bishop-Henchman, Joel Parish, John Pike, Jonathan J., Kbechs87, Raymond Ha, Russ Johnson, Squadfan, and Yong H. 

--Jacob Bogle, Sept. 20, 2024

Wednesday, August 21, 2024

Kyo-hwa-so No. 2 - Tongrim Reeducation Camp

North Korea operates hundreds of prisons and detention centers of various types, but only a couple dozen current and former sites have been properly identified through the use of satellite imagery and witness testimony. 

Map of known kwan-li-so (yellow text) and kyo-hwa-so (white text) prisons that remain open, with Tongrim marked out.

In this article, I want to review the Tongrim reeducation camp (properly known as Kyo-hwa-so No. 2, Tongrim). Although there is little public information available (as with the Sunchon kyo-hwa-so), I want to provide a baseline of information about its history and development (as observed by satellite imagery) to help facilitate future research.

The reeducation camp (which are known as a kyo-hwa-so) at Tongrim is one such facility that has been mentioned by defectors - although not in detail - and listed in human rights reports going back to at least 2011 (by the Database Center for North Korean Human Rights). While its exact location has not been verified by prison survivors, former guards or former local residents, through the use of commercial satellite imagery a clear candidate stands out.

Located at (39.877265° 124.727696°) 2.6 km northeast of the Tongrim train station is this complex of buildings and walled compounds. 

Tongrim and Kyo-hwa-so No. 2 locations.

North Korean authorities began arresting political opponents as early as 1947 (before the actual founding of the North Korean state), and the number of prisons proliferated through the 1950s and 1960s.

When Kyo-hwa-so No. 2 was established isn't known, but declassified low-resolution (2-4 ft) imagery from the KH-9 satellite shows the site going back to at least 1973, meaning the prison was established some time before then. Earlier images from the USGA's EarthExplorer program exist but their resolutions are too low to make any clear determination.

Kyo-hwa-so reeducation camps are typically used to house "redeemable" prisoners. Following a period of hard labor and ideological “training”, prisoners may be released. The larger kwan-li-so political prison camps house more serious offenders and prisoners are held for a longer period of time or even for the rest of their lives.

All known kyo-hwa-so and kwan-li-so prison camps use forced labor. From mining coal to making uniforms and even fake eyelashes, proceeds from prison labor provides millions of dollars in revenue to the state each year. 

Having said that, the exact forms of forced labor used at Tongrim aren't known. However, the prison sits at the base of a stone quarry, so it's logical to assume that the prisoners are used to extract stone (among other activities). 

The earliest high-resolution commercial imagery of Tongrim comes from 2005. 

Kyo-who-so No. 2, Tongrim. Image of prison and quarry from May 2005.

The prison complex can be separated into three main sections: administrative, prisoner barracks, and the quarry.

Unlike the larger kwan-li-so political prison camps, the area around Kyo-hwa-so No. 2 isn't surrounded by a perimeter fence. The prison and quarry extend about 1 km along a small mountain valley, with three sides flanked by rocky terrain. But only the prisoner barracks have any sort of fence or wall around them.

Detailed view of the main prison area from 2005.

The main administrative and support area has a number of different buildings. What the purpose of each building is can't currently be known with certainty, but it will likely have a main administrative building, a dining hall, a building for ideological and political training, as well as a guard barracks and a vehicle storage and repair facility. 

The administrative area also has a ~270 sq. m. building that is surrounded by a wall. This building is similar to one described at the former Kwan-li-so No. 22 in Hoeryong as being an interrogation center. I will discuss this in more detail near the end of the article.

The prisoner section consists of a walled compound that occupies 1.56 hectares and has nine buildings inside it. The main gate is protected by a guard building and a security tower. There are also prisoner barracks and workshops within the walled perimeter.

The guard building is approximately 180 square meters in size. The prisoner barracks is a large, single-story L-shaped building with approximately 950 sq. m. of floor space.

Based on witness testimony from other prisons, the prisoner barracks will have a number of rooms that hold prisoners and other rooms such as a latrine and guard room. It may also have a dining room, interrogation room, a medical room, and other offices or closets; although, those could also be housed in other buildings within the compound.

In terms of the prisoner population, in 2005 it is unlikely that Tongrim held more than 2,500 individuals.


Tongrim quarry, 2005.

Attached to the prison complex is a rock quarry. The primary quarry is roughly 400 meters long. A rail spur coming from the main Pyongui Line (2.7 km south of the quarry) enables loading and transport of the quarried materials. 

In 2005, the rail line, an explosives storage area with two storage buildings, and a cluster of six nearby support buildings and two greenhouses existed. 

Additional support structures and material transport infrastructure existed within the quarry site itself.

Tongrim prison in 2010.

By 2010, the workshop area by the prison's administration, noted in the 2005 image, had conclusively been converted into a barracks, and a perimeter wall was erected around the site. The new building within the perimeter wall has approximately 600 sq. m. of floor space and the wall enclosed an area of nearly 3,800 sq. m. This addition may have provided space for up to 500 new prisoners or to create an area to segregate a new class of prisoners among the existing population (segregated by sex, severity of the crimes, or perhaps by songbun class).

An entrance gate and guard tower were added, as well as a smaller tower in the northernmost corner of the new compound.

At the main prisoner compound, a new 26-meter-long building was constructed.

Between 2005 and 2010, little changed at the quarry.

Tongrim prison in 2012.

The main change at the prison between 2010 and 2012 is that the perimeter wall of the newer compound was extended northward to enclose two 30-meter-long greenhouses and a connected support building which the prisoners operate. Whether the food is grown for the prisoners, for the guards, or to sell can't be determined.

Based on the imagery available, the foundations for the greenhouses were laid in April 2010 and so they were likely completed in that year.

Tongrim prison in 2014.

By 2014, a new ~120 sq. m. building had been constructed within the main prison compound. 

In the administrative area, an unidentified building had its roof replaced (now covered in blue tiles). The removal of the old roof is actually visible in the 2012 image, but it's not annotated.

Tongrim quarry, 2014.

At the quarry, by May 2014 the number of support buildings fell from six in 2005 to just three. An area of active quarrying is also clearly visible at the southern end of the quarry. This location has been the main site of activity since 2005.


Tongrim prison in 2019.

In the main prison compound, between 2014 and 2017, the 26-meter-long building that was constructed ca. 2010 had been razed. And between 2017 and 2019, the ~120 sq. m. building that was built ca. 2014 was also razed.

Additionally, the greenhouses in the small walled compound were also removed between 2018 and 2019.

The 2014 to 2019 timeframe represents the first period of major demolition at Tongrim. 

Tongrim prison in 2021.

By 2021, the extended perimeter wall at the smaller compound had been removed, reducing the walled area back to its original size.

In the main prisoner compound, the grounds have become overgrown with vegetation, possibly a crop.
This would not be unusual as North Korea attempts to cultivate every potential area it can from prisons to military bases. And, yet another building has been razed (occurring between Nov. 2019 and February 2020).

The workshop buildings, however, have started to show signs of disrepair, with fairly extensive roof damage visible in 2021. (More limited roof damage can be seen as far back as 2019.) Buildings at other prisons and industrial areas routinely show damaged roofs, but it can often serve as an indicator of the level of activity at and importance of a particular structure or facility. 

Regardless of the damage at the workshops, the rest of the prison complex appears to be well maintained. 

Tongrim quarry in 2021.

At the quarry, activity levels have declined, and more buildings have been demolished since 2014.

The storage buildings that held the explosives used at the quarry have been removed. And a total of three support structures within the quarry were also razed. 

The area of active quarrying also appears to have moved to a small area near the loading facility, with no new changes since ca. 2019 to the southern site mentioned previously.


Tongrim prison in 2024.

The biggest change in 2023-24 was the total demolition of the workshop buildings within the main prison compound. Whether this is a permanent situation or if they will rebuild a new one, only time will tell. But it follows a multi-year trend of demolitions.

Tongrim quarry in 2024.

The demolition trend extends to the quarry site as well, with the railway building being razed in 2023-24. At this part of the quarry, only two of the eleven or so nearby support buildings that existed in 2005 still stand today, and the explosives storage site also remains closed.

Importantly, the prison's rail connection to the main Pyongui Line (2.7 km south of the quarry) was removed ca. 2020-21, and the last section of rails were removed from the quarry in either 2023 or early 2024.

A comparison of images from 2010 and 2024 (below) paints a fairly clear picture that quarry operations are being wound down if they haven't yet been stopped entirely.

A wide view of the quarry area in 2010.

In 2010, operations at the quarry were ongoing and numerous support buildings existed. The brightness of the quarry and rock faces is indicative of activity levels; the brighter the more recent.

A wide view of the quarry area in 2024.

As mentioned, by March 2024 most of the buildings have been removed, the rail line is gone, and much of the quarry itself has become covered in dirt and vegetation, indicating little to no recent activity.


I want to take the opportunity to also talk about some other features and changes to the prison that deal more directly with people's lives.

As mentioned near the beginning, Kyo-hwa-so No. 2 has a separate walled building in the administrative area. The building is ~26 meters long and is surrounded by a wall that is positioned quite close to the building itself. It has its own entry gate to the south and there is a guard tower on the northeast corner of the wall.

Walled building in 2024.

The building is similar in its size and location within the prison complex as another building that was located in Kwan-li-so No. 22 in Hoeryong. Before the prison was closed in 2012, a former guard attested that the building was used to interrogate prisoners and even torture them.

Based on the available visual and contextual evidence, I believe that this building may be where prisoners are interrogated at Tongrim. 

According to the UN's Commission of Inquiry on Human Rights in North Korea, "torture is an established feature of the interrogation process", with many prisoners dying during the process or suffering from permanent injury. 


Also of note, despite the demolition of other buildings around the prison, security has been tightened around the main prisoner barracks.

In December 2022, the barracks was surrounded by a tall wall as the primary physical barrier.

Main prison compound in 2022.

But between 2023 and 2024, a fence was erected around the barracks, making freedom of movement even more limited, and effectively reducing the overall size of the compound in which prisoners could walk around in by more than half (to 0.6 ha, down from 1.56 ha).

Main prison compound in 2024 with new fence outlined.

The last activity at Tongrim I want to discuss is the visibility of a large number of prisoners on the March 8, 2024 image. Catching individuals on satellite is uncommon and one of the most cited examples, at Chongjin in 2018, showed but a handful of individuals. 

But in the below image, over 100 individuals are visible and more can be seen walking along the main road nearer the quarry. And this is just the most recent example, as prisoners can be seen in several previous images on Google Earth.

It can perhaps be easy when viewing sites through satellite to forget that the places we look at are connected to human beings living real lives. Whether it's a school, factory, prison, or any other place, the pixels we're seeing are comprised of the lives, struggles, work, and happiness of other people.

Unfortunately, the one's we're seeing below are made up from a regime that commits among the worst human rights abuses in history and does so through the torment of countless individuals, many of whom committed no crime that would be recognized anywhere else in the world.

Prisoners can be seen on satellite in multiple locations, 2024.

North Korea has hundreds of penal facilities of numerous types and sizes with Kyo-hwa-so No. 2 making up one small part of a system that imprisons over 150,000 at any given moment. And through this review, we can see that North Korea's detention system continues to be dynamic, with new buildings constructed, old buildings removed, and people marched from place to place engaged in forced labor throughout all seasons.

Kyo-hwa-so No. 2 also provides some insight into changes within the overall system.

Although none of the prisoner barracks or security installations of Kyo-hwa-so No. 2 have been removed, the removal of multiple workshops and other support buildings throughout the complex suggests that the prison is undergoing a reorganization and may be preparing to be downsized, as occurred at Kyo-hwa-so No. 88 in Wonsan, and its human "resources" reengaged in other types of labor. 

Indeed, DailyNK reported in 2017 that Tongrim was actually converted into an orphanage. However, that use is hard to reconcile with the visible security features at the site such as the new fence erected around the barracks, and the fact that dedicated orphanages already exist. If there was such a change at Tongrim, then it is an orphanage in name only. In practice, it would serve more as a juvenile detention facility where the children are treated little better than adult prisoners (and also used for forced labor).

These changes highlight the need for continued observation of Tongrim but in the end, witness testimony will be required to answer some of these questions. Ultimately, it is up to the North Korean government to begin to uphold its obligations under domestic and international law, to cease the operation of its vast constellation of prisons, to allow independent international observers to visit all prisons to document any human rights abuses, and to place those responsible for crimes against humanity at the hands of justice.


Other prison reviews by AccessDPRK:

1. Review of the Sunchon Kyo-hwa-so (2024)

2. Is Wonsan Prison No. 88 Closing? (2021)

3. Chongjin Prison Camp Update (2019)

4. Prison Camp No. 22 Today (2018)

I would like to thank my current Patreon supporters who help make all of this possible: Donald Pearce, David M., Dylan D, Joe Bishop-Henchman, Joel Parish, John Pike, Jonathan J., Kbechs87, Raymond Ha, Russ Johnson, Squadfan, and Yong H. 

--Jacob Bogle, Aug. 21, 2024 (edited Aug. 22)

Wednesday, July 24, 2024

The Development of North Korea's Northern Border Wall

Ever since the mass defections and rise in illegal trade caused by the 1990s famine, North Korea has tightened its grip on border security with increasing severity, but its northern border was still far from impenetrable. 

Despite fences and guard patrols, along with inhospitable terrain and weather on both sides of the Yalu and Tumen rivers, plus China's repatriation policies, total defections could reach several thousand each year. While most defectors remain in China in hiding, between 1,000 and 2,000 would make it to South Korea annually since about 2001.

But as the COVID pandemic spread, North Korea was not only faced with a possible existential threat due to the poor state of the country's healthcare system, but it was also faced with an opportunity - to use the pandemic as an excuse to finally (and completely) close down the border.

In the intervening four years, the physical barriers associated with the "border wall" were built, altered, and now appear to be undergoing a final series of changes.

In this article, I will lay out the development and current state of North Korea's anti-pandemic border measures now that the threat of the pandemic has waned, and as Pyongyang seeks to at least partially reopen its borders. 

3D render of a section of renovated border fence. This section features a levee, a double-row of fencing, guard posts, and a border guard garrison is in the background (right). Created by Nathan J. Hunt for AccessDPRK.


As far as I'm aware, I was the first person to note (with the aid of satellite imagery) that North Korea was increasing its border security with a Spotlight Report published by AllSource Analysis back in April 2021.

The report highlighted changes around the border town of Hoeryong, particularly noting an increase in the number of guard posts and the now ubiquitous primary and secondary lines of fencing.

Chronologically, however, one of the earliest examples of improved security following the border's closure in January 2020, was the addition of guard posts in Ryongchon County (south of Sinuiju) in September 2020.

Location of new guard posts built in 2020 along a section of older border fence in Ryongchon.

However, according to DailyNK reporting, the order to build a new border fence across the entire border wasn't issued by Kim Jong Un until February 2021. 

The addition of new guard posts may have been a separate order followed by a new (Feb. 2021) order to build the border fence, or perhaps the earliest order may not yet have come to light. Regardless, the timeline of increased border security was not uniform, with some areas undergoing construction sooner and others delayed. But by 2021, work was underway along the full North Korean border with China and Russia.

As mentioned, the first activity seen was the installation of thousands of small guard posts. Most were along the existing border fences, but some were placed in the middle of fields or atop river levees. In total, I have estimated that up to 15,000 guard posts dotted the landscape at the height of the pandemic.

Following the installation of numerous guard posts, secondary fence was then constructed behind the main border fence. The secondary fence was located anywhere from just a few meters behind the main fence to several hundred meters behind, and it cut through agricultural fields, forests, spanned rivers, and even incorporated the boundaries of factories and houses.

This secondary fence, based on a range of tourist photographs taken from the Chinese side of the border, was built out of either wood or reeds, depending on the raw materials available in each locality. 

Annotated photo of the DPRK border at Namyang showing the main border fence and the secondary fence made out of reeds. Annotations by AccessDPRK. Photograph comes from Weibo, March 2023.


To accomplish the work, construction units logged local forests and built temporary work camps in multiple locations along the border. 

Area of interest near Chang-ni in 2020, prior to logging.

Area of interest showing logging activities in 2022.

Timber piles for fence construction in Chunggang County, 2022.

Elsewhere, logs being staged for use in fence construction can be seen. In the above example, that area had simply been empty previously. No logging or storage activity existed prior to this event.

The work camps, as seen below, are standard for any large-scale construction project such as at the major residential projects underway in Pyongyang. 

One of multiple temporary, small worker's camps along the Taehongdan section of the Sino-DPRK border.

One of the temporary worker's camps in Musan.

Given the logistics of building a border fence across more than 1,000 km of highly variable terrain, instead of having a single centralized worker's camp, the camps (with their housing, workshops, and other facilities) are dispersed; with dozens of them along the border, each housing only few dozen to a few hundred workers. 

Worker's camp near Onsong. Numerous small buildings can be seen in October 2022.

The Onsong camp had been removed by May 2023 and the meandering secondary fence completed.


Following the addition of guard posts to tighten security and the wooden secondary fence that served to cut off access to the areas under construction, any original border fencing was then demolished section by section.

The next steps taken were to reenforce, rebuild, or newly construct flood barriers in places prone to flooding, and then building the new fence on top of those levees - with each province (and likely each county) responsible for providing most of the manpower and materials needed within their jurisdiction.

On a bend of the Tumen River, 2 km away from the Onsong worker's camp, a new levee was under construction in 2022.

By May 2023, the levee was largely completed, and the new electrified fence was placed on top. However, some soil grading activity was still ongoing. 

In at least one area, in Rason, a new quarry was opened to provide the materials needed for local levees. 

Rason quarry, with both the new main fence and secondary fence visible.

New fences were also constructed on hills and mountainsides, areas that were often left poorly controlled prior to COVID and that served as routes of defection.

The previous border fence was just a single row of barbed-wire fencing with guard posts that were only concentrated near populated areas and areas where defections were less physically difficult (open fields, narrow parts of rivers, etc.) Guard posts were often 1 km apart or even farther, and the wide reservoirs along the Yalu lacked fencing in general. 

The main border fence now comprises two rows of tall fence, allegedly electrified, with a patrol road along it. And the secondary fence appears to have become a permanent part of the system as well. 

Guard posts are considerably closer together and can be found along the entire length of the border - even in remote areas. Guard posts are positioned on both the main and secondary fences. Fencing was also added to the previously unprotected reservoirs (such as the Sup'ung Reservoir) and electronic surveillance infrastructure was improved.

Construction of the new fence was carried out by border guards, local labor brigades and, due to the immense manpower requirements, military units from XI Corps (Storm Corps) were also used. However, the same manpower requirements that necessitated the use of the military to help construct the border fence also temporarily drained the readiness of the corps.

After first being fortified with additional guard posts, the fence path in this area was moved further inland to follow an existing road. 

Between 2021-2023, fence paths were adjusted to improve local security and as better paths were identified during construction. 

Along with the fences and guard posts, over 400 border guard garrisons now dot the landscape. Most of the garrisons existed before COVID and many had already been renovated ca. 2016, but new ones were still constructed, and other changes were made to existing sites.

Example of a border guard garrison.

However, there have been changes to the level of security seen earlier on in the fence's development. What I would describe as being overkill in the number of guard posts (and thus guards needed) has been relaxed, with many redundant positions removed

Nonetheless, the northern North Korean border has become one of the most well-secured civilian borders in the world. Presently along the northern border are over 400 guard posts, 10,000-13,000 guard posts, and approximately 2,100 km of primary and secondary fencing has been identified by AccessDPRK.

Combined with increased security on the Chinese side of the border and enhancements to the DPRK coastal fence as well, it is unlikely that defection rates will return to previously seen levels anytime soon. (Only 196 made it to South Korea in 2023.)

Animation showing the development of a section of border fence from July 2020 to October 2023.

3D render of the same section of fence with the border guard garrison building shown on the left. Created by Nathan J. Hunt for AccessDPRK.


Note: if you'd like to learn more about how North Korea's border closure has impacted the lives of average North Koreans, check out this in-depth report from Human Rights Watch which I assisted with.

I would like to thank my current Patreon supporters who help make all of this possible: Alex Kleinman, Amanda Oh, Donald Pearce, Douglas Martin, David M., Dylan D, Joe Bishop-Henchman, Joel Parish, John Pike, Jonathan J., Kbechs87, Raymond Ha, Russ Johnson, Squadfan, and Yong H. 

--Jacob Bogle, 7/23/2024