North Korean artillery has been considered a serious threat to Seoul for decades due to its extensive deployment along the DMZ—the demilitarized zone that has been in place since the 1953 Korean Armistice Agreement. The origins of this threat can be traced back to the 1990s, when North Kora began prioritizing the positioning of long-range artillery and rocket systems capable of striking the South Korean capital. The perennial threat of turning Seoul into a “sea of fire” has long burdened US and South Korean policymakers, who have grappled with the challenge of managing this risk while avoiding escalation on the Korean Peninsula. The estimated casualties that North Korean artillery could inflict on South Korea range from approximately 4,500 to over 200,000, depending on the scale and duration of the bombardment. Pyongyang has leveraged Seoul’s apparent vulnerability through brinkmanship diplomacy, extracting concessions by threatening artillery strikes on the south. However, is North Korea’s artillery capability truly the existential threat it’s often portrayed to be? According to my research, it is not. While North Korea’s artillery remains a factor, it should not be exaggerated. In fact, there are more immediate threats that US and South Korean policymakers should focus on to ensure national security and the overall credibility of US extended deterrence.

To evaluate the potential impact of North Korean artillery in a full-scale conflict, I have used the 2010 Yeonpyeong Island shelling incident—one of the most significant military confrontations since the Korean War, in which North Korea bombarded the South Korean island, resulting in four deaths and heightened tensions—as a key reference point. In that incident, North Korea launched approximately four hundred rounds, with only eighty reaching their intended targets and 320 falling into the sea. Of the eighty rounds that landed, twenty failed to detonate. This means that only about 15 percent of the rounds successfully hit their targets and detonated as intended. Notably, this attack was carried out by North Korea’s elite artillery units, using some of their best-maintained munitions. However, due to inadequate storage conditions and a lack of humidity control caused by electricity shortages, the performance of these munitions was likely compromised. This raises serious doubts about the overall reliability of North Korean artillery in a full-scale conflict, even when operated by the most capable forces.

By extrapolating insights from the Yeonpyeong Island shelling incident to a larger scenario involving North Korea’s 170-millimeter self-propelled artillery and 240-millimeter multiple-launch rocket systems stationed near the DMZ, we can better understand the potential threat to Seoul. While North Korea is estimated to have around 8,500 field artillery pieces and 5,100 multiple-launch rocket systems, only about one hundred 170-millimeter self-propelled guns and two hundred 240-millimeter multiple-launch rocket systems are positioned within range to directly target the South Korean capital. Based on this, the following outcomes can be reasonably expected. In a worst-case scenario, the 170-millimeter artillery could fire approximately one hundred shells, while the 240-millimeter rocket launchers might launch around 4,400 rockets in an initial strike on Seoul. However, the likelihood of a second volley is extremely low, as South Korean air forces would seek to neutralize the North Korean artillery after the first barrage is released. Based on the statistics from the Yeonpyeong shelling incident, approximately forty-three artillery rounds and 1,870 rockets would reach Seoul. Considering Seoul’s vast area of 605 square kilometers and the lethal blast radii for the two weapons—fifty meters for 170-millimeter artillery and seventy meters for 240-millimeter rockets—the maximum total affected area of 29.12 square kilometers, including nonresidential zones such as fields, amounts to 4.8 percent of the city. Given that a portion of the shells that land would be duds, the actual exploded shells would impact less than 4.8 percent of Seoul’s area. Furthermore, as demonstrated during the Yeonpyeong bombardment, North Korean artillery has difficulty penetrating concrete structures. With most buildings in Seoul constructed from reinforced concrete, damage would be minimal, particularly if civilians take shelter indoors. Considering the likely further deterioration of North Korean munitions over time, the actual threat posed to Seoul is probably even lower. In short, the prospect of Seoul becoming a “sea of fire” is extremely unlikely.

A more immediate threat is posed by North Korea’s unmanned aerial vehicles (UAVs), as demonstrated in the 2022 North Korean UAV airspace intrusion incident, in which five North Korean UAVs entered South Korean airspace, evading interception despite the deployment of superior South Korean air assets. These UAVs, if deployed to target critical infrastructure such as power grids, nuclear reactors, or airfields, could cause significant disruptions. The failure to intercept these UAVs highlights the growing need for the United States and South Korea to focus on bolstering defenses against North Korean UAVs, which present a more pressing and realistic danger than artillery.

Another significant threat from North Korea is its advancing missile and nuclear capabilities. Should Pyongyang successfully miniaturize nuclear warheads and develop multiple independently targetable reentry vehicle technology, it could undermine the credibility of the United States’ extended deterrence in the region. By doing so, North Korea could escalate its brinkmanship diplomacy, weakening the US-ROK alliance and sowing doubts about the US commitment to defend South Korea. To counter this, the United States and South Korea must establish clear red lines for North Korean behavior and ensure that Pyongyang understands that any nuclear aggression will result in a decisive response. The recently signed Trilateral Security Cooperation Framework between the United States, Japan, and South Korea provides a platform to reinforce these deterrent measures.

In light of the above points, US and South Korean policymakers should reevaluate the actual threat posed by North Korean artillery. While it is important not to be complacent, it is equally critical not to overestimate North Korea’s artillery capabilities. Instead, focus should shift toward addressing more immediate threats, such as North Korean UAVs breaching South Korean airspace and the diminishing credibility of the United States’ extended deterrence in light of North Korea’s advancing missile and nuclear capabilities. By prioritizing these areas, the United States and South Korea can maintain a more balanced and effective defense strategy, avoiding policy distortions caused by North Korea’s use of artillery threats to hold Seoul hostage, while addressing the genuine risks that undermine regional stability.

Dr. Ju Hyung Kim is a defense analyst at a South Korean defense think tank and is currently in the process of transforming his doctoral dissertation, titled “Japan’s Security Contribution to South Korea, 1950 to 2023,” into a book.

The views expressed are those of the author and do not reflect the official position of the United States Military Academy, Department of the Army, or Department of Defense.

Image credit: Stefan Krasawski