
What would a military conflict on the Korean Peninsula look like? To many, this question might trigger a severe case of apocalyptic anxiety, where, on the one hand, we assume that the Democratic People’s Republic of Korea (DPRK) is willing to embrace Götterdämmerung-like catastrophic violence to defend its Stalinist regime, whereas, on the other hand, we seem to be incapable of genuinely fathoming the carnage any military conflict between Seoul and Pyongyang would cause.

One explanation for this may be that estimates of casualties and physical destruction on the Korean Peninsula (and possibly Japan) under any war scenario are so exceedingly high. Should Pyongyang live up to its threat of turning Seoul into a “sea of fire,” casualties in the larger Seoul metropolitan area alone may surpass 100,000 within 48 hours, according to some estimates, even without the use of North Korean weapons of mass destruction. The U.S. Department of Defense assessed that a Second Korean War could produce 200,000-300,000 South Korean and U.S. military casualties within the first 90 days, in addition to hundreds of thousands of civilian deaths.

I will briefly outline how a war between North and South might unfold. My analysis will not try to sketch out all possible war scenarios and instead focus on one hypothetical sequence of events: A conventional North Korean surprise attack across the Demilitarized Zone (DMZ) following an assessment by the supreme commander of the Korean People’s Army (KPA) that a preemptive strike against nuclear weapons facilities is imminent.

This scenario is based on four tentative assumptions. First, despite treaty obligations laid out in the 1961 Sino-North Korean Treaty of Friendship, Cooperation, and Mutual Assistance, China will not come to the defense of North Korea in the event of a North Korean surprise attack on the South. Second, Pyongyang will not use nuclear weapons to destroy Seoul. Third, North Korea — even if it has the capability — will not fire an intercontinental ballistic missile (ICBM) against a target in the continental United States. Fourth, the United States will not fire nuclear missiles against Pyongyang.

The core belief underlying these assumptions is that North Korea’s supreme leader, Kim Jong-un, is primarily motivated by regime survival and as a consequence would not unnecessarily expose Pyongyang to a U.S. nuclear attack and immediately escalate the conflict to the nuclear level as long as he assumes that he can retain a second-strike capability. Furthermore, under this scenario, Kim assumes that South Korean and American war plans do not entail his removal from power (which, not only due to recent comments by U.S. President Donald Trump, may be a flawed assumption).

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A possible explanation for the dictator’s hypothetical decision to invade the Republic of Korea can be found below. For now it suffices to say that North Korea could dedicate 700,000 out of its approximately one million-strong ground forces, 8,000 artillery pieces, 2,000 tanks, 300 aircraft, over 400 surface warships and about 50 submarines to an invasion of the South. Given that all of the matériel mentioned above is located within 100 miles of the DMZ, it is assumed that such an attack would not require large-scale redeployment of military assets and could be launched within three days after the marching order is given by Kim Jong-un.

The primary objective of the invasion would be to seize Seoul and hold it as long as possible while inflicting maximum damage on the South’s civilian and military infrastructure. Capturing even a portion of the city would not only be an important propaganda victory, but also guarantee the most costly and casualty heavy form of modern warfare to occur on South Korean soil–urban combat.

In order to seize the South’s capital city, North Korean forces would advance along a 75 mile wide front down the Chorwon, Kaesong-Munsan, and Kumhwa corridors. The main thrust would likely come from either the Kaesong-Munsan route, north of Seoul, or the Chorwon valley to the northeast. Speed would be of the essence for the KPA. Given the peninsula’s mountainous terrain, the corridors could quickly become death traps for the KPA if exposed to South Korean and American airpower and precision-guided munitions fired from heavily fortified ROK positions along the invasion routes.


The attack would be preceded by strategic cyber strikes against Republic of Korea (ROK) and U.S. command and control facilities (and critical infrastructure in Seoul) as well as an artillery barrage. North Korea has about 500 long-range artillery systems, including 170 millimeter Koksan guns, 122 millimeter launch rocket systems with extended range, as well as 240 and 300 millimeter systems, within range of the Seoul metropolitan area. The Diplomat’s Second Korean War scenario assumes that the KPA would devote the majority of its long-range artillery assets to counterforce attacks against ROK and U.S. military facilities along the invasion routes. A portion of artillery systems would be used for countervalue attacks against civilians and economic infrastructure in the Seoul and its suburbs.

Assuming that around 70 percent of long-range systems are operational, and factoring in gun crew training (assumed to be mediocre at best) as well as a 15 to 25 percent detonation failure rate of KPA artillery shells, ROK /U.S. forces and civilians in Seoul would still be exposed to a deadly barrage that could kill thousands if not tens of thousands in the first hours of the conflict before KPA artillery is either taken out or has to withdraw due to the fear of being destroyed by counterbattery fire. This analysis also assumes that the KPA will fire chemical shells into Seoul (the North’s chemical weapons stockpile includes mustard gas, sarin, and VX nerve agent) further increasing the chances of mass civilian casualties. The psychological impact of chemical warfare would be immense: One chemical shell exploding in Seoul would be enough to create a civilian mass panic and delay ROK/U.S. forces’ ground movement.

The much debated casualty rate in Seoul will above all depend on the speed of ROK/U.S. counterattacks and the concerted evacuation efforts of Seoul’s civilian authorities.

In addition to artillery strikes, North Korea would launch hundreds of ballistic missiles against civilian targets. (The Diplomat analysis assumes that given the purported inaccuracy of most North Korean ballistic missiles, KPA leadership will use the majority of missiles in countervalue attacks.) The North would not launch its entire ballistic missile arsenal in the initial attack but retain a strike capability for future use. Nevertheless, a salvo of hundreds of conventional ballistic missiles would not only overwhelm ROK and U.S. ballistic missile defense, but would also increase the chance of one of the KPA’s estimated 150 chemical warheads reaching its target — presumably against Seoul. (Other targets might not only include Busan and Incheon but also Tokyo and U.S. military installations in Japan.)

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In addition to massive firepower, the KPA would deploy over 100,000 of its crack Special Operations Forces (SOF) through hidden tunnels, submarines, and aircraft. The SOF’s primary task would be to spread confusion (perhaps by wearing ROK military uniforms), destroy military infrastructure including command and control facilities, and delay the arrival of ROK/U.S. reinforcements at the frontline by ambushing troop convoys. DPRK commandos would presumably also try to assassinate South Korean civilian and military leaders and could spread biological weapons such as anthrax.

The war would also quickly move to the sea, where submarines of the Korean People’s Navy (KPN) could target South Korean shipping as well as ROK and U.S. naval vessels. The KPN would also deploy its more advanced submarines, possibly armed with nuclear-tipped ballistic missiles to retain a second strike capability should the conflict reach a nuclear dimension or to compensate for the DPRK’s conventional losses and in case the invasion of the South turns into a military quagmire for the KPA. While North Korea’s air force consists of around 800 obsolete combat aircraft, a number of warplanes could still succeed in bombing civilian and military infrastructure in the South, although ROK air defenses would quickly destroy them.

Whether North Korea would succeed in capturing Seoul remains doubtful. From a conventional military perspective, the last decade has seen a decisive shift in favor of the ROK and the United States. It is also far from clear why Kim Jong-un would order such an assault, which would expose a large part of his military (not to mention North Korea’s civilian population) to destruction. The only plausible reason would be that the dictator becomes convinced the United States is on the verge of launching a military campaign against the DPRK. Another explanation related to this is that the North Korean regime sees its nuclear capabilities as the ultimate guarantor of its survival and would be willing to sacrifice a large portion of its conventional strength to preserve its nuclear weapons arsenal, which almost certainly would be the target of U.S. precision strikes in the event of war. Also, North Korea’s military strategy remains focused on reunifying the Korean Peninsula within 30 days of the onset of hostilities, according to open source intelligence.

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While North Korea’s true military potential is disputable, most analysts believe that tens of thousands of soldiers and civilians would be killed within the first 48 hours of the conflict at a minimum. The corridors where North Korean troops would be advancing would almost certainly be turned into human abattoirs. One military estimate puts the number of North Korean casualties at 100,000 in the first 72 hours. Should only ten percent of the North Korean invading force make it into Seoul, it still could take weeks of urban combat to dislodge them and kill thousands of civilians caught in crossfire, not to mention the thousands of soldiers that will perish in the slow re-conquest of portions of the city.

Yet mass casualties would not only be confined to the South in the event of war. Seoul’s so-called Korean Massive Punishment and Retaliation plan foresees the targeted destruction of sections of Pyongyang in the event of conflict even if it does not cross the nuclear threshold, which could cost the lives of tens of thousands in the North Korean capital. The plan also calls for surgical strikes against key leadership figures of the communist regime as well as military infrastructure. The U.S.-ROK war plan for conflict on the Korean Peninsula purportedly calls for immediate but proportionate retaliation in kind should the North decide to launch an attack. (While fragments of this plan have been leaked to the press, it is impossible to confirm their veracity.)

The bottom line is, should the KPA commit to a large-scale invasion, it would result in the destruction of DPRK conventional military power and the death of several hundred thousand KPA soldiers, not only in the South but also in the North Korean heartland. ROK and U.S. military would prevail in the long run. In the past, such dire odds have not deterred dictators from engaging in reckless military gambles. It is also highly unlikely to deter the North Korean leadership should it perceive that the survival of its regime is at stake.