Essay International

A New Conflict Era
The Growing Tensions between Japan and the Korean Peninsula

by Floriano Filho , 13 July 2020

Japan and the Korean peninsula share a troubled history, and the already tense relationships of these areas have been deteriorating over the past few years. Floriano Filho maps out these tensions as well as their symptoms—which include an arms race—while bringing light to their historical roots.

A widespread armed conflict, possibly nuclear, haunts the Korean Peninsula. In the case of Japan, relations with that region, a former Japanese colony between 1910 and 1945, have a troubled and controversial history that continues today. As for South Korea, the relationship with Japan has already had its ups and downs during the past six decades; while for North Korea the situation has been even more alarming, after several launches of North Korean missiles that have crossed the Japanese airspace, falling within the Sea of Japan. In 2017 alone, North Korea conducted 24 missile launches plus one nuclear test. Two of the launches passed over Hokkaido. Following an idle 2018, the tests continued in 2019 despite several attempts at pacification with the participation of the governments of South Korea and the United States. In March 2020, nine projectiles, mostly short-range ones, were fired over four separate events. New reports were released in April of a barrage of North Korean Kumsong-3 cruise missiles being fired on the eve of 108th birthday of Kim Il-sung, grandfather of current leader Kim Jong-un, and of South Korea’s parliamentary elections.

According to the Joint Chiefs of Staff (JCS), during more than 40 minutes, the surface-to-ship cruise missiles were fired from the coastal town of Munchon, flew around 150 kilometers, and splashed into waters off the North Korean east coast. As if that was not enough, a detailed online report released last May by the Washington DC-based Center for Strategic and International Studies (CSIS) shows a series of satellite pictures of what is claimed to be the modernization and expansion of an intercontinental ballistic missile facility capable of accommodating Pyongyang’s entire ballistic missile arsenal.

The North Korean Nuclear Program

Since the early 1960s, the North Korean government has been investing in a program for the production of nuclear energy. The Yongbiong Nuclear Research Center, for example, was built in 1963 with the cooperation of Russian engineers. But it was only in 2006 that North Korea carried out its first nuclear bomb test. The plutonium used in the artifact had been enriched at the Yongbiong Center itself and the underground detonation occurred in tunnels excavated in the northeast of the country, in a mountainous region called Punggye-ri. After that first North Korean test, another five have been performed so far. According to the Arms Control Association, North Korea has 30 nuclear warheads. By comparison, Russia has 6,490, the United States, 6,185, and China, 290.

Figure 1 Nuclear tests carried out by North Korea
Source: Center for Strategic International Studies (CSIS) Missile Defense Project. Reproduction permitted upon citation of the source.

In addition to nuclear artifacts, a major regional concern is medium and long-range missiles, especially intercontinental ones, which can also carry nuclear warheads. North Korea started launching military missiles in 1984. They had a short-range and were a variation of scuds, a generic name for a series of ballistic missiles developed by the Soviet Union during the Cold War. In that year, under President Kim Il-Sung’s government, seven short-range ballistic missiles were launched, that is, reaching a distance of 150 to 1000 kilometers. Between 1990 and 1994, the year that Kim died of a heart attack at the age of 82, ten more launches were made, including short- and medium-range missiles.

Figure 2. Missile launches and nuclear tests carried out by North Korea
Source: CSIS Missile Defense Project.

The arrival of Kim Jong-un in power in 2011 saw fresh nuclear launches. Tests increased even more, both in quantity and in explosive power. 95 missiles were launched until 2017, the year that broke the record in the number of tests, including the Taepodong-2, which can reach a distance of up to 15,000 kilometers, and the Hwasong-15, with a range of up to 13,000 kilometers. Successive attempts at negotiation by the United States government, which still remains today as one of the pillars of military security in the region, resulted in the historic 2018 meeting in Singapore between President Donald Trump and Kim Jong-un. It was the first time in history that the leaders of the two countries met in person.

Figure 3. Range of North Korean missiles
Source: CSIS Missile Defense Project.

The CSIS is one of the institutions that have been researching the geopolitical situation involving North Korea. It has created a specific program for that purpose. “Beyond Parallel” investigates strategic issues concerning the Korean reunification, such as economic development, migration, food security, human rights, and health. One of the tools used in these studies and investigations are satellite images also produced by the European Space Agency. Through these images it was possible, for example, to identify the Sino-ri base (신오리), 212 kilometers north of the demilitarized zone, equipped with medium-range Nodong-1 ballistic missiles. According to the CSIS experts, it is one of the 20 undeclared operational bases with international agencies and may have been used in the development of the new Pukkuksong-2 (KN-15) missile, revealed only in 2017.

Failure to declare this type of base would make a denuclearization agreement with the United States government unfeasible because it requires the verification and dismantling of nuclear artifacts and their military installations. For researchers Victor Cha and Marie DuMond who coordinate the Beyond Parallel project, the Sino-ri base is part of the North Korean military strategy to achieve nuclear or conventional strike capability particularly against targets in South Korea and Japan. The base was also claimed to serve as a training center for the Strategic Force of the People’s Army of Korea (KPA). To accomplish this, two nearby facilities would be used: the Sobaek-su academy and the Myodu-san training area.

Figure 4. North Korea’s missile launches and nuclear tests
Source: CSIS Beyond Parallel Project. Image generously provided for reproduction in this article by the CSIS team in Washington DC.

The Arms Race in the Region

After the experience with the launch of Scud missiles in Iraq during the 1991 Gulf War, US military technology corporations began to develop a new anti-aircraft apparatus. Private companies were financed by the United States Army’s Missile Defense Agency and developed a high-altitude air defense system, better known by the English acronym THAAD (Terminal High Altitude Area Defense). The main corporation hired to design, build, and integrate the system was Lockheed Martin Missiles and Fire Control, with headquarters in Texas and major factories in Florida and other locations in the United States. Among the subcontractors for the development of technology-based on kinetic energy are large groups such as Raytheon, Boeing, Honeywell, and BAE Systems. The apparatus, including interceptor rockets, radar sensors, truck-mounted launchers, and command and control elements, was initially planned for deployment in 2012. But the rapid increase in tensions in the Asia-Pacific region caused the Pentagon to push ahead of schedule.

Fearing a North Korean attack on Hawaii, the United States deployed a THAAD system in the archipelago in 2009. Subsequently, the apparatus was installed on the island of Guam, in the United Arab Emirates, in Israel, in Turkey, and in Romania. Even before the system’s first two batteries started operating in South Korea in April 2017, there was a reaction from China. Xi Jinping’s government protested, claiming that the system’s radar could be used to spy on the Chinese missile program, posing a threat to the country’s national security. Unofficial restrictions on bilateral trade between South Korea and China were imposed immediately. In addition to the reduction in Chinese tourists visiting South Korea, the frequency of Chinese customers in Korean restaurants in Beijing dramatically decreased. There was also a boycott by the Chinese of the various products of the Korean Lotte conglomerate. Sales in China of vehicles manufactured by Hyundai and Kia Motors plunged drastically.

That was a setback in the constructive bilateral relationship, considering that China and South Korea had resumed diplomatic relations in 1992, breaking the almost total dependence Seoul previously had on the United States. In December 2015 the former two countries signed a bilateral free trade agreement, ending tariffs on almost 90% of goods traded between them. China is South Korea’s main trading partner, which in turn is China’s fourth-largest partner. The annual flow of trade between the two countries exceeds 280 billion dollars. The damage caused to the South Korean economy was only reversed after President Moon Jae-in committed himself to the so-called “three nos”: no other anti-missile systems would be installed in the country, South Korea would not join any regional bloc using the American technology and, finally, there would be no military alliance involving South Korea, the United States, and Japan.

If South Korea was able to rebalance its relations with China relatively quickly, the same cannot be said for North Korea. There have already been five inter-Korean summits trying to end the conflict in the Peninsula, three of them in 2018. In April of that year, Presidents Kim Jong-un and Moon Jae-in signed the Panmunjom Declaration for Peace, Prosperity, and Unification. The document included a commitment to denuclearization, which also depends on negotiations with the United States, in addition to disarmament on the peninsula. But the North Korean government has not shown itself willing to allow inspection or verification of the dismantling of the military arsenal as the American negotiators wanted.

Skepticism about this situation is compounded by the ups and downs of diplomatic-political relations, within and outside the peninsula. The U.S.-led sanctions are considered a major hindrance for North Korean economic development. Since the second summit between Kim and Trump in Vietnam in early 2019 broke down, inter-Korean relations have been even more strenuous. Pyongyang was dissatisfied with the sanctions relief it obtained in return for dismantling its main nuclear complex, considered equivalent to a limited denuclearization measure. The backlash from the failed agreement was renewed threats of nuclear arsenal expansion and the introduction of new strategic weaponry. Hence, regional pacification seems distant, especially when the North Korean government continues to fire missiles into the Sea of Japan, as was the case with two more launched on July 25, 2019. The two projectiles were launched from the city of Wonsan and hit a distance of almost 690 kilometers just when the US National Security Advisor at the time, John Bolton, a staunch critic of regimes like Kim’s, was visiting South Korea. It was the first test since President Donald Trump was in the Korean demilitarized zone at the end of June, becoming the first President of the United States to take a few steps inside North Korea. On July 30, new North Korean short-range missiles were launched from the Wonsan area, on the southeast coast of the country.

Although there were no nuclear explosives originally developed by South Korea itself inside the country, in 2004 that scientists linked to the South Korean government secretly enriched uranium to levels close to those used in nuclear bombs. Years after the end of the war on the peninsula, the United States stored nuclear weapons in South Korean territory. From 1958 to 1991, at the height of the Cold War, the US government kept a nuclear arsenal in the country that reached a maximum number of approximately 950 warheads in 1967. The absence of nuclear weapons on South Korean soil and the continuing regional instability drove South Korea’s missile program. The country has projectiles that can reach up to 1,500 kilometers away. In other words, they would be able to reach any point on the main islands of Japan in the event of an unlikely military conflict between the two nations.

Japan, in its turn, despite the limitations imposed by article 9 of its Constitution, [1] has six destroyers equipped with the Aegis system in service and is manufacturing two more. The Aegis Ballistic Missile Defense System (ABMD) is a program coordinated by the United States Department of Defense’s Missile Defense Agency. It is used to protect against short to medium-range ballistic missiles. A single Aegis Ashore system can cover a much larger geographic area than a THAAD system, which is often used to protect geographically smaller areas such as the ones covered by South Korea or Turkey.

In September 2018, one of these ships, JS Atago, managed to shoot down another ballistic missile during a test in Hawaii. The first test similar to this, conducted by Japan’s defense forces aboard a ship, took place in 2007. In April 2019, the US State Department authorized Japan’s purchase of the largest batch of defense missiles ever acquired by the country. The potential sale was announced by the Defense and Security Cooperation Agency, linked to the Pentagon, and includes 56 SM-3 Block IB model missiles, with an estimated cost of U$1.15 billion. Raytheon and Mitsubishi Heavy Industries are jointly developing a new generation of defense missiles.

Figure 5. South Korea’s ballistic and cruise missiles
Source: CSIS Missile Defense Project.

The Deterioration of Relations Between Japan and South Korea

It was not necessary to fire a single South Korean missile to sour diplomatic relations with Japan, which were normalized only in 1965. There is still resentment over the period of Japanese colonization, despite South Korea currently being Japan’s third-largest trading partner and vice versa. Although at the end of 2008, the South Korean trade deficit with Japan exceeded U$24 billion.

At least two issues in the context of the colonial period, but particularly during the Second World War, still cause great discomfort and tension between the two countries: Korean women forced to work in Japanese military brothels and forced labor by Koreans in Japanese factories. About 150,000 Koreans were forced to work in industries and mines in Japan during the war. In addition, there is a dispute over the sovereignty of the islands called Takeshima, in Japanese, and Dokdo, in Korean, and also the narrative that Koreans consider distorted in some Japanese history textbooks. These issues in particular have always contaminated the relations of the two countries since the diplomatic resumption, with moments of greater or lesser tension. In 2012, for example, there were protests from the Japanese government when a South Korean president, Lee Myun-bak, [2] first visited the islands. In July 2019 South Korea made an official complaint after a Tokyo 2020 Olympic Torch Pass map included the islands as part of Japanese territory.

More recently, a series of new episodes appear to be further disrupting the coexistence between the two countries. In November 2018, South Korea announced a plan to close a foundation created three years earlier and funded by Japan to compensate Koreans forced to work in military brothels during World War II. The South Korean decision was criticized by the Japanese government for preventing the settlement of a dispute that has been going on for decades between the two countries. Before that, Japan had decided not to participate in a military maritime event after the South Korean government requested that the Japanese navy not fly the imperial flag (“Rising Sun”) on a combat ship.

In December 2018, the Japanese government accused a South Korean Navy destroyer of aiming a radar normally used as a warning before an attack on a Japanese military surveillance aircraft. Japan’s Defense Minister Takeshi Iwaya described the South Korean action as “extremely dangerous” and warned that it could “cause an unexpected situation.” The South Koreans claimed they were only performing standard tests with the equipment, with no intention of threatening the Japanese aircraft. Shortly before that event, in October 2018, disagreements surfaced when South Korea’s Supreme Court condemned Nippon Steel for the use of Korean forced labor during the colonial period. Each of the four claimants was awarded compensation equivalent to approximately U$100,000. In the following month, the same court made a similar decision in relation to five other plaintiffs against Mitsubishi Heavy Industries. The outcome of these judgments opened the possibility that more than a thousand new claimants would also enter against several Japanese companies, starting a trend that could create a wave of compensatory actions.

The Japanese government was dissatisfied with the decisions, arguing that all financial issues, including reparations for the colonial period, had been resolved in 1965 by the diplomatic resumption treaty between the two countries. According to a secret CIA report on the future of the Japan-Korea relationship declassified in 2006, financial and property issues were the most difficult in the 14 years of negotiations. In the end, it was agreed that “all problems relating to the properties, rights, and interests of the two signatories and their populations... have been completely and definitively resolved”. Under the terms of the agreement, Japan made donations in goods and services equivalent to U$300 million and loans with interest below the international market value equivalent to U$200 million. The equivalent of U$300 million in private credits was also offered, in addition to the return of art and historical pieces taken from Korea during the colonial period. Nippon Steel and Nachi-Fujikoshi assets in South Korea were frozen to guarantee compensation payments provided for in the lawsuits. The escalating tensions have prompted the Japanese government to tighten control over exports to South Korea of three chemicals essential to the global semiconductor chain.

Those chemical substances included fluoropolymers, used in cell phone displays; photoresistors used to transfer electrical patterns in silicon semiconductor wafers; and hydrogen fluoride, used as a gas in the manufacture of microchips. The three chemicals are considered sensitive because they can have dual uses, both for civilian and military purposes, which makes their circulation more controlled by the Wassenaar agreement. According to a complaint made by the Japanese broadcaster NHK, some of these chemicals, especially hydrogen fluoride, are being passed on to third countries, including North Korea, increasing the risk of their use in chemical weapons. The South Korean government denied the transfer and the World Trade Organization agreed to analyze the case. It is not the first time that the WTO has the need to engage in a trade dispute between the two countries. In 2013 South Korea banned Japanese fish imports, claiming they could have been contaminated after the Fukushima radioactive spill two years earlier. At the time, Japan complained that the measure was a retaliatory commercial tactic. The Japanese decision was particularly hurtful for South Korea because the semiconductor production chain became its main industrial and export sector. According to the Organization for Economic Cooperation and Development (OECD), semiconductors accounted for more than 17% of South Korean exports in 2017. Korean microchips, for example, have an important share in the global electronics chain, with the two largest global manufacturers: Samsung Electronics and SK Hynix. In addition to the greater control of exports of these chemicals, in August 2019 the Japanese Cabinet removed South Korea from a 27 country list that has preferential access to Japanese exports covering more than 1,000 items.

The Politicization of the Crisis Between Japan and South Korea

The exaggerated growth of the crisis between South Korea and Japan provoked uncontrolled reactions. In July 2019 a 78-year-old South Korean protester died after setting himself on fire in front of the Japanese embassy in Seoul, protesting the political-commercial dispute between the two countries. According to the local press, his father-in-law had been one of those forced to work in Japanese industries during the colonial period. There was a decline in the number of tourists not only due to the deterioration of relations but also due to the slowdown in the Korean economy. Low-cost operator T’way Air Co, for example, decided to cancel in mid-September 2018 five routes linking South Korea to Saga, Kumamoto, and Oita. Flight suspensions began in late May, via the Saga-Daegu route. As there were also cities in South Korea that canceled exchange programs with Japanese prefectures, other South Korean airlines also started to cancel flights to Japan. Boycotts of Japanese products also started to spread through Korean stores and supermarkets, ranging from beers to Japanese clothing brands. A new online community, “NoNo Japan”, was created to inform about which products to boycott.

In the South Korean National (and unicameral) Assembly, where the center-left Democratic Party (Minjoo) holds the majority of seats, a “Special Commission on Japanese Economic Aggression” was created. The commission’s chairman, Choi Jae-sung, told foreign reporters that he would ask President Moon Jae-in to denounce Japan to the United Nations Security Council. At least temporarily, President Moon, a lawyer who has acted in human rights cases, has been a political beneficiary of disagreements, as public support for an “external adversary” constrains party opposition. For the associate professor of political science and international studies at Hanyang University, Joseph E. Yi, “the left in Korea is very anti-Japanese and has a post-colonial vision, seeing China and Korea as opponents of Japanese colonialism”. [3] This would explain President Moon Jae-in’s ideological position.

That confrontational spiral seems far from over and almost got a lot worse in 2019, when South Korea decided not to renew the General Agreement on Security of Military Information (GSOMIA). Signed in November 2016, it allows for the exchange of sensitive information between the military intelligence agencies of the two Asian countries on North Korea. Japanese Foreign Minister Taro Kono was hopeful that Seoul would reconsider its decision, but only after US pressure, Moon Jae-in’s government announced a dramatic last-minute reversal decision, just hours before the expected expiry of the deal. The unexpected South Korean move provided some breathing air to an increasingly damaged relationship with Japan in the paramount realm of national security. After all, trade and defense sectors have largely contributed to a minimum of regional stability over decades, particularly during times of troubled political environment. On the other hand, that kind of cooperation has been yet another factor for wearing out the inter-Korean relationship. A recent explosive symbol of that was the blow-up by North Korea of its joint liaison office with South Korea in June 2020. The blast destroyed not only the building established in 2018 in the Kaesong Industrial Zone, just north of the Demilitarized Zone. It also indicated harder times for the region and elsewhere should not go away anytime soon, unless the US and the UN decide to start reversing at least some of the economic sanctions imposed on North Korea.

Dossier's Articles

by Floriano Filho, 13 July 2020

Further reading

“Japan-South Korea Spat Takes Dangerous Turn as Trump Stays Quiet”, in Bloomberg News, 2019 Retrieved July 6, 2019.
• Beckley, M., Horiuchi, Y., & Miller, J. M., “America’s Role in the Making of Japan’s Economic Miracle.” in Journal of East Asian Studies, 1(21), 2018.
• Bosak, M. M., “Understanding the peaks and valleys of Japan-South Korea ties.” in The Japan Times, 2019, May 16.
• Central Intelligence Agency., “The Future of Korean-Japanese Relations.” Langley, Virginia, 1966.
• Ence, J. J., “Explaining Conflicts in Japanese-South Korean Relations”. Utah State University, Logan, Utah, 2013.
• Farley, R., “Japanese Tech Export Controls on South Korea?”, in The Diplomat, 2019.
• Gentile, G., Vonne, Y., Cr Ane, K., Madden, D., Bonds, T. M., Bennet, B. W., Scobell, A., Four Problems on the Korean Peninsula: North Korea’s expanding nuclear capabilities drive a complex set of problems, Los Angeles, California, 2019.
“Nuclear Weapons Program—North Korea”, in, 2019, Retrieved July 13, 2019
THAAD on the Korean Peninsula, Institute for Security and Development Policy, Stockholm, 2017
• Kan, K., “Explaining South Korea’s Sharp Shift in 2018 toward Japan.”, The Asan Forum, 7(4), 2019, 1–18.
• Lee, J.-Y., & Oba, M., “Japan-Korea Relations: Hitting an All-Time Low.”, in Comparative Connections, 21(1), 2019, 105–114.
• Miller, J. B., “Japan and South Korea’s History Wars Are About to Get Ugly.”, in Foreign Policy, 5–8, 2019
• Nishino, J., Japan’s Security Relationship with the Republic of Korea. Opportunities and Challenges, Washington DC, 2015
• Pan, E., South Korea’s Ties with China, Japan, and the U.S.: Defining a New Role in a Dangerous Neighborhood, New York, 2006
• Suh, J. J., “Missile Defense and the Security Dilemma: THAAD, Japan’s “Proactive Peace,” and the Arms Race in Northeast Asia.”, in The Asia-Pacific Journal | Japan Focus, 15(5), 2017
• Tatsumi, Y., “Fallout from Japan-South Korea tensions.”, in The Japan Times, 2019, January 31.
• Volodzko, D. J., “China wins its war against South Korea’s US THAAD missile shield—without firing a shot.”, in South China Morning Post, 2017,
• Wolman, A., “Japan-Korea Relations Could Get Worse Before They Get Better.”, 2019, Retrieved July 27, 2019
• Yeo, M., US clears Japan for $1.2B missile package to defend against ballistic threats.”, 2019, Retrieved July 29, 2019

To quote this article :

Floriano Filho, « A New Conflict Era . The Growing Tensions between Japan and the Korean Peninsula », Books and Ideas , 13 July 2020. ISSN : 2105-3030. URL :

Nota Bene:

If you want to discuss this essay further, you can send a proposal to the editorial team (redaction at We will get back to you as soon as possible.


[1As the Japanese Constitution forbids the maintenance of an army, navy or air force, and the engagement in battles for settling international disputes, Self Defence Forces were established in 1954.

[2The former mayor of Seoul and former president of South Korea between 2008 and 2013, Lee was sentenced in 2018 to 15 years in prison for corruption.

[3Joseph E. Yi, quoted in

Our partners

© - Any replication forbidden without the explicit consent of the editors. - Mentions légales - webdesign : Abel Poucet