Key Drivers Behind South Korea and Japan's Rapprochement

 

Although South Korea and Japan have been close allies of the United States and established diplomatic relations in 1965, their political, diplomatic, and defense cooperation has been hindered by historical grievances, particularly regarding the issue of forced labor during Japan's colonial rule of Korea from 1910 to 1945. While the two nations have had significant economic cooperation, their political and security relations have been strained for decades. South Korea has consistently pushed for Japan to compensate victims of wartime forced labor, a demand Japan has refused, citing prior compensation agreements. However, since 2022, in light of increasing security threats posed by North Korea and China as well as pushes from the United States, the Yoon administration has made significant efforts to overcome these historical barriers. These efforts led to improved bilateral ties with Japan and the landmark trilateral summit in 2023, where the United States, Japan, and South Korea pledged to strengthen their collaboration on regional security challenges.

1. Key Historical Issues Hindering Political and Diplomatic Cooperation Between South Korea and Japan

South Korea and Japan established diplomatic relations in 1965; however, their relations have been marred by several historical disputes that have negatively affected the development of their political, economic, and diplomatic ties. The major historical issues between the two countries include: (i) the territorial dispute over Dokdo/Takeshima Islands; (ii) visits by Japanese politicians to the Yasukuni Shrine; (iii) the "comfort women" issue; and (iv) the issue of forced labor. Among these disputes, the issue of forced labor is considered the most significant, frequently causing tensions and protests within South Korea and putting pressure on South Korean leaders to address the matter in their diplomatic relations with Japan.

 

During Japan's colonization of Korea from 1910 to 1945, Japan enacted the National Mobilization Act, forcibly recruiting approximately 280,000 to 1.2 million Korean colonial laborers to work in factories and mines supporting Japan's military-industrial strategy and territorial expansion both at sea and on land. In 1997, 15 South Korean forced labor victims filed a lawsuit against Japan’s Nippon Steel Corporation over their forced recruitment, but the Japanese courts dismissed the case. In 2012, the South Korean Supreme Court took up the case, and in 2018, it issued a ruling requiring two Japanese companies, Nippon Steel and Mitsubishi Heavy Industries, to each pay compensation of $77,000 per victim to the 15 individuals identified as victims of forced labor. However, the Japanese government did not accept the South Korean court's ruling on compensation and refused to pay any reparations. As a result, relations between South Korea and Japan reached their lowest point, with tensions evident in various areas, such as: (i) South Korea suspending cooperation on military intelligence sharing with Japan regarding North Korea; (ii) Japan imposing restrictions on the export of semiconductor materials to South Korea; (iii) South Korea removing Japan from its list of preferential trade partners; (iv) South Korean citizens boycotting Japanese goods.

 

 

The key factors motivating recent adjustments in cooperative relations between South Korea and Japan focus on shared concerns about regional and global strategic security issues, including:

- North Korea's nuclear and missile developments: Both Japan and South Korea are deeply concerned about North Korea's rapid progress in nuclear development and its frequent missile tests in recent years. These activities pose a direct threat to the security of both nations.

- Regional tensions and coercive actions: Both countries are alarmed by actions aimed at changing the status quo, including coercive activities and threats to use force in the Indo-Pacific region, especially in the South China Sea, the East China Sea, and the Taiwan Strait. Russia’s military invasion of Ukraine has further heightened concerns in both nations about the potential for similar precedents in Northeast Asia.

- China’s military growth and ambitions: Japan and South Korea share apprehensions about China's increasing military strength and ambitious goals, which contribute to intensifying U.S.-China competition across all areas, including politics, security, economy, military, and technology. As a result, both nations see a pressing need to align themselves with allies to ensure their security and development.

- U.S. influence and trilateral cooperation: As two of the United States’ closest and most significant allies in Asia, South Korea and Japan recognize the critical role of the U.S. in encouraging reconciliation and fostering cooperation between them. Such cooperation is essential for the U.S. to advance its trilateral alliance with Japan and South Korea, enabling the implementation of its security and foreign policies in the region.

 

Among the aforementioned factors, the most pressing concern for both South Korea and Japan is security, particularly the threats posed by North Korea's rapid advancements in nuclear weapons and missile testing. Since early 2022, North Korea has conducted over 100 missile tests, including intercontinental ballistic missiles (ICBMs) capable of traveling thousands of kilometers. North Korea has also claimed its first "successful" test of a reconnaissance satellite missile and has tested underwater drones capable of carrying nuclear weapons.

 

South Korea and North Korea are products of Cold War-era division, and the two nations remain technically at war, having only signed an armistice in 1953. Both claim legitimate authority over the entire Korean Peninsula, maintaining a state of military confrontation without true peace. For Japan, the situation is further complicated by historical ties to the Korean Peninsula. As a former regional power that colonized Korea from 1910 to 1945, Japan played a role in the eventual division of the peninsula. Moreover, as a close U.S. ally, Japan has consistently pressured North Korea through sanctions and demands for the dismantling of its missile and nuclear programs. This has led North Korea to view Japan as a hostile adversary, and in the event of regional conflict between the two Koreas, Japan is considered a potential target. In practice, North Korea has repeatedly launched missiles into Japanese waters, underlining its adversarial stance toward Japan. Both South Korea and Japan are keenly aware of the shared security challenges posed by North Korea’s missile and nuclear weapons development. While Japan is not a direct party to the inter-Korean dispute, it must closely monitor security developments on the Korean Peninsula, especially those involving North Korea’s missile and nuclear capabilities. Recognizing that no single country can resolve the security challenges posed by North Korea, both Japan and South Korea acknowledge the need to overcome historical grievances and cooperate. This collaboration, particularly with their mutual ally, the United States, is essential to addressing North Korea’s nuclear issues and ensuring regional stability.

To foster reconciliation and strengthen cooperation in addressing North Korea and other regional security issues, South Korea and Japan have reinitiated several previously stalled efforts in diplomacy, security, and economic collaboration.

 

 

The South Korean government has taken significant steps to resolve the forced labor compensation issue, a major obstacle to bilateral cooperation. On March 6, 2023, South Korean Foreign Minister Park Jin announced that the South Korean government would establish a fund, supported by South Korean companies benefiting from the 1965 wartime compensation agreement with Japan, to compensate 15 forced labor victims who won their case in South Korea's Supreme Court ruling in 2018. This approach avoids demanding direct compensation from Japanese companies. This decision was seen as a goodwill gesture with significant political implications, aimed at unblocking the impasse in bilateral relations caused by the forced labor issue. Resolving this internal compensation issue paved the way for high-level visits between the two countries, restoring diplomatic ties and enabling immediate cooperative agreements.

 

On March 16, 2023, South Korean President Yoon Suk-yeol made an official visit to Japan, marking the first high-level visit in 12 years to restore bilateral relations. During this visit, South Korea and Japan agreed to resume the General Security of Military Information Agreement (GSOMIA), signed in 2016 but suspended by South Korea in 2019 due to diplomatic tensions. The agreement facilitates the exchange of real-time satellite imagery and other intelligence on North Korea's missile and nuclear developments, enabling both nations to implement coordinated countermeasures. Reinstating this agreement reflects a high level of mutual trust and a shared commitment to addressing their common security challenges posed by North Korea. In response to President Yoon's visit to Japan, Japanese Prime Minister Fumio Kishida made a return visit to South Korea in early May 2023. Observers viewed this reciprocal visit as a signal that the two nations had fully normalized diplomatic relations, laying the foundation for strengthened bilateral cooperation and smoother trilateral collaboration with the United States. These high-level visits have been instrumental in rebuilding trust and creating favorable conditions for joint initiatives, not only between South Korea and Japan but also within the broader framework of South Korea-Japan-U.S. collaboration to address regional and global security challenges.

 

 

South Korea has actively participated in bilateral military exercises with its ally, the United States, and resumed participation in several multilateral exercises, including those with Japan, which had been suspended in the past. In just the first half of 2023, South Korea engaged in four significant bilateral and multilateral drills focused on addressing security challenges posed by North Korea: February 22, 2023: South Korea participated in a trilateral ballistic missile defense exercise with the U.S. and Japan in the Gulf of Korea, focusing on identifying and intercepting ballistic missiles. March 15, 2023: South Korea joined a multilateral anti-submarine warfare exercise named "Blue Dragon," involving Japan, the U.S., Canada, and India in South Korean waters. The exercise coincided with North Korea's missile tests. March 29, 2023: South Korea and the U.S. conducted the "Ssang Yong" amphibious landing exercise in South Korean waters, involving over 2,000 U.S. troops to enhance military coordination and deter North Korea. April 3-4, 2023: The navies of South Korea, Japan, and the U.S. held a two-day trilateral anti-submarine exercise in the East China Sea, featuring the U.S. aircraft carrier USS Nimitz.

 

 

South Korea and Japan have also made significant progress in reconciling trade disputes and enhancing economic cooperation: March 16, 2023: Japan's Ministry of Trade announced the easing of export restrictions on three critical materials (fluorinated polyimide, photoresists, and hydrogen fluoride) used in semiconductor production. These restrictions had been imposed on South Korea in 2019. This decision was made during South Korean President Yoon Suk-yeol's high-level visit to Japan. In response, the South Korean government announced on the same day that it would withdraw its complaint against Japan at the WTO over these trade restrictions. April 24, 2023: South Korea's Ministry of Trade, Industry, and Energy announced Japan's reinstatement to South Korea's "white list" of preferred trade partners. This reinstatement simplified export processes for South Korean companies trading strategic goods with Japan, reducing review periods from 15 to 5 days. On June 27, 2023, Japan's Minister of Trade, Yasutoshi Nishimura, announced that Japan would return South Korea to its "white list" of preferred trade partners. This move prioritized streamlined export procedures for high-end Japanese electronic components destined for South Korea. These reconciliatory trade measures highlight the commitment of both nations to restoring economic relations, paving the way for improved ties ahead of the anticipated trilateral summit with the U.S. in August 2023.

 

On financial cooperation, on June 29th, 2023, the Finance Ministers of Japan and South Korea agreed to resume negotiations on a $10 billion currency swap agreement originally signed in 2001 and suspended in 2015 due to diplomatic tensions. Once restored, the agreement will serve as a foundation for broader financial discussions between the two nations, particularly in the context of shared risks stemming from security concerns and geopolitical competition impacting economic and financial stability. Since the beginning of 2023, relations between South Korea and Japan have seen rapid improvements across various areas, including high-level political diplomacy, military cooperation, economic and financial partnerships, and trade. This progress is expected to have a significant impact on the two countries' coordination with their mutual ally, the United States, to address nuclear and missile threats from North Korea. The U.S. has long sought to improve collaboration between its regional allies, South Korea and Japan, but with limited success until now. The changing dynamics of international and regional security in early 2023, particularly the North Korean factor, have successfully driven reconciliation and cooperation between the two allies. This rapprochement is crucial for the U.S., enabling smoother coordination and joint implementation of security policies related to North Korea, as well as other regional initiatives, including the Indo-Pacific Strategy. During a trilateral meeting of National Security Advisors from the U.S., Japan, and South Korea held on June 15, 2023, in Tokyo, U.S. National Security Advisor Jake Sullivan praised the improved South Korea-Japan relations as "historic steps" in bilateral relations.

 

Given the current momentum in security and foreign policy cooperation between South Korea and Japan - particularly within the framework of their alliance with the U.S., there could be further collaboration. The complex security environment in the region, especially North Korea's missile and nuclear developments, is unlikely to abate in the near term. South Korea recognizes the necessity of cooperating with Japan and relying on its U.S. ally for security assurances. The leadership factor in South Korea also plays a key role in maintaining its current security and foreign policy. President Yoon Suk-yeol, known for his pro-U.S. stance and openness to improving relations with Japan, is only two years into his term, which lasts until mid-2027. As such, the continuation and implementation of South Korea's current foreign policy are likely to persist at least until the end of his administration. However, shifts in the country's leadership could lead to changes in its security and foreign policy.

East Sea Institute, Diplomatic Academy of Vietnam
An original version of the article was published here.

 

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