What to expect from Japan-South Korea relations after Kishida

To be continued? On Friday, Japanese Prime Minister Fumio Kishida met with his South Korean counterpart, President Yoon Suk Yeol, in Seoul. “There is a lot of history . . . but it is very important to inherit the efforts of our predecessors who overcame difficult times, and cooperate toward the future,” Kishida told Yoon. It marked the twelve and likely final time the two will meet as leaders, as Kishida has said he will step down at the end of September. Under Kishida and Yoon, Japan-South Korea relations have experienced a renaissance, with both leaders staking their political standing on overcoming deep-rooted friction between their nations. Among the two leaders’ accomplishments, a trilateral summit with US President Joe Biden in August 2023 at Camp David marked a “historic” breakthrough.

But will these efforts move forward after Kishida exits? Or will they be left to history? Below, Atlantic Council experts answer four pressing questions about the Japan-South Korea relationship.

1. How has the Japan-South Korea relationship changed under Kishida and Yoon?

The Kishida-Yoon duo has been pivotal. The restoration and developments in Japan-South Korea relations have been vital in dealing with the ever-growing security threats and challenges in the Indo-Pacific. For decades, the leaders of the two countries have vowed “future-oriented” ties that often ended with little progress in cooperation while feuding over historical and sovereignty disputes. Moreover, Japan-South Korea relations hit a new low during the administration of South Korean President Moon Jae-in, with a series of contentious issues, such as the radar lock-on incidentunilateral reversal of the comfort women agreement, court rulings over Korean laborers during the colonial era, and the removal of South Korea from Japan’s trade “whitelist.”

Kishida and Yoon, however, have defied this trend by following through on their promises to bridge strategic perspectives, maintain regular communication, and deepen security ties, all while minimizing the negative effects of their disputes. In particular, both Japan and South Korea have worked Closely with the United States to deepen and institutionalize the trilateral security partnership within their capacity to deal with the myriad threats and concerns in the Indo-Pacific. This was epitomized in the Camp David Summit of August 2023.

While there are concerns over the sustainability of the initiatives by Kishida and Yoon, as well as various political and technical issues in security cooperation, there is no doubt that the two leaders opened a new chapter in Japan-South Korea relations and proved that the two countries can work together as partners.

—Ryo Hinata-Yamaguchi is a nonresident senior fellow in the Scowcroft Center’s Indo-Pacific Security Initiative, a project assistant professor at the University of Tokyo, and an adjunct senior fellow at the Pacific Forum.

South Korea-Japan relations under Yoon and Kishida centered on the restoration and revitalization of the two countries’ ties. Driven by the two leaders and their aides’ personal engagement and a mutual understanding of the changing geopolitical environment, Yoon and Kishida sought to quickly normalize and bolster security cooperation, including trilateral security arrangements with the United States. From settling the 2018 South Korea-Japan radar lock-on dispute and resuming bilateral military information sharing restoring each other to their respective trade whitelists, Yoon and Kishida’s eleven earlier rounds of talks accumulated into several milestones. Together, Yoon and Kishida ended the twelve-year diplomatic cold spell that had befallen South Korea-Japan relations.

—Bee Yun Jo is a nonresident senior fellow in the Indo-Pacific Security Initiative and an associate research fellow in the Defense Strategy Division at the Center for Security and Strategy at the Korea Institute for Defense Analyses.

2. Will Japan’s approach to foreign policy and to South Korea change after Kishida leaves?

While much depends on who takes charge, the next administration is likely to maintain the core aspects of Japan’s foreign policy and security strategy, much like previous administrations. As for relations with South Korea, however, it is less clear whether there will be continuity. While the broad agenda of keeping cooperative relations under the scope of the Japan-South Korea-US trilateral partnership is unlikely to change, the next administration may be less flexible and patient with Seoul over historical and sovereignty issues—particularly if a more conservative Japanese prime minister takes over. Such a stance could be more explicit, particularly if politicians gain greater influence in South Korea, and more so if they take power in the next South Korean administration.

—Ryo Hinata-Yamaguchi

3. Will Yoon seek a similar approach with the next Japanese prime minister?

Expect more continuity than change. Although there is continued discontent among opposition parties, which are pressuring the Yoon administration to take a stronger stance against Japan, Yoon’s emphasis on South Korea-Japan relations is unwavering. As South Korea and Japan await the sixtieth anniversary of their diplomatic relations in 2025, the Yoon administration is deliberating on new and future-oriented measures to deepen their bilateral ties. This could possibly take the form of developing a new South Korea-Japan Joint Declaration or more practical agreements, such as a preclearance system at airports to enable speedy entry and departure between the two countries.

Improving South Korea-Japan relations will continue to be critical to Seoul as Yoon’s foreign policy accomplishments also rest on reinvigorating and expanding South Korea-US-Japan trilateral security cooperation. With the backdrop of Pyongyang and Moscow’s worrisome ties, and as a means of weathering out uncertainties with the upcoming US election, trilateral security cooperation is vital. In implementation of Yoon’s “global state pivotal” vision, trilateral cooperation is critical to expanding Seoul’s relations horizontally and vertically with other likeminded countries, including Australia. And as the past few years have demonstrated, a sound South Korea-Japan relationship is the key precondition and variable to all these efforts.

Challenges remain, however. Opposition voices are adamant on the latest incidents—from the Line messaging app to historical grievances over the Sado Gold MineThere are concerns that if the next prime minister in Japan visits the Yasukuni Shrine—a controversial monument honoring Japan’s war dead—then Yoon’s freedom to maneuver on South Korea-Japan relations may be constrained by domestic backlash. No incumbent prime minister of Japan has visited Yasukuni since Prime Minister Shinzo Abe’s visit in 2013, although Japanese cabinet members have frequently visited the site. The latest such visit was on August 15by three cabinet ministers, while Kishida sent a ritual offering.

—Bee Yun Jo

4. What should the United States do to ensure Japan and South Korea continue strengthening relations?

Kishida and Yoon both entered office aiming to improve Japan-South Korea ties, and they have been immensely successful. At the same time, the United States has been instrumental in supporting and supplementing their efforts. In August 2023, US President Joe Biden invited the two leaders to the historic retreat at Camp David—a location known for hosting the most influential global leaders at key points in history. Biden declared it a “new chapter” for the countries. Since then, there have been several bilateral summits between Kishida and Yoon, including one in Seoul and one in Washington, D.C..

Why has the Biden administration pushed so hard for this improvement in Japan-South Korea relations? China is one big reason. Beijing has consistently increased its maritime aggressions in the Indo-Pacific and constantly dangles the threat of economic coercion. Furthermore, Beijing has been surreptitiously aiding the Russian war effort, its demonstrating disregard for the rules-based international order. North Korea is another reason. Pyongyang has continued to develop its conventional and nuclear capabilities and declared South Korea its “principal enemy,” while also deepening ties with Russia and providing missiles to Moscow for its war against Ukraine.

But apart from China and North Korea, there are also important opportunities for the three countries to strengthen the rules-based international order and bolster economic prosperity. This is why the Camp David summit and meetings since then have focused so much on building cooperation in the Indo-Pacific with the Association of Southeast Asian Nations and the Pacific Island countries, building safety around cybersecurity and artificial intelligence, combating climate change, and more.

None of these reasons for enhanced trilateral cooperation will disappear once Kishida leaves office. It continues to benefit the United States if Japan and South Korea improve their relations, both bilaterally and with Washington. To see this happen, the United States should work to formalize annual meetings, such as the Trilateral United States-Japan-Republic of Korea Indo-Pacific Dialogue, and other such meetings below the presidential level to keep momentum. Further, people-to-people exchanges in the form of exchange programs, bilaterally and multilaterally, should continue to be prioritized to create a common understanding from the bottom up.

—Lauren D. Gilbert is a deputy director with the Atlantic Council’s Indo-Pacific Security Initiative.