A Historic Turning Point in Japan-South Korea Defense Cooperation: Resumption of Joint Exercises After 9 Years and New Developments in Advanced Technology Cooperation

On January 30, 2026, the Japan-South Korea defense ministerial meeting held in Yokosuka, Kanagawa Prefecture, marked a significant turning point in the security environment of Northeast Asia. Defense Minister Shinjiro Koizumi and South Korean Minister of National Defense An Gyeo-beok agreed to resume maritime search and rescue training for the first time in nine years, and they also reached a consensus on exploring advanced defense technology cooperation in artificial intelligence (AI), unmanned systems, and space. This historic agreement symbolizes that both countries have entered a new phase of jointly addressing the increasingly serious regional security challenges, transcending past historical conflicts.

At the beginning of the meeting, Minister An stated, "We should honestly face the past, evaluate the present, and seize the opportunity to move toward the future," demonstrating a willingness for positive development in bilateral relations. This statement culminated in the concrete outcome of resuming maritime search and rescue training, which had been suspended since 2016. According to the South Korean Ministry of National Defense, the training conducted by the South Korean Navy and the Japan Maritime Self-Defense Force will be humanitarian in nature. The cooperation of naval vessels from both countries in joint training again holds symbolic value that goes beyond mere military significance.

The background to the suspension of training was the tensions that surfaced between the two countries regarding historical recognition and territorial issues from 2016 to 2017. In particular, the issue of the Japan Maritime Self-Defense Force P-1 patrol aircraft being illuminated by fire control radar in December 2018 significantly damaged trust between the defense authorities of both countries. For several years thereafter, Japan-South Korea defense cooperation was effectively halted, and regional security experts expressed concern that the gap between the two countries was not closing.

The situation changed with the Camp David summit on August 18, 2023. South Korean President Yoon Suk-yeol, then-Prime Minister Fumio Kishida, and U.S. President Joe Biden issued a joint statement proclaiming the "spirit of Camp David" and agreed to institutionalize trilateral cooperation. Although this framework is not a legally binding treaty, it became a politically significant document promising cooperation in a wide range of areas, including maritime security, economic security, missile defense, and addressing North Korea's cyber threats.

The recent defense ministerial meeting should be understood in the context of materializing the Camp David agreement. The defense ministers of both countries also agreed to institutionalize annual defense ministerial meetings, establishing regular communication channels. This reduces the risk that temporary political tensions will halt overall defense cooperation. By institutionalizing dialogue between defense authorities, rapid communication and problem-solving will be possible even when issues arise.

Notably, both countries agreed to explore cooperation in advanced defense technology. The three areas of AI, unmanned systems, and space are becoming critically important in modern military operations. Given the rapid enhancement of capabilities in these fields by China and Russia, it is strategically imperative for Japan and South Korea to deepen technological cooperation.

Regarding unmanned systems, the Ukraine war has dramatically demonstrated the tactical importance of small unmanned aerial vehicles (drones). While South Korea leads the world in commercial drone technology, Japan has strengths in precision sensor technology and autonomous control systems. By integrating the technical strengths of both countries, there is potential to develop advanced unmanned systems for reconnaissance, surveillance, and even attack missions.

In the field of AI, a wide range of military applications is anticipated, including decision support, target identification, and cyber defense. By combining Japan's advanced AI research with South Korea's practical implementation capabilities, both countries can build their own defense AI capabilities while reducing dependence on third countries.

The space domain has become essential for communication, positioning, early warning, and information gathering. To detect North Korea's ballistic missile launches early and relay information to interception systems, a space-based sensor network is crucial. Japan established a Space Operations Group within its Ministry of Defense in 2023, and South Korea is also considering the establishment of a Space Force. If both countries cooperate in space situational awareness (SSA) and early warning satellites, regional deterrence will be significantly enhanced.

The defense ministers also agreed that expanding personnel exchanges and unit-level exchanges is essential for building mutual trust. Recent examples of exchanges include interactions between the South Korean Army's 3rd Officer School and the Japan Ground Self-Defense Force's Officer Candidate School, as well as the visit of the South Korean Air Force aerobatic team "Black Eagles" to Naha Air Base in Okinawa Prefecture. The Black Eagles conducted their first exchange with the Japan Air Self-Defense Force's "Blue Impulse," fostering personal relationships between pilots from both countries. Such grassroots-level exchanges function as a buffer during times of heightened political tension.

Interestingly, on the day of the meeting, January 30, a South Korean Air Force C-130H transport aircraft made an emergency landing at Naha Air Base. This incident occurred while en route to an international defense exhibition in Saudi Arabia due to a minor technical issue. Minister An expressed gratitude for the swift support from the Japanese side, stating that this incident embodies the symbolic significance of the meeting. In fact, the response to the aircraft's emergency is a prime example of how crucial cooperation between the two countries' militaries is during peacetime.

The backdrop of this agreement is the deteriorating regional security environment. On January 5, 2026, North Korea launched a hypersonic missile toward the Sea of Japan. Kim Jong-un, General Secretary of the Workers' Party of Korea, emphasized the necessity of nuclear deterrence due to the "recent geopolitical crisis." North Korea's nuclear and missile development has accelerated through 2025 and continues into 2026. For both Japan and South Korea, the threat from North Korea is the most pressing common security challenge.

China's maritime expansion is also a concern for both countries. In his New Year's message on January 1, 2026, Chief of Staff of the Japan Maritime Self-Defense Force Akira Saito pointed out that China's maritime expansion and tensions in the Taiwan Strait and South China Sea, along with Russia's invasion of Ukraine and North Korea's ballistic missile launches, are undermining the international order and increasing threats in cyberspace and space. "I strongly believe that, facing this reality head-on, the role of the Japan Maritime Self-Defense Force is becoming increasingly important," Saito's statement reflects the multifaceted threats faced by Japan's defense authorities.

The situation in the Taiwan Strait is particularly serious. The People's Liberation Army of China has intensified military activities around Taiwan, making Japan's southwestern islands a de facto frontline. While South Korea does not have as direct an interest in the Taiwan issue as Japan, the impact of a Taiwan Strait crisis on the Korean Peninsula cannot be ignored. If U.S. forces focus on defending Taiwan, it could affect deterrence on the Korean Peninsula.

In this context, Japan and South Korea confirmed the maintenance of trilateral cooperation with the United States. The Camp David agreement signifies that the relationship between the two countries has transcended bilateral frameworks and has become a foundational element of the regional security architecture. The United States has long sought cooperation between its two allies, Japan and South Korea, but historical issues have posed obstacles. The current deepening of cooperation is an important achievement for the U.S. Indo-Pacific strategy.

However, there are also numerous challenges facing this agreement. The greatest concern is political sustainability. A presidential election is scheduled in South Korea for 2027, and if a change of administration occurs, there is a possibility that policies toward Japan may change. In the past, there have been significant differences in Japan policies between conservative and progressive administrations. The current Yoon Suk-yeol administration is actively pursuing improvements in relations with Japan, but there is no guarantee that the next administration will continue on the same path.

On the Japanese side, the transition from the Kishida administration to the next administration may also raise questions about policy continuity. The institutionalization of defense cooperation aims to mitigate the risks of such political fluctuations, but it cannot completely eliminate them.

Domestic public opinion is also an important factor. In South Korea, anti-Japanese sentiment still exists, and criticism of defense cooperation may rise, especially when historical issues or the Dokdo (Takeshima) issue come to the forefront. In Japan, there are also segments of the population that harbor distrust toward South Korea. Both governments need to make efforts to gain public understanding of the strategic necessity of defense cooperation.

The concretization of technological cooperation is also a challenge. While cooperation in AI, unmanned systems, and space has been agreed upon at a principle level, there are many issues to be resolved regarding specific projects, budget allocations, the scope of technology transfer, and the handling of intellectual property rights. In particular, sharing sensitive technologies requires careful consideration, and the stable operation of the General Security of Military Information Agreement (GSOMIA) is a prerequisite.

GSOMIA was temporarily announced to be terminated by the South Korean government in 2019 but was retracted at the last minute. This incident demonstrated how closely related historical issues and security cooperation are. Currently, GSOMIA is being operated stably, but the lessons of the past must not be forgotten.

The recent Japan-South Korea defense ministerial meeting and agreement represent an important step in the security environment of Northeast Asia. The resumption of joint training after nine years holds symbolic significance, and the exploration of advanced technology cooperation is forward-looking. However, the true test lies ahead. Can both countries overcome political fluctuations and the resurgence of historical issues to maintain and deepen institutionalized cooperation? The success or failure of this will impact the stability of Northeast Asia and, by extension, the security order of the entire Indo-Pacific region.

Strengthening trilateral cooperation among Japan, the U.S., and South Korea serves as an important countermeasure against China's expanding influence, Russia's revisionist actions, and North Korea's nuclear and missile threats. Will this agreement lead to substantial capability enhancement and strengthened deterrence, rather than remaining a paper promise? As analysts specializing in Northeast Asian security, we must continue to closely monitor future developments.