The Debate

Rethinking Japan-South Korea Defense Relations

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The Debate

Rethinking Japan-South Korea Defense Relations

Both should recognize their common security agenda by initiating much closer bilateral defense and military technical cooperation.

Rethinking Japan-South Korea Defense Relations
Credit: U.S. Army photo by Cpl. Han, Jae Ho

South Korea and Japan have endured seven decades of profound distrust, but the time has come to acknowledge that the security concerns and wider geopolitical interests of both countries are very similar, and that this creates a significant opportunity for defense technology cooperation between their two militaries.

After their unfortunate history, replete with contrasting interpretations and political disagreements, it will not be straightforward to overcome such longstanding patterns of thought and behavior. Indeed, some innovative approaches will be required to resolve, or perhaps initially to sidestep, the entrenched misunderstandings and lingering trust deficit between South Korea and Japan. But there are considerable benefits available from enhanced military cooperation between the two militaries, and it is worth taking the trouble.

South Korea and Japan share a great deal in common: both are established democracies with liberal economies reliant upon advanced technologies and global trade. Yet military cooperation has always been very limited, and is generally mediated through their separate relationships with the U.S. military. Moreover, face-to-face encounters between the South Korean and Japanese militaries have often been blighted by their long history of mutual distrust, as witnessed by an incident that occurred last December involving a Republic of Korea Navy (ROKN) destroyer and a Japanese Maritime Self-Defense Force (JMSDF) patrol aircraft. The subsequent squabble encompassed the two defense ministries as well as the broader political sphere, drawing considerable media attention and reviewing many timeworn issues of bitter contention.

This may be helpful to those who want to sell newspapers, or to attract right-wing votes, but is it truly sensible to continue to rehearse these ancient quarrels between South Korea and Japan? Surely there are more urgent and important things to worry about: both countries face a serious potential threat from the rapidly expanding military might of China, and Russia is also resurgent, not to mention the continuing threat from North Korea.

So how can relations between South Korea and Japan be realigned with their shared geostrategic interests? Enhanced cooperation would clearly benefit both countries: better policy coordination is essential to encourage working collaboratively in their defense industries, in developing their military technologies, and in their defense-related scientific research. From such policy coordination in the military sphere, it is not unreasonable to hope for a more general rapprochement, which would allow South Korea and Japan to gradually escape from the predicament of their unhappy history.

There are several reasons why now is an appropriate time to improve military cooperation. First, there are clear signs that a new military and security environment is emerging in Northeast Asia: South Korean President Moon Jae-in’s administration is pursuing a peace initiative for the Korean Peninsula and North Korean denuclearization is under discussion. With continuing diplomatic engagement between the United States and North Korea, the aim is a peace treaty that establishes full diplomatic relations and leads to much closer economic relations between North and South Korea. History shows us that frozen conflicts can be resolved, and if change is coming to the Korean Peninsula then the military and security relationship between South Korea and Japan must also adapt.

Second, it is essential to recalibrate the ongoing defense reforms and military modernizations that both South Korea and Japan are undertaking. Changes to their visions and goals are required to accommodate the new concept of transactional security. U.S. President Donald Trump’s erratic and unreliable foreign and military policy, with its spurious “America First” justification, interprets South Korea and Japan as free-riders exploiting U.S. security cooperation. Now that the United States has taken such a perverse stance, however, it is surely time for the major stakeholders in the region, including the South Korean and Japanese militaries, to strive much harder to resolve existing disputes and to work to strengthen cooperative strategic approaches, especially by establishing operational and technical support for complementarity. Given budget constraints and the volatile security environment, it makes good sense for South Korea and Japan to identify and complement one another’s weakness and strengths.

Third, the character of the threats facing Northeast Asia is changing. The North Korean threat is obvious, but the threat from China and Russia is also ratcheting up, both in the aerial and maritime domains. There are increasingly frequent incursions into both the South Korean and Japanese Air Defense Identification Zones by Chinese and Russian long-range intelligence, surveillance, and reconnaissance (ISR) aircraft, and into confined maritime areas by their submarines. South Korea and Japan have common enemies; their militaries should work more closely together, and with other stakeholders. Many commentators have speculated that some kind of NATO-like structure will be needed to ensure future security for Northeast Asia. Multilateral security and military coordination needs to reach beyond the immediate region, and this could evolve naturally out of the existing multinational naval cooperation to monitor illegal ship-to-ship oil transfers between Chinese oil tankers and North Korean ships in the East China Sea. The United States, the United Kingdom, Canada, France, New Zealand, Australia, Japan, and South Korea all contribute surveillance aircraft and staff to support this operation, which implements a UNSC resolution to deter North Korean development of nuclear weapons and ballistic missiles.

Taken together, these reasons argue strongly for improved security cooperation between the militaries of South Korea and Japan, and for a more resilient dynamic in the broader relations between the two countries. They should also consider adopting some lessons from European security cooperation models, in particular various types of defense- and military-related technical cooperation in the joint design of naval ships and aircraft. It is probably too late to make such plans for the ongoing reforms, but at least the intention to commit to such cooperation should be articulated soon, so that future developments can enjoy the benefits.

European countries largely agree on defense and military approaches, and have a long history of close cooperation to build interoperable military assets. Collaboration on defense and military industry infrastructures has resulted in some very successful outcomes. European Typhoon fighters produced by function-sharing and technology-based defense industrial cooperation involves the U.K., Germany, France, Italy, and Spain. And the French and Italian navies have built FREMM Multipurpose frigates, a project that entails cooperation between the two countries’ shipbuilders.

Relations between South Korea and Japan have blighted by a long history of conflict, but other countries have managed to put such quarrels behind them. It is time to recognize that their common interests demand closer defense and military cooperation between them, and to move toward common acquisition policies and technical and defense industrial complementarity. There is a clear opportunity to work together on new military technologies, and also to develop dual-purpose technologies, by forging close links between the defense-related industries of South Korea and Japan. This kind of cooperation should go well beyond anything seen before, and can usefully contribute to a more general rapprochement, relaxing some of the historical bitterness and helping to rebuild trust between the two militaries.

There are already some helpful commonalities between South Korean and Japanese land, sea, and air platforms which can be further enhanced. Cooperation is feasible in a variety of areas, for example, main battle tanks, infantry fighting vehicles, armored personnel carriers, self-propelled howitzers, combatant ships and associated weapons systems, and stealth fighters. Defense industrial cooperation between the leading companies of South Korea and Japan is facilitated by their connections with major U.S. defense suppliers. Thus, both countries’ modern weapons and platforms rely upon supply-chains involving companies like Lockheed Martin, Huntington Ingalls Industries, BAE Systems, Boeing, L3, etc. Many defense-related companies in South Korea and Japan have long been developing dual-purpose technologies designed to adapt to indigenous weapons and systems, so this means that the two countries’ products already share considerable commonalities. Improvements in coordination should focus upon exploring the feasibility of defense-related industrial cooperation, purely in terms of military technology, rather upon national security per se.

There are several administrative procedures that can be gradually improved to realize joint defense and military technology development projects. At the policy level, the two ministries of defense and also their acquisition agencies should work to formulate general regulations and guidelines for technical cooperation between two countries. At the common acquisition level, the principal customers from the South Korean and Japanese armed forces should discuss joint development projects through bilateral military consultations, making use of existing arrangements, such as the three services staff talks and common training and education talks. Good candidates for bilateral development include naval strike missiles, joint strike missiles, torpedoes, and electronic warfare. As for R&D cooperation, the Agency for Defense Development South Korea and the Acquisitions, Technology, and Logistics Agency in Japan are similar organizations that could form a good partnership. Various companies can usefully cooperate, including HHI, DMSE, LIG, Hanwha, KAI, and Hyundai in South Korea, and Kawasaki, Mitsubishi and Fuji Heavy Industry, Komatsu, and Toyota Industries in Japan.

A future phase in defense cooperation would work toward the concept of joint operations based on a coherent bilateral military strategy between South Korea and Japan. Once enough commonality is established, it would make sense to integrate the two defense-acquisition agencies as a foundation for defense and military technology-related cooperation between the two militaries. This kind of military technology cooperation between the two countries can be, and should remain, a non-political issue between two friendly militaries cooperating for security purposes. Only by maintaining full independence of the process from sensitive historical and political problems can South Korea and Japan establish a real security partnership. Both governments should urgently recognize their common security agendas by initiating much closer bilateral defense and military technical cooperation. South Korea and Japan are both renowned for their technological innovation, so scientific cooperation in developing advanced weapons and systems would surely create a more flexible and robust security environment in Northeast Asia, and perhaps also in the Indo-Pacific region in the foreseeable future.

Sukjoon Yoon is a senior fellow of the Korea Institute for Military Affairs, and Navy Captain, Republic of Korea, retired.