Japan’s Counterstrike: Learn from South Korea

Japan and South Korea have had a historically difficult relationship. Yet, the two countries have recently increased cooperation and share an interest in working together on North Korea. One example is that Japan, South Korea, and the United States agreed in June 2023 to deepen cooperation on information sharing to deal with growing North Korea’s missile threats. This is a good first step. Then, looking at Japan’s defense policy, Japan announced that it would develop counterstrike capabilities to reinforce its deterrent last December. This is another good step to improve bilateral ties with the South Korean government. Nevertheless, these are not enough to deter North Korea, as it rapidly strengthens its strategic deterrent. The United States, Japan, and South Korea should strengthen trilateral defense cooperation. It is time for Japan’s defense practitioners to learn from South Korea about its investment in counterstrike systems, designed to hold North Korean missiles and command-and-control facilities at risk.

Japan has had heated debates regarding the development of counterstrike capabilities. This discussion dates back to the 1950s, when then-Prime Minister Ichiro Hatoyama expressed that Japan could strike enemy military facilities under certain restrictions. Yet Japan had chosen not to develop counterstrike capabilities until this time. In its latest defense white paper, the Japanese government states that “the government has traditionally interpreted a point in time when an armed attack on Japan occurs as when the opponent launches an armed attack and has interpreted that we do not have to wait for suffering actual damage by an armed attack. Japan’s use of military force after the opponent launches an armed attack is different from the so-called preemptive strike by which the enemy country is attacked before its armed attack occurs.” Those in Japan with concerns over counterstrike capabilities often see the problems in whether Japan (with support from the United States) is able to detect the signs of the enemy launching an armed attack against Japan. This is a very important point, but it is not the focus of this article — rather, this piece explores more about operational challenges when an opponent actually launches an armed attack and fires missiles against Japan.

There are two main areas where Japan should learn from South Korea in terms of counterstrike. First, Japan should make its counterstrike doctrine concrete and aligned with that of South Korea to jointly address North Korea’s threats. In doing so, Japan needs to clarify the ultimate ends and respective means of its counterstrike capabilities, referring to and coordinating with South Korea’s Three Axis system. Second, Japan should establish joint command-and-control systems specialized in counterstrike capabilities. Toward this goal, Japan should consider creating a strategic command under the direct control of the standing joint command that will be established in 2024, or could grant authority to control counterstrike systems to its ad hoc joint task force responsible for ballistic missile defense.

South Korea’s Strategic Deterrence

Japan relies on U.S. extended deterrence and its own missile defense systems for strategic deterrence. Yet, as Japanese strategists write in the National Security Strategy, missile defense is not enough to deal with the current security environment. Countries have been building up large, sophisticated missile forces in the Indo-Pacific region. Japan is planning to invest in a slew of counterstrike capabilities, which are expected to attack enemy missile launchers and military facilities to reduce the number of missiles flying to the Japanese homeland. Japanese counterstrike capabilities and missile defense systems are intertwined and essential parts of strategic deterrence.

Faced with more serious North Korean military pressure, South Korea has gone further than Japan in terms of deterrence doctrine. South Korea started looking for missile capabilities much earlier than its neighbor — back in 1978, it successfully launched a Baekgom (백곰: polar bear) missile. Today, South Korea has developed the Three Axis system, which consists of Kill-Chain, Korea Air and Missile Defense, and Korea Massive and Punishment Retaliation. As Clint Work explained in these pages, these missile systems and sensors are designed to react to North Korea before, during, and after a missile attack. First, Kill Chain is a preemptive strike when South Korea detects signs of imminent attack, targeting North Korean artillery and missile silos. Second, Korea Air and Missile Defense is a multi-layered missile defense concept to intercept flying ballistic missiles. This includes the Patriot, Navy Aegis systems, and Terminal High Altitude Area Defense missile defense systems. Lastly, Korea Massive and Punishment Retaliation is a plan to attack Pyongyang and remove the North Korean political and military leadership. This response is much stronger than Kill Chain and is aimed at deterring North Korea’s employment of nuclear weapons by the threat of conventional but punitive retaliation. South Korea would use its ballistic and cruise missiles as a main means to strike, including Hyunmoo (현무) missile systems. To oversee these systems, South Korea will establish Korea Strategic Command in 2024 to effectively operationalize the Three Axis system. This command would control strategic weapons and missile defense.

This Three Axis system is central to South Korea’s deterrent against North Korea and was developed, in part, due to South Korean concerns that the U.S. response to a regional crisis may be delayed, or come after a North Korean attack. The discussion between South Korea and the United States about wartime operational control transfer attests to these concerns — South Korea will not regain operational control until it operationalizes the Three Axis system. Control was originally transferred to the U.N. Command during the Korean War and then to the South Korea-United States Combined Forces Command. In the past, the United States needed operational control of the South Korean forces to deter North Korea from invading the South again and to keep Seoul from launching its own attack to reunify the peninsula. Today, by contrast, as North Korea’s missile forces are growing, the United States is welcoming South Korea’s defense buildup. The United States also removed the missile restriction agreement with South Korea in 2021, which has reinforced the Three Axis system.

Challenges of Japan’s Counterstrike Capabilities in Dealing with North Korea

Japan declared it would look to possess stand-off weapons as a counterstrike means. This includes purchasing Tomahawk missiles and making its Type-12 surface-to-ship missiles longer-range and available from air, sea, and ground platforms. Japanese leaders are also considering making improvements to intelligence, surveillance, and reconnaissance capabilities to enhance targeting capabilities for these missiles. These are undoubtedly steps in the right direction. However, Japan still faces two challenges.

First, Japan must clarify its counterstrike doctrine. Both Japan and South Korea have invested well in missile defense. However, as mentioned earlier, while South Korea’s strike system has two axes (before and after missile attack), Japan’s doctrine for counterstrikes on adversary targets is less clear. The National Security Strategy indicates that these forces would be used in a lawful way based on domestic and international law and follow Japan’s three standards of using force. This means that any strikes will strive to use the minimum amount of force necessary and Japan’s strike would come after an enemy’s launching of an armed attack (as mentioned earlier, this does not mean Japan has to wait until missiles cause damage to the Japanese soil). Yet, Prime Minister Fumio Kishida did not clarify under what situations Japan could launch preemptive counterstrike. Again, this is “preemptive counterstrike” —preemptive because this occurs before an adversary fires missiles against Japan, but this is still counterstrike in the sense that Japanese reaction happens after the enemy launches an armed attack.

This omission could be an attempt at “strategic ambiguity,” designed to deter North Korea by intentionally blurring Japan’s redline. Nevertheless, defense practitioners should be capable of launching preemptive counterstrike in case intelligence shows signs of imminent attack from North Korea and responsible civilian policymakers have made that decision. Defense planners should start by splitting the capabilities into preemptive and retaliatory counterstrike, and then should explore what weapons should be used to attack what targets. South Korea already clarifies what targets and means would be used when its military conducts the Kill Chain and massive punishment options. Once Japan materializes its counterstrike doctrine in this way, Japan and South Korea will both benefit from holding consultative processes on targeting, or how to make the most of two countries’ assets in a timely and proportionate manner.

This will enable Japan and South Korea to jointly control escalation and deter North Korea from crossing the nuclear threshold. In other words, if Japan and South Korea do not coordinate their counterstrike doctrines and one of them conducts a counter-value strike before North Korea launches its missiles, North Korea has a good reason to escalate to the nuclear dimension and could strike both countries. Of course, this conversation will be useful to the United States too, as long as the United States would command Korean forces in the event of a conflict. There are multiple existing mechanisms for Japan or South Korea to have this dialogue on a bilateral basis with the United States, but the emerging trilateral nuclear consultation group will be the best place to have this targeting discussion, even though Japan and South Korea’s strike means remain conventional.

The second challenge is command and control. South Korea will soon establish the Korea Strategic Command, but Japan currently has no plan to make an equivalent command. The military’s future counterstrike capabilities will be dispersed in the Ground, Maritime, and Air Self Defense Force. Japan should establish joint headquarters to command and control these strategic strike systems in a timely and appropriate manner. This is particularly necessary if Japanese missiles forces are asked to destroy North Korea’s missile launchers prior to an attack. One way to establish a strategic command is to place it under the direct control of the standing joint command that the Self Defense Force will create in 2024 to facilitate joint operations overall. If it is difficult to have a permanent strategic command politically, Japan could develop its ad hoc ballistic missile defense task force into a counterstrike and missile defense task force. The task force is organized to counter ballistic missiles, having a commander of the Air Defense Command from the Air Self Defense Force as its head. This task force includes missile defense units from three services, connecting them with the detection and information-sharing system, called the Japan Aerospace Defense Ground Environment. It would be politically and financially more feasible to integrate counterstrike capabilities, such as the Type-12 surface-to-ship missiles and Tomahawk missiles, in this ad hoc task force than it would be to establish a new strategic command. Though ad hoc, this would make the commander of the Air Defense Command responsible for counterstrike operations and enable him/her to have a conversation with the commander of Korea Strategic Command.

Conclusion

As Japan increases its defense prowess, it has taken a major step: developing counterstrike capabilities. However, Japan should focus not only on purchasing and developing weapons, but also on its strategic doctrine and command and control to achieve deterrence goals. South Korea has already begun operationalizing its strategic systems, and Japan should learn from its neighbor. Firstly, Japan must work on its counterstrike concept to clarify the timeline of operations and targets that Japan should attack in each time phase. This should be in coordination with South Korea’s Kill Chain and massive retaliation options to control escalation against North Korea. The nuclear consultative body that the United States seeks to establish would be a great venue for this joint targeting planning. Furthermore, Japan should create command-and-control systems specialized in counterstrike and missile defense. It would be preferrable to have a standing strategic command, similar to that forthcoming in South Korea, but if this is difficult then an ad hoc strategic task force, developed from the joint task force for ballistic missile defense, would suffice. Having a single commander overseeing Japan’s three services’ counterstrike capabilities would facilitate helpful consultative processes on targeting with South Korea.

Shinichi Hirao is an officer of the Japan Ground Self Defense Force. He has been in service for eight years and his research interests include nuclear and conventional deterrence, including Japan’s counterstrike capabilities. He received his B.A. in Law from the University of Tokyo and the Master of Public Policy from the University of Virginia.

The views and opinions expressed here are the author’s own, and do not reflect those of any organization with which the author is or was affiliated.

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