PHP Research Institute

Thinking about Deterrence for Japan and Stability in Asia

Japan Chair Fellow
Professor, National Graduate Institute for Policy Studies (GRIPS)
Japan's Ground Self-Defense Forces (JGSDF) soldiers during a live fire exercise at JGSDF's training grounds in the East Fuji Maneuver Area on May 22, 2021 in Gotemba, Shizuoka, Japan. (Photo by Akio Kon - Pool/Getty Images)
Japan's Ground Self-Defense Forces (JGSDF) soldiers during a live fire exercise at JGSDF's training grounds in the East Fuji Maneuver Area on May 22, 2021 in Gotemba, Shizuoka, Japan. (Photo by Akio Kon - Pool/Getty Images)

As China continues its rapid rise to power, the East Asian region can expect to see instability remain a fact of life for some time to come. What must Japan do to maintain the peace and prevent conditions from spiraling into conflict? What Japan needs now is discussion on the topic of deterrence. What would it mean for a nation like Japan, who until now has pursued “exclusively defense-oriented policy” (Senshubouei), to possess deterrent capability? This article takes a look at these issues, starting from the concrete threats that Japan faces today, and the costs entailed in acquiring such deterrent capabilities.

Missing in Japan: Strategic Communication Capabilities

On June 15, 2020, when then Minister of Defense Kono Taro announced that Japan would halt its planned deployments of Aegis Ashore missile defense systems, our hopes were that this would trigger a comprehensive, substantial debate on questions of deterrent capabilities for Japan. Since then, though, we have not seen things proceed as we hoped. The discussion of what systems should replace the originally proposed Aegis Ashore systems failed to show any creative exploration going beyond traditional defense frameworks. To make matters worse, in the end, the outcome was a decision to go with “Aegis equipped ships,” a solution that costs more both to implement and to operate.

The problem with missile defense is not the initial cost of acquisition, but the costs of operating and maintaining the necessary systems and improving their capabilities. Missile defense as it is envisioned today basically involves tracking incoming missiles and physically engaging each and every one of them to destroy them before they impact. This means that the defender must have at least as many interceptors as the number of missiles coming from the attacker—and preferably far more. An attacker, though, can take various countermeasures to overcome missile defense, such as by launching multiple missiles at once, or by including a number of decoys among them. This makes it a relatively inexpensive proposition to overwhelm a missile defense system. In short, this means that as an opponent’s missile attack capabilities improve in terms of quantity and quality, the defender side’s costs rise correspondingly. The defender will eventually run up against fiscal and operational limits to what it can do.

Today, although North Korea is in possession of nuclear-armed missiles, it refrains from actually using them. This is because Pyongyang understands that a full range of retaliatory measures by the United States and South Korea would be the consequence of such use. Missile defense in the case of a crisis on the Korean Peninsula, then, is meant mainly to prevent North Korea from misunderstanding the situation and thinking that cheap-shot blackmail, involving a handful of warheads and missiles, would be effective, as well as to limit the actual damage to the US and Japanese side should the North actually carry out a launch. Seen in this context, the enhancement of Japanese missile defense to date has boosted the resilience of Japanese society against the nuclear blackmail and contributed on the whole to deterrent efforts countering North Korea. But the fact also remains that while the denuclearization on the Korean peninsula has seen no progress, the North Koreans have continued developing and increasing their missile arsenal. It is clear that time is not on Japan’s side in this situation.

China, meanwhile, has come to present Japan with entirely different threats. Even if North Korea tries to effect a change in the current state of affairs, its territorial ambitions are limited to the Korean Peninsula. China, though, is seeking to expand its sphere of influence and change the status quo at every opportunity it is given, something that has been made clear by Chinese actions in the South China Sea. It is similarly clear that the same sort of development could unfold between China and Japan. The Japanese and Americans must work together to adopt a deterrent stance heading off a China that would take further actions to alter the status quo.

Deterrence as it functioned between the Soviet Union and United States during the Cold War relied, ultimately, on fear of full-scale nuclear war—namely, on mutual assured destruction (MAD). This has had the consequence of the concept of deterrence being tied closely to nuclear deterrence to this day. However, deterrence need not be solely nuclear in nature. In fact, it should entail all the elements that come into play when engaging in strategic communication with a potential adversary.

For many years Japan adhered to its “exclusively defense-oriented policy (Senshu bouei)” and the “basic defense force concept (Kibanteki Boueiryoku),” concentrating on itself rather than communicating with potential opponents when it came to crafting strategic approaches. Japan managed to fumble through the Cold War era, but today, this approach will not suffice. If Japan fails to deliver clear messages, and China interprets it as existence of power vacuum, it is certain to exploit them to expands its own sphere of influence. This is not something that Japan needs to consider solely in the context of control of the Senkaku Islands. Just as the Spratly Islands in the South China Sea, the Senkakus may be a symbolic stronghold in the East China Sea, but to a rapidly expanding China, they are but a little speck on the continuously widening map.

It is not for us to stop China’s rise to prominence on the world stage. Nor will this rise continue forever. In the near future, though, the pressure that Beijing’s rise brings to bear is certain to continue, and even if we enter the phase where Chinese power starts to wane, this will probably be accompanied by a lasting period of instability. Therefore, if we wish to maintain peace and avoid situations that may lead to a war, we must think seriously about deterrence.

Deterrence means dissuading someone from doing something by making them believe that the costs to them will exceed their expected benefit.1 Any moves on the part of the deterring part that serve to raise the costs of the opponent can be considered a part of its deterrent capabilities.

The Components of Deterrence

For most readers, the term deterrence likely brings to mind the idea of “deterrence by punishment,” whereby an action by an adversary is threatened by the prospect of a severe retaliation that is deemed to be unbearable. But we must also consider “deterrence by denial,” which seeks to prevent the opponent from undertaking certain actions by making it infeasible or less likely to succeed. A nation’s ability to continue fighting, which may include sufficient supplies of energy and food, or the will of its residents to resist an occupying force may be counted as important components of such deterrent capabilities.

Take Finland, for instance. This small nation on the border of mighty Russia found its soldiers pitted against those of the Soviet Union at the beginning of World War II. During the Winter War, Finnish soldiers strapped on skis, took to the woods, and wielded Molotov cocktails to put up a determined resistance against Soviet tanks, disrupting Joseph Stalin’s ambitions in the region. After the war, when other neighboring nations were absorbed into the Soviet sphere, Soviet memories of these experiences were a key element in the Finland’s successful maintenance of its status as a neutral, independent, and democratic state.

A robust civil defense is another element of deterrence. Toward the end of World War II in Europe, Britain faced the new threat of Germany’s V2 , the world’s first ballistic missiles. These missile attacks resulted in numerous casualties, particularly in and around London. At this time, though, Britain also developed an organized civil defense scheme, sheltering people in subways or by improvising other kinds of covers. The German plan to undermine Britain’s morale failed, and in the end, Germany saw the front lines pushed back to the heart of its territory until it was defeated. It is thus clear that national unity and the willingness of people to resist constitute important elements of a nation’s deterrent capability.

In the Japan-US security framework today, America’s extended nuclear deterrence—the “nuclear umbrella”—serves as the final guarantee deterring attackers. But the threat of nuclear retaliation is not an all-purpose tool that can dissuade every provocation an adversary might make.

A look at the patterns in Chinese actions to date shows that the country frequently takes an opportunistic and gradualistic approach to the expansion of its influence, beginning with minor provocative actions, probing how defender responds, and gradually encroaching on that defender’s interests, building up new normal. The “gray zone” warfare is typical of such an approach. The nuclear umbrella is insufficient on its own to deter actions like these. The threat of a nuclear strike is simply not credible, against actions such as China’s repeated intrusions into foreign territorial waters in the East China Sea with military and paramilitary “public vessels,” or its use of dredging ships in the South China Sea which continues to bring in sand. At the same time, China’s low-intensity actions aimed at altering the status quo are becoming increasingly bold, precisely because it is backed up by the confidence it has gained through modernizing its sea and air power, its missile capabilities, and its nuclear force.

For this reason, if Japan wants to halt China’s gradual efforts to change the facts on the ground in East Asia, it needs to wield a seamless set of deterrent measures, starting with the Japan Coast Guard’s patrol activities, encompassing various conventional warfighting capabilities of the Japan Self-Defense Forces, and ultimately going all the way to US nuclear deterrent capabilities.

A “Spear and Shield” Approach Past Its Prime

Today, the most important purpose of military power is not to wage war, but to deter it. However, if deterrence fails and an adversary starts with actions to change the status quo, the aim shifts to preventing that adversary from achieving its goals and restoring the status quo ante. In such a situation, the key question is whether a nation is able to proactively control the escalation ladders.

In the case of the Senkaku Islands, for example, we see frequent discussion of the importance of Japan’s capability to retake occupied remote islands. But this is just one facet of a broad range of deterrence and response capabilities. In order to prevent a situation where Japan needs to retake an island from arising in the first place, keeping the opponent’s landing forces from approaching that island is the primary task. The capability to deny such opponent’s activities—whether they are carried out by amphibious landing ships and transport helicopters carrying personnel, or by fighters and military vessels seeking to secure maritime and air superiority in a surrounding area—is another vital element of island defense.

The security relationship between the United States and Japan has long been described as one of “spear and shield,” with American forces handling offensive tasks and Japanese forces concentrating on purely defensive activities. This understanding is still valid in the sense that Japan depends on the United States for ultimate “deterrence by punishment” in the form of nuclear retaliation. At the same time, though, when it comes to the actions and capabilities necessary to prevent an adversary from achieving its tactical objectives, it is no longer possible to draw clear lines between offensive and defensive measures.

Taking the example of a missile warfare, the measures to be taken cover a wide range indeed. They include guiding civilians’ evacuation efforts to minimize casualties; relocating key facilities to underground or other locations with higher survivability; intercepting the incoming missiles with missile defense systems; the suppression of the fighter-bombers, maritime vessels, or mobile launchers that are the missile launch platforms; the destruction of the points of origin of those launch platforms (air bases and ports) and the ammunition and fuel depots, and other logistical sites supporting them; and the use of electronic and cyber attacks to interfere with the operation of the radar, satellite, and communication systems that the enemy uses to gain the targeting data. Whether we call each of these actions as “defensive,” “disruptive,” or “offensive” boils down to mere figurative; such distinctions have no real world significance. For this reason, the “spear and shield” description of the division of the allies’ responsibilities is losing its effective meaning.

The Strike Gap in the Western Pacific and How to Close It

Currently or in the foreseeable future, it is difficult to imagine a scenario where the United States would lose to the People’s Liberation Army, so long as it brings its full capability to bear. However, in limited theaters like Taiwan or the Senkaku Islands, where China could move to change the status quo within a short timeframe, the US forces available for immediate mobilization are limited to a relatively small number of forward-deployed forces in Japan and Guam, along with whatever carrier strike groups with Aegis destroyers are engaged in training in the region at the time.

The most asymmetrical facet in the military balance between the United States and China—and that capable of producing the most instability— is the capability gap of the ground-launched intermediate-range missiles, with a range from 500 to 5,500 kilometers. Under its Intermediate-Range Nuclear Forces (INF) Treaty with Russia, in effect until 2019, the United States was prohibited from possessing all intermediate-range missiles (including those with conventional warheads). During that period, China, which was not a party to the treaty, continued to enhance its capabilities in this area. (See Figures 1 and 2 above.)

The administration of US President Joe Biden has agreed to extend the New START (the Treaty between the United States of America and the Russian Federation on Measures for the Further Reduction and Limitation of Strategic Offensive Arms) with Russia. It has not, however, sought to bring the INF Treaty back into effect. National Security Advisor Jake Sullivan and Kurt Campbell, coordinator for the Indo-Pacific at the National Security Council, have argued that the United States should prioritize its investment in ballistic and cruise missile capabilities to counter China.

In the fiscal 2021 National Defense Authorization Act, the US Congress set forth the Pacific Deterrence Initiative. The PDI, which defines budgetary outlays for military activities and capability development in the Pacific region, treats investment in intermediate-range missiles as one of its top priorities. In Washington, there is a bipartisan consensus that conventionally armed intermediate-range missiles should be deployed in the Western Pacific as a way to strengthen deterrence against China.

None of this means that Japan should leave all the work up to the United States when it comes to enhancing the alliance’s deterrent capabilities. Firstly, despite the increasingly challenging security environment, the US defense budget has been unlikely to increase any further. Government spending in nondefense areas, primarily COVID-19 countermeasures, has risen rapidly, leading to a strong possibility that Washington will scale back its defense outlays in the coming years. Japan and the US will have to work more closely each other—not just by enhancing cooperation in alliance operations, but also by carrying out tighter coordination from the early stages of capability development and by striving to strike an appropriate mix in the offensive and defensive tasks and capabilities to be shouldered by each side.

Secondly, we must redress the balance in the competition with China in terms of the cost borne by each side for its defense. As things stand now, the more than 1,250 intermediate-range missiles in China’s possession would pose a serious threat to Japan’s SDF bases, American bases in the area and forward-deployed aircraft carriers. This has till now made it necessary for Japan and the United States to direct their limited resources toward costly missile-defense and early-warning systems.

China, meanwhile, is exposed to no risk from Japanese or American intermediate-range missiles. The carrier-based fighter aircrafts and bombers of the US do, of course, pose a threat. But the Chinese missiles may also have the effect of forcing US aircrafts in US bases in Japan or Guam, or on forward-deployed aircraft carriers, to withdraw temporarily out of their range. In this way, China can effectively slow down the tempo of US countering operations and thereby reduce its own costs of building and operating air defense systems. Should Japan and the United States deploy their own intermediate-range missiles, on the other hand, this would force China to shoulder additional costs for programs like missile defense.

Thirdly, if Japan develops its own offensive strike capability and intelligence, surveillance, and reconnaissance (ISR) capabilities, it will enhance its initiative in managing the escalation of contingencies as it also increases its voice at the table when it comes to policy coordination with the United States. In determining what sort of strike capability Japan should seek, we must not let the issue be simplified to a political debate on whether to accept US intermediate range missiles on Japanese territory. It is important that Japan has both the responsibility and the right to play a proactive role in the process of operational planning and its execution concerning when, how, and for what purposes it and the United States will use their offensive capabilities to manage escalation risk. The problem, of course, is that a Japan with no actual capabilities of its own will find it difficult to have its wishes reflected in this process. The same can be said of Japan’s relationship with the US/ROK Combined Force Command in case of a contingency involving North Korea. Strengthening Japanese capabilities is by far the best way to strengthen Japan-US integrated deterrence, much more so than any kind of nuclear sharing arrangement, which has a very small chance of actually being used.

The Strike Capabilities Japan Should Pursue

Japan must consider a range of scenarios when it comes to potential contingencies involving China. If we consider what is needed to prevent low-intensity crisis scenarios like the landing of Chinese fishing crews or maritime law-enforcement officials on the Senkaku Islands, the first step will be to enhance the personnel and capabilities of the Japan Coast Guard, such as by increasing the number of its patrol vessels or boosting its drone surveillance capabilities. If, however, China is confident that, even after escalation takes a situation out of the “gray zone” into the realm of a small-scale armed skirmish, it can overmatch the JCG and Maritime Self-Defense Force before the United States can get intervened, it will be more likely to increase the vigor of its provocative actions within that gray zone.

To ensure that the Chinese do not gain this sort of misguided confidence, it will take more than just enhanced JCG patrol capabilities. Japan must also enhance the MSDF’s capabilities to swiftly negate any Chinese efforts at escalation, thereby underpinning its national capability to handle situations arising in the gray zone.

Let us turn next to the mid- to high-intensity crisis scenario of a Chinese blockade of the seas around Taiwan or an attempted military invasion of the island. China’s first move would be to deploy its cyber warfare and electronic interference measures while also missile salvo to destroy airbases and port facilities in Japan and Guam. Having exhausted the US and Japanese missile defense resources in the region, it would then deploy its fighter-bombers and warships to establish sea and air superiority in the area up to the “first island chain,” seeking to deny access to US forces up to this perimeter. The upshot of all of this is that Japan’s task is to convince China that this set of military goals cannot be achieved.

As Japan prepares for the scenarios described above, there are two types of offensive strike capability it needs to consider. The first is antiship cruise missiles. In its 2018 National Defense Program Guidelines and Medium-Term Defense Program, Japan’s Ministry of Defense decided to introduce missiles in this category with relatively long ranges, including Joint Strike Missiles (up to 500 kilometers). These are all air-launched missiles, though, meaning they must be carried by F-35. Again, in the early stages of a serious contingency, China is likely to use its intermediate-range missiles to neutralize air bases and runways in Japan, preventing fighters from taking off. This means that the aerial assets Japanese and US forces are able to dedicate to antiship mission will be considerably limited.

In this situation, if the Ground Self-Defense Force is able to deploy ground- based antiship cruise missiles—with their higher survivability and longer range—it will be able to effectively prevent Chinese naval vessels from approaching from land bases in Japan. At the end of 2020, the Japanese government approved the development of improved Type 12 Surface-to-Ship Missiles with an estimated range of around 200 kilometers. If these GSDF cruise missiles are combined with Air Self-Defense Force antiship missiles and the ground-based antiship Tomahawks that the US Marines are seeking to add to their arsenal, and if they are improved with high-speed data links and given sufficient range (750 to 1,000 kilometers), it will enable the alliance to carry out saturation attacks from multiple directions on single targets.

The second type of strike capability to consider is ballistic missiles or hypersonic glide vehicles that can for a time neutralize some of China’s airbases located in its coastal areas. The Chinese have built up overwhelming numerical superiority in their land-based mobile missiles, making it impossible to sweep out this threat in the opening stages of a conflict. However, for China to maintain the safety of its transport and landing vessels in the East China Sea and the area surrounding Taiwan, it will also need to follow up its missile strikes with deployment of fighter aircraft to achieve air superiority. This needs to be followed on by naval control of the sea and achieve a blockade of Taiwan. On the other hand, even if China can inflict damage on the Japanese and US forces with its missile attacks, if it suffers damage to its own offensive counter air capability, it will find itself unable to achieve its military goals.

Unlike cruise missiles, which fly at only the speed of a passenger jet, medium/intermediate-range ballistic missiles travel at over nine times the speed of sound. At this speed, even conventional warheads can be delivered in long-range precision “sniping” on runways, hardened shelters and ammunition depots. If Japan-US forces stand ready to attack Chinese airbases, it can hamper China’s attempts to restore these facilities by posing an ongoing threat to them; it can also force the fighters and bombers in the air to return to more remote bases, resulting in an improved air combat situation for Japanese and US forces in the East China Sea and around Taiwan.

There are around 50,000 military and other key facilities in China that are potential targets during a conflict; of these, some 70% are located within 400 kilometers from the country’s coastlines. This means that if Japan equips itself with ballistic missiles with a range of around 2,000 kilometers, it will be sufficient (see Figure 3). Medium-range ballistic missiles with a 2,000-kilometer reach could be stationed in Kyushu and be capable of striking targets up to 1,000 kilometers inland from the Chinese coastline within 13 minutes after launch.

It would be difficult, though, to directly strike China’s time-sensitive targets such as mobile launchers with these land-based missiles. Cruise missiles are too slow for this mission, while ballistic missiles lack the dynamic targeting precision required. If Japan is to develop an approach capable of striking mobile launchers, this will rely primarily on precision guided munitions operated from aircraft. This leads to the need for several additional functions, including real-time intelligence, surveillance, and reconnaissance capabilities and suppression of an opponent’s air defense networks. Given the limited time and fiscal resources at Japan’s disposal, this is probably not a viable option.

Japanese defense, however, is something achieved via deterrence representing the total assets of both Japan and the United States. As US-Japanese defense linkages deepen at the early operational planning stages, it will lead to a reduced burden on the US forces, which will then be able to focus on more advanced missions such as mobile missile hunting. This will also keep China from miscalculating the possibility of decoupling Japan and the United States (and Taiwan), based on a belief that so long as it does not attack US interests directly, it will be able to decouple US from Japan. This, too, will bolster the alliance’s deterrent capabilities.

Deterrence is not something to be achieved through military force alone. We must also equip Japanese society with the ability to endure during the escalation phase leading up to a full-fledged crisis, enhancing its strategic resilience. This process will include legal and other institutional preparations for emergency situations, as well as enhancing civil defense capabilities. If the Japanese people fall into a panic and societal systems cease functioning, it will allow China to escalate a situation with extraordinarily little cost to itself.

Leading the Dialogue Toward East Asian Stability

The end goal of all of this is to prevent war. Toward this end, we must first think about forms of deterrence that involve balancing power against power to achieve equilibrium. The situation in which potential opponents, both of which are armed with advanced military capabilities, to remain in a tense relationship with one another is a risk in itself. We must therefore also consider mechanisms to enhance communication in times of crisis—not just with China, but also with Taiwan, South Korea, and other actors— in order to avoid accidental wars that nobody wants.

At the regional level, too, we must reaffirm the principle of seeking peaceful resolutions to conflict and explore the possibility of arms control and disarmament, while continuing to pay appropriate heed to the power balance in the region. It may be fruitful to look for examples to Europe in the Cold War era. From 1970 onward, European nations engaged in a wide range of dialogues, trust-building exercises, and forums and regimes for arms control and disarmament. Japan should play the lead role in forming similar forums for dialogue aimed at greater stability in the East Asian region.

Naturally, these actions will not bear immediate results. But diplomacy and security is very often about decades of hard work for the sake of that fleeting moment when the fruits of those hard work seems within your grasp.

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