North Korea's Nuclear and Missile Development and Japan's Defense

Hideshi Tokuchi

1. Introduction: The Korean Peninsula and Japan's Security

Looking back over the past century of Japanese history, the importance of the Korean Peninsula to Japan's security is apparent.

The Sino-Japanese and Russo-Japanese wars were fought over interests in the Korean Peninsula. Japan's rearmament in the post-WWII era in the form of the creation of the National Police Reserve and the foundation of the Self-Defense Forces was precipitated by the outbreak of the Korean War. Today, the Japan-US Joint Statement of November 1969 is attracting renewed attention concerning the Taiwan issue; its Paragraph 4 begins with the perceptions of the leaders of the two countries on the Korean Peninsula situation. 1 It was over the Carter administration's attempt to withdraw US ground troops from South Korea that Masamichi Inoki wrote to US National Security Advisor Brzezinski that he wanted to knock down Undersecretary of State Philip Habib. 2 The 1997 "Guidelines for US-Japan Defense Cooperation" was discussed by many people in relation to Korean Peninsula contingencies, as the first North Korean nuclear crisis took place just before the release of the document. One of the reasons for formulating the legislation to deal with contingencies in 2002 was a North Korean armed spy boat incident. The National Defense Program Guidelines (NDPG) for FY2005 and beyond, which pointed to Japan's security in the post-9/11 era of international terrorism, was occasioned by Japan's introduction of missile defense system that was discussed mainly in relation to North Korean missiles. Many of the so-called 15 simulation cases presented by the Japanese government at the time of the security legislation to put the changes in constitutional interpretation into practice seemed to make one imagine Korean Peninsula contingencies.

Looking at changes in the NDPG, the current 2018 version is the first NDPG that put a section on China before that on North Korea, while in the NDPG for FY2011 and beyond and the NDPG for FY2014 and beyond, the description of North Korea appeared before that of China. Reviewing the description of the international security environment around Japan in different versions of the defense white paper, the present order of arrangement of relevant sections --- China, North Korea, and Russia --- first appeared in 2019. Until 2018 sections on the three countries had been carried as North Korea, China, and Russia.

Even though the advent of the Indo-Pacific era has driven the Korean Peninsula in one corner of the regional map and sometimes outside of it, the peace and stability of the Korean Peninsula claim emphasis as a matter of Japan's security. The fact that North Korea is a serious threat to Japan remains unchanged.

2. North Korea's Nuclear and Missile Capabilities

Today, North Korea is significantly inferior when it comes to conventional forces, and much of its equipment is obsolete. It seems that the country is attempting to compensate for its inferiority by concentrating on building up its weapons of mass destruction and ballistic missiles. 3

The Stockholm International Peace Research Institute (SIPRI) estimated the number of North Korea's nuclear warheads to be 30-40 in 2019-2020, but according to the 2021 edition of the SIPRI Yearbook, it has increased by some ten pieces over the past year to 40-50. 4 Japan's defense white paper of 2021 also points out that if North Korea were to restart its nuclear reactors, it could produce enough plutonium to make one nuclear bomb annually. 5 Siegfried Hecker estimates that North Korea possessed 45 pieces of nuclear warheads as of the end of the Trump administration. 6

As for the number of missiles possessed by North Korea, Japan's defense white paper of 2021 cites Jane's Yearbook estimate of 700 to 1,000 in total, of which 45% are Scud class, 45% are Nodong class, and the remaining 10% are other medium- to long-range missiles. 7 As for the number of launchers, the US Defense Intelligence Agency (DIA) report states many missiles as "undetermined." The same report estimates the total number of transporter erector launchers (TELs) to be over 200 in total: less than 100 for Scuds B/C (maximum range: 300-500 km), less than 100 for Nodong class (over 1,200km maximum range), less than 50 for Musudan class (over 3,000 km maximum range), and one submarine at least for Pukguksong-1 (over 1,000 km maximum range). 8

Japan's defense white paper of 2021 lists 18 types of missiles that North Korea has possessed and developed. 9 The breakdown of 56 ballistic missiles launched in the five years from 2017 to October 2021 is as follows: 10

2017 (17 in total):

Scud ER x 4, Improved Scud missile x 1, Pukguksong-2 x 2, Hwasong-12 x 3, Hwasong-14 x 2, Hwasong-15 x 1, and Unidentified x 4.

2018 (0)

2019 (25 in total):

Short-range ballistic missile A x 8, Short-range ballistic missile B x 4, Short-range ballistic missile C x 8, and Short-range ballistic missile (possible) x 4.

2020 (8 in total):

Short-range ballistic missile B x 2 and Short-range ballistic missile C x 6.

2021 (6 in total as of October):

New ballistic missile (North Korea claims a "new tactical guided missile.") x 2, Missile similar to short-range ballistic missile A x 2, New SLBM x 1, and Possible ballistic missile (North Korea claims a "hypersonic missile.") x 1.

North Korea is recently launching new types of ballistic missiles not known before. Although most of them are short-range missiles, technologies associated with solid fuels and irregular trajectory missiles will most likely be applied in the future to longer-range missiles. Although the current level of reliability of older missiles such as Nodong cannot be identified, if North Korea's missile development continues at this pace, missiles that would pose a direct threat to Japan will advance in performance and increase in number. 11 On top of this, there are concerns about the possibility of a hydrogen bomb being mounted on a missile, as well as apprehensions about more powerful warheads and the increasing difficulty of interception, should North Korea's allusion to a "supersonic gliding warhead" prove true.

3. Offense and Defense

There would be no end to the debate over which prevails in combat, offense or defense. Since strategic bombing did not necessarily produce the expected results during World War II, offensive superiority was put on the defensive. However, the idea of offensive superiority regained predominance following Japan's surrender in the wake of the atomic bombings of Hiroshima and Nagasaki. 12 Afterward, the United States proposed to the Soviet Union the limitation of anti-ballistic missile (ABMs) as it began the Strategic Arms Limitation Talks (SALT) with the latter. In 1967, the Soviet Union did not commit to the US theory that ABMs would cause strategic instability. In 1969, however, the Soviet Union came to aim at ABM limitations, which resulted in SALT1 in 1972. 13

Despite the signing of the ABM Treaty, the Soviet Union continued to build up its strategic offensive weapons. In the 1980s, the United States became aware that the Soviet Union had installed a large phased array radar at Krasnoyarsk, which the United States believed was "a critical part of a radar system designed to provide radar guidance for antiballistic missiles protecting the entire nation." 14 The United States noticed that the Soviet Union did not share the offensive superiority strategy. These developments led to the Strategic Defense Initiative (SDI) under the Reagan administration, which, however, was not put to practical use due to the immaturity of technology and cost increase.

On the other hand, the sinking of the Israeli destroyer Eilat by an Egyptian missile boat in July 1967 raised awareness of the need for anti-ship missile defense. This led to the development of the Aegis system, which now constitutes part of the ballistic missile defense system.

Today, many believe that a well-balanced possession and deployment of offense and defense without lopsidedness will lead to stability.

In particular, ballistic missiles are difficult to capture due to their eminently small radar cross sections. They are also hard to track because they fly at high altitudes at high speeds; reportedly, the speed of a ballistic missile with a range of 1,000km is Mach 10 at the time of impact, and that of an ICBM is Mach 20-30. Furthermore, ballistic missiles are hard to destroy by proximity fuse missiles. It is necessary to hit them directly. Consequently, powerful radars, high-speed and high-capacity computers, and precision guidance technology are all indispensable to intercept ballistic missiles.

A ballistic missile loaded with a nuclear warhead would cause far more devastating damages on humans, properties, the economy, and infrastructures --- compared to its carrying a conventional warhead. A ballistic missile loaded with a thermonuclear weapon would have still greater destructive power; the geographic area subject to damage would also be more extensive, and restoration would likely take a long time. Therefore, given a nuclear attack, the missile defense system must be 100 percent capable of intercepting a ballistic missile; if even a single ballistic missile slipped through the defense network, the result would be devastating.

North Korea's new ballistic missiles A and B are considered capable of traveling at lower altitudes than usual and with irregular trajectories; many believe that such missiles aim to breach missile defense networks. It is likely that the launch of lofted trajectory missiles detected since 2016 has been conducted primarily for data collection purposes. Yet, we cannot dismiss the possibility that those missiles could be fired toward Japan. Increased entry speeds make their interception difficult. 15

As for the interception of hypersonic missiles and irregular trajectory missiles, their flight altitudes and mobility will lower the probability of interception by existing missiles such as SM-3, SM-6, and PAC-3. Therefore, if we continue to deal with such new missiles with a missile defense system, it will be imperative to improve system capabilities or develop a new one. In the United States and Europe, numerous proposals have already come out on hypersonic missile interception systems. 16

4. Japan's Response (Discourses in the United States)

How to respond to such missile threats is what Japan must address. But the United States, as Japan's ally, has much concern about the Japanese response, on which the safety of US bases in Japan will depend and whether or not operations are possible from those bases. Since Japan began to discuss the possibility of possessing the so-called "enemy base strike capability," the United States seems to have become increasingly concerned about it. Reportedly, the United States was initially negative about Japan's possession of an "enemy base strike capability," but judging from recent discussions in America, at present she is not necessarily against it. 17

Regardless of which course Japan chooses to take on this issue, it is inevitable that Japan and the United States will build a joint response posture based on the Japan-US alliance; Japan will have to pay attention to US concerns. Next, I would like to introduce some discourses of American experts.

(1) Japan's "Nuclear Option"

Concerning Japan's "nuclear option," two choices would be conceivable: the possession of nuclear weapons by Japan and the US deployment of nuclear weapons in Japan. Some of the recent discussions on each of these are as follows.

Doug Bandow of the Cato Institute proposes "friendly proliferation" to Asian countries that are US allies, although his discussion is not focused solely on the North Korean threat. Skeptical about the reliability of extended deterrence, he argues that the possession of nuclear weapons by Japan, South Korea, and Australia is not a good strategy but would do the least harm, and that it could impose restrictions on North Korea' nuclear program, even if it could not make North Korea give it up. 18

In discussing North Korea's nuclear and missile threats, former Deputy Under Secretary of Defense Richard Lawless proposes that the United States should deploy nuclear-capable next-generation INF systems in Japan. He admits that North Korea's nuclear threat will remain for long as it is directed to Japan, the United States, and South Korea. His proposal stands on the idea that the reliability of US extended deterrence should be made more visible. He recommends a dual-key arrangement based on the premise of joint US-Japan command and control. In addition to the above, Lawless suggests another option with high survivability: the US-Japan joint operation of ballistic missile-carrying submarines and their deployment in Japan and Guam. 19

Former Secretary of Defense Chuck Hagel and others propose that the United States and its allies should seriously consider the forward deployment of nuclear-capable systems to deal with threats from, among other countries, North Korea. They also recommend: 1) Japan-US-ROK cooperation; 2) QUAD-ROK cooperation, and 3) the creation of a framework similar to the NATO Nuclear Planning Group (NPG) or an Asian Nuclear Planning Group, thereby including Australia, Japan, and South Korea in the US nuclear planning process. 20

(2) Japan's Possession of "Strike Capabilities"

In discussing Japan's response to the North Korean missile threat, Bruce Klingner of the Heritage Foundation points out the advantages of Japan's possession of "strike capabilities": those capabilities would impose greater costs on its adversaries, deter subsequent attacks, and provide some reinforcement to US capabilities; integrating such strike capabilities into the US-Japan alliance would mitigate Japan's concerns about the reliability of US extended deterrence. He also refers to the development of an upgraded, extended-range version of the Type 12 surface-to-ship missile. His proposal also includes mention of the division of roles between the two allies, following which Japan possesses cruise missiles to aim at fixed targets in North Korea, "while the United States maintains the mission of attacking North Korean mobile missiles." He also recommends strengthening Japan's missile defense, integrating Japanese "strike capabilities" into the Japan-US alliance, creating a Japan-US joint command, increasing defense spending, and promoting Japan-US-ROK cooperation. 21

Jim Hartman, a US Navy's liaison officer to the Japan Maritime Self-Defense Force, pointed out that in the development of its maritime defense capabilities, Japan has so far aimed at a force complementary with the US military, but it is now seeking to acquire the capabilities that overlap with those of the United States (amphibious warfare capabilities and "carrier-based" fighter aircraft). He argues that it is necessary to discern whether Japan is motivated by a political desire for a more independent maritime strategy or by rational military calculations. 22 Although Hartman does not discuss those overlapping investments by Japan as a response to the North Korean threat, his discussion implies many things to consider when looking back at political debates on Japanese "strike capabilities."

5. Japan's Response (Japanese Discourses on "Enemy Base Attack Capability")

When Japan began to consider the possession of "response capability to address the means of ballistic missile launches and related facilities" (so-called "strike capabilities" or "enemy base attack capability"), the topic was deliberated mainly in relation to North Korea's growing ballistic missile capabilities. The National Defense Program Guidelines for FY 2014 and beyond also covered this issue in that context. 23 Today, however, this topic is often discussed in relation to China's growing military power and the US-China missile gap.

For example, Sugio Takahashi argues that, as a matter of Japan's security following the expiration of the INF Treaty, it is necessary to rebuild deterrence postures in East Asia including one against the North Korean threat, and that to give high priority to systems with high strategic effectiveness, Japan and the United States should first set a direction at the level of military strategy and then discuss particular specifications and deployment sites for hardware. He suggests ground-launched ballistic missiles and hypersonic glide weapons as an imaginable option. 24

Satoshi Morimoto proposes the acquisition of ground-launched cruise missiles, subject to some preconditions, as a potential response to the strategic environment in which the US-China strategic rivalry will further intensify, especially in the sea and airspace surrounding Japan. 25

In order to make China understand that it will not be able to achieve its military objectives even if it attempts to invade the Senkaku Islands or Taiwan, Yoko Iwama and Masashi Murano propose the introduction of anti-ship cruise missiles to block the approach of Chinese naval vessels and that of ballistic missiles or hypersonic glide missiles to neutralize Chinese airbases located on the Chinese coast for a certain period. 26 In pointing out the costs of operating, maintaining, and improving the capabilities of missile defense, they argue that "as the adversary's missile capability improves in quantity and quality, costs for the defender to bear will increase proportionately; eventually, the defender will be in due course driven to face financial and operational limits." They add that "time is not favorable to Japan, given that North Korea continues to develop and increase production of new missiles while denuclearization is making no progress." 27

6. Revision of the "National Security Strategy" and the "National Defense Program Guidelines"

The Japanese government has recently announced that it will revise the National Security Strategy and the NDPG. It has also expressed its intention to "boldly engage in a reinforcement of our defense capabilities, including our... missile defense capabilities that include further effective measures." 28 It is not clear what this statement means. Yet, since Japan has been discussing "response capability to address the means of ballistic missile launches and related facilities" for the past eight years since 2013, Japan may not anymore be able to postpone a conclusion no matter what it may reach.

As stated by Iwama and Murano, "it is impossible to distinguish offense and defense in terms of those capabilities and actions necessary to deny an adversary the achievement of its tactical objectives. 29 Instead of a non-essential debate on what we should name those capabilities that have been called by different names such as "enemy base attack capabilities," "strike capabilities," and "counterattack capabilities," what we most need are expert and strategic studies and open discussions on the identification of capabilities necessary for Japan's national defense as a whole; the identification of priorities; the division of roles between Japan and the United States and the development of the necessary systems for that purpose; and the strengthening of industrial and technological underpinnings.

(Senior Fellow, National Graduate Institute for Policy Studies)

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