Introduction: A New Phase of North Korea’s Security Threat and Japan

Hiroyasu Akutsu
Hiroyasu Akutsu is a senior fellow in the Africa and Asia division of the Regional Studies Department of Japan’s National Institute for Defense Studies.

North Korea’s security threat has entered a new phase both regionally and globally. It has been almost twenty-three years since the so-called first nuclear crisis on the Korean Peninsula and almost twenty-four years since North Korea first test-launched what is believed to have been a Nodong/Rodong intermediate-range ballistic missile toward Japan. The series of Nodong/Rodong missile launches in 2016 has particularly reinforced Japan’s threat perception regarding North Korea’s nuclear and missile capabilities because of the country’s extremely rapid nuclear and missile development and the extension of its nontraditional offensive activities, including cyber, special forces, and other asymmetric capabilities, combined with its saber-rattling rhetoric against Japan.

While North Korea’s ability to put a nuclear warhead on a ballistic missile remains uncertain, the apparent progress that Pyongyang has made in its overall military technologies has only reinforced Japan’s threat perception about North Korea’s nuclear and missile development. In 2016, the Japanese Ministry of Defense recognized North Korea’s military build-up as “a serious and imminent threat” to the region and globe in its annual Defense of Japan white paper.1

It is increasingly important for Japan to maintain and enhance its alliance cooperation with the United States to further improve interoperability between the Japanese Self-Defense Forces (SDF) and the United States military, to promote Japanese-U.S. defense technological cooperation, and to strengthen trilateral defense cooperation with the United States and South Korea (ROK) through joint exercises.

Against this backdrop, this background paper will briefly discuss North Korea’s nuclear and missile development and its impact on regional security, especially from the Japanese perspective.2

The Military Strategy of the Kim Jong-un Regime: Enhancing the Military Leg of Byungjin

Since taking office after the death of his father, Kim Jong-il, in December 2011, North Korean leader Kim Jong-un has consolidated his power base through fear politics—purging whoever is seen as a challenge to his new reign—and by enhancing the military and strategic legacies he inherited. The new strategic line, called Byungjin, has worked as the de facto security strategy and military policy of North Korea under the Kim Jong-un regime. While Byungjin involves the simultaneous development of the economy and nuclear deterrence power, the latter has been prioritized. North Korea’s position as a nuclear-weapon state has been stipulated in the preamble of its constitution since 2012, and the Supreme People’s Assembly (SPA) adopted a law to further consolidate North Korea’s position as a nuclear-weapon state in 2013.3 The law, called the Law on Consolidating the Position of Nuclear Weapons State for Self-Defense, is arguably North Korea’s first-ever official nuclear doctrine. The law and the official statements issued after North Korea’s fourth and fifth nuclear tests suggest that North Korea aims to make the United States officially or unofficially accept North Korea as a nuclear-weapon state; enter into direct negotiations with the United States; and reach agreement that Pyongyang will ensure its full commitment to nonproliferation of its nuclear weapons and related material to other countries. Behind these objectives, there seems to be North Korea’s assessment that nonproliferation, not denuclearization, is the United States’s ultimate red line for North Korea.

North Korean Nuclear and Missile Capabilities

As for North Korea’s actual nuclear capabilities, there are many unknowns—but what is clear is that the country has made significant progress in the management and control of the environment for nuclear tests and the yield of nuclear explosions. It is hard to believe that the fourth test was of a hydrogen bomb due to the magnitude of the explosion, but the yield size of the fifth test was approximately 10 kilotons (kt).4 Compared to the yield size of the nuclear bomb that was dropped on Hiroshima (15kt), it should not be neglected as an amateur nuclear test.

Regarding North Korea’s goal of mounting a nuclear warhead on a ballistic missile, the country has not yet demonstrated such an ability—but due to the technological progress it has made in other areas, the accelerated pace of the whole nuclear program, and, above all, the country’s strong desire to achieve its strategic goal, no one can rule out the possibility that North Korea already has that capability.

More significant technological advancement has been made in North Korea’s ballistic missile program. North Korea has multiplied its missile types with different target ranges and strategic utilities, now including the Toksa/KN02, Scud B/C/ER, Nodong, Musudan, Taepodong I/II, KN08/14, and KN-11 (a submarine-launched ballistic missile, or SLBM). Except for the Taepodong I/II, their missile launchers are generally mobile. In addition, North Korea has suggested that it has tested a solid-fuel missile engine, which was likely applied to the SLBMs test-launched in 2016. The series of SLBM and Nodong missile launches this year were especially threatening because they were more difficult than before to detect. This poses a greater challenge to the existing U.S.-led BMD posture.

North Korea’s Conventional and Asymmetric Capabilities

North Korea’s existing conventional weapons are mainly aimed at the United States and South Korea, and they are largely outdated. About 70 percent of the Korean People’s Army (KPA) ground forces and 50 percent of their air and naval forces are still deployed within 100 km of the Demilitarized Zone, even under the Kim Jong-un regime. The absence of major upgrades for existing conventional weapons is no relief because the KPA’s large artillery force, with long-range 170-mm guns and 240-mm multiple rocket launchers, can still threaten South Korea’s northern area, including Seoul. Furthermore, North Korea has showed new ground-force equipment, such as tanks, artillery, armored vehicles, and infantry weapons.5

As for air and air defense, North Korea’s 1,300 aircraft are also outdated, but its surface-to-air missiles and anti-aircraft artillery have been partially improved. North Korea’s unmanned aerial vehicles can be used for precision strikes.6

North Korea’s naval force has been generally in decline, but it has been partially modernized. Particularly, as already mentioned, the North Korean Navy has been constructing a new submarine to carry SLBMs.

Finally, North Korea still relies heavily on its special operations forces and has strived to enhance its offensive cyber capabilities to compensate for or complement the weaknesses in its conventional capabilities and support the other offensive activities against the United States and its allies.

The Impact on Japan

Japan’s threat perception of North Korea’s nuclear and missile development has been reinforced over the past twenty-four years, since North Korea test-launched a Nodong/Rodong missile toward Japan in 1993. The 1993 Defense of Japan white paper stated that North Korea appeared to have been developing the Nodong/Rodong I, which was the likely identity of the ballistic missile that North Korea test-launched about 500 km toward the middle of the Sea of Japan.  With a target range of 1,000 km, the missile was likely launched in a restricted manner and could target Western Japan.7 Japan was “strongly concerned” about the possibility North Korea’s combined developments in nuclear and missile capabilities, as it would be a huge destabilizing factor to the international community as a whole.8

The so-called first nuclear crisis on the Korean Peninsula in 1994 heightened Japan’s concern and the twenty-three years of North Korea’s continued nuclear and missile development onward have reinforced Japan’s security threat perception. In the wake of a series of various missile launches by North Korea in 2016, the Japanese Ministry of Defense issued an indefinite order in August to destroy North Korea’s missiles and any fragments that enter Japanese territory. Particularly, the most recent launches of the three Nodong/Rodong missiles, which fell within Japan’s exclusive economic zone in September, have significantly worsened Japan’s threat perception. They were launched almost simultaneously from mobile transporter erector launchers. Fortunately, there were no Japanese fishing boats fishing in the area where the missiles fell—and what if there had been civilian airplanes flying in the area? The series of SLBM launches by North Korea has also increased the alert level of Japan’s national defense as Pyongyang has continuously been picking up the pace of their technological development. The general level and quality of North Korea’s military and dual-use technologies might still be far behind those of most Western and advanced countries, but the accelerated pace of development and improved capabilities that North Korea has demonstrated so far have forced Japanese Prime Minister Shinzo Abe to state at a press conference after North Korea’s fifth nuclear test, on September 9, 2016, that “North Korea’s recent nuclear test is a threat at a new stage. I believe that responses to it must also be completely different from those we have taken so far.”9 He also noted, “The role of China is extremely important.  I think we can say that China will truly be the key to putting these new sanctions into effectual execution . . . I strongly called on Premier Li Keqiang directly for cooperation on North Korean issues.  Going forward, I intend for us to continue to urge China at various levels to play an active role.”10

Future Prospects and Challenges

What will Japan do and how will it overcome challenges to its security by North Korea? The answer was largely already been given by Abe in his speech to the UN General Assembly on September 21, 2016:

North Korea has now manifested itself directly before us as an open threat to peace. What can we do in response? The raison d’être of the United Nations is now truly being tested. North Korea launched SLBMs. Immediately after that it fired three ballistic missiles simultaneously, each traversing 1,000 kilometers to reach Japan’s exclusive economic zone. It is purely a matter of good fortune that no commercial aircraft or ships suffered any damage during this incident. This year alone, North Korea has launched a total of 21 ballistic missiles. In addition, it claims to have successfully detonated a nuclear warhead in a test on September 9. . . . This series of launches of missiles and a detonation of a warhead does change the landscape completely. . . . We must therefore respond to this in a manner entirely distinct from our responses thus far. We must concentrate our strengths and thwart North Korea’s plans.11

The above statement accurately describes Japan’s policy direction in the diplomatic dimension. Abe also reconfirmed the continuation and importance of Japanese-U.S.-ROK trilateral ties. To include defense and security dimensions in the policy direction and reframe its strategic future, it is important for Japan to enhance extended deterrence through the following measures, some of which were already suggested in the upgraded Guidelines for Japan-US Defense Cooperation and have begun in response to North Korea’s continued military provocations since 2015:

  • Enhancing Japan’s own defense capabilities including tracking capabilities
  • Utilizing the Alliance Coordination Mechanism to further improve interoperability between the Japanese SDF and the U.S. Forces Japan
  • Promoting Japanese-U.S. defense technological cooperation
  • Strengthening Japanese-U.S.-ROK trilateral defense cooperation to further improve interoperability through joint exercises


It is increasingly important for Japan to maintain and enhance its alliance cooperation with the United States and to strengthen Japanese-U.S.-ROK trilateral defense cooperation through joint exercises to further improve interoperability—for example, by building on Pacific Dragon, the first-ever trilateral joint BMD exercise in June 2016.12 Fortunately, a long overdue military information agreement (the General Security of Military Information Agreement, or GSOMIA) was signed between Japan and South Korea on November 23, 2016. This should give a boost to Japanese-ROK security cooperation and help Japan, the United States, and South Korea improve interoperability.

Of course, since the Korean Peninsula is located at the intersection of major powers and the North Korean security issue requires coordinated and collective action among Japan, the United States, South Korea, China, and Russia, Japan should continue to seek cooperation with China and Russia as well. As North Korea’s belligerence will likely continue and more provocations are expected to come in the coming months, Japan and its allies should maintain and strengthen their readiness to respond accordingly.

Hiroyasu Akutsu is a professor and senior fellow at the National Institute for Defense Studies (NIDS).13


1 Japanese Ministry of Defense, Defense of Japan 2016 (Tokyo: Japanese Ministry of Defense, August 2016), 19,

2 For a similar paper by the same author, see Hiroyasu Akutsu, “Japan’s North Korea Strategy: Dealing With New Challenges,” Center for Strategic and International Studies, April 2014,

3 “Law on Consolidating Position of Nuclear Weapons State Adopted,” KCNA, April 1, 2013,

4 Anna Fifield, “North Korea Conducts Fifth Nuclear Test, Claims It Has Made Warheads With ‘Higher Strike Power,’” Washington Post, September 9, 2016,

5 Japanese Ministry of Defense, Defense of Japan 2016, 19.

6 Office of the Secretary of Defense, Military and Security Developments Involving the Democratic People’s Republic of Korea 2015 (Washington, DC: U.S. Department of Defense, January 5, 2016), 11.

7 Japanese Ministry of Defense, Defense of Japan 1993 (Tokyo: Japanese Ministry of Defense, 1993), (in Japanese).

8 Ibid.

9 “Press Conference by Prime Minister Shinzo Abe Following the 71st  Session of the United Nations General Assembly and His Visit to Cuba,” Prime Minister of Japan and His Cabinet, September 23, 2016,

10 Ibid.

11 “Address by Prime Minister Shinzo Abe at the Seventy-First Session of the United Nations General Assembly,” Prime Minister of Japan and His Cabinet, September 21, 2016,

12 U.S. Third Fleet Public Affairs, “Trilateral Pacific Dragon Ballistic Missile Defense Exercise Concludes,” U.S. Pacific Fleet, June 27, 2016,

13 The views in this paper are solely of the author’s own and do not represent those of the National Institute for Defense Studies or of any other institutions, including the government of Japan.