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  • Ryo Hinata-Yamaguchi

Japan Struggles with Its Pacifist Heritage Amidst Intensifying Geopolitical Tensions

Growing threats from China, Russia, and North Korea have forced Tokyo to reassess its strategic stance. Yet without escaping the multiple constitutional, political, economic, and demographic constraints on its military buildup and the use of force, Tokyo will continue to struggle in its attempt to adapt to the changing security environment

A Japanese military helicopter lands on the deck of an American warship during a joint exercise in the Philippines Sea, 2020 | Photo by Lance Cpl. Joshua Sechser (public domain)

The waters around Japan’s Island are growing increasingly troubled in recent years – and as a result, so are its government and armed forces. In the last quarter of 2021 alone, approaching Chinese bombers repeatedly forced Japan to scramble fighter jets for interceptions,[1] North Korea fired suspected submarine-launched missiles into the waters off Japan’s west coast,[2] and Russia deployed coastal defense missile systems near Pacific islands also claimed by Tokyo to underline Moscow’s firm stance in the Northern Territories dispute.[3]

These escalations, alongside recent developments in the geostrategic landscape and advancements in hybrid warfare and military technologies, present the most direct concerns to Japan’s national defense apparatus in recent decades. Tackling them will require Tokyo to address several thorny issues: constitutional reforms, military force structure rebalancing, and weapons procurement. While progress has been made in recent years on all these fronts, Tokyo’s attempts ultimately may not be enough to keep up with the rapid changes in its neighborhood.

This article has two goals: to unpack Japan’s most pressing national security and geopolitical threats, and to consider ways for Japan to advance its national interests and maintain its security and prominent role in the Asia-Pacific.

Japan’s National Defense Concerns­

Located in the Pacific Ocean off the east of the Eurasian continent, Japan is an archipelago that stretches from the Sea of Okhotsk in the north to East China and the Philippine Seas down south. Due to the nation’s location and trade-oriented, resource-restricted economy, much attention is traditionally given to the safety and stability of sea lines of communication (SLOC).

Japan’s approach to national security in the past 70 years has been primarily shaped by Article 9 of the post-War pacifist constitution, which was dictated to Tokyo by the occupying American forces in 1947 but has since become entrenched in the country’s political culture. Article 9 essentially outlaws the use of military force by the government and restricts its authority to maintain land, sea, and air forces with war making capabilities. Article 9 has remained untouched since it came into effect in 1947 and its provisions severely limit the government’s ability to deal with contemporary threats.

The most serious threat today comes from China, due to its assertive actions toward Japan and the region, particularly in the East and South China Seas as well as the Taiwan Straits. Moreover, the rapid modernization of the People’s Liberation Army (PLA) and enhancements in hybrid warfare capabilities (see below) amplify the gravity of the threat it poses to Tokyo. Lastly, China has gained greater confidence in wielding an increasingly assertive posture towards Japan concerning the Senkaku Islands (“Diaoyu Islands, 钓鱼岛” in Chinese) and towards Taiwan.

For Japan, China’s show of force against Taiwan is of grave concern, not only since the democratic island is an immediate neighbor to the Japanese archipelago, but also because of the likelihood that Beijing will strike U.S. forces stationed in Japan should conflict break out.

Moreover, hybrid warfare – utilizing both conventional and unconventional means of attacking, or at least exploiting, the opponent – is becoming a sign of the times. Given that such operations take place in “gray-zone” situations that blur the line between war and peace, Japan’s constitutional constraints make it difficult for it to effectively respond in a timely manner – not simply on the ground, maritime, and air domains but also in cyber and outer space domains. Compounding the problem is the fact that Japan is situated within what, according to American military doctrine, can be called China’s continuously growing Anti-Access/Area Denial zone (A2/AD). This puts the archipelago directly in the line of fire and at the risk of the Japan Self Defense Forces (JSDF) being numerically overwhelmed.


In October 2021, Chinese and Russian Navy warships transited through the Tsugaru Strait – which Tokyo read as a direct provocation


To better counter this growing threat, Japan has turned to multilateral frameworks. Concerted actions by states towards China have added new colors to the Indo-Pacific geopolitical dynamics. Since the late 2000s, Japan has worked with the US, Australia, and India to establish and develop what has become the Quadrilateral Security Dialogue (the “Quad”), which was re-established in 2017. While the Quad is still a loosely structured framework that falls short of being an alliance, it nevertheless serves as an important component for Tokyo’s objective of achieving a “Free and Open Indo-Pacific.”

The recently established trilateral security pact between Australia, the United Kingdom, and the US (“AUKUS”) has been a topic of much interest in Japan. Although “AUKUS” itself is exclusive, the potential exists for Japan to coordinate with members of the pact. However, such multilateral efforts have led to intensified reactions from China and to mixed responses from other Indo-Pacific states that pursue more hedging strategies, consequently flaming tensions in the region.[4]

North Korea’s threat to Japan has grown substantially in recent years, due to Pyongyang’s continued modernization of the Korean People’s Army (KPA).[5] While the KPA’s progress is far less impressive than that of the Chinese PLA, North Korea now possesses a diverse range of both cruise and ballistic missiles capable of striking Japanese and American forces stationed in the Indo-Pacific, as well as cyber warfare capabilities.[6] Moreover, uncertainties over the fate of North Korea, such as regime instability or collapse, also raise concerns for Japan, with the risks of military conflicts and a human security crisis in the adjacent Korean peninsula.

Concerns also persist surrounding Russia. Tokyo has unresolved disputes with Moscow over the four islands known as the Northern Territories that have been unilaterally occupied by Russia since 1945.[7] Nowadays, there are renewed concerns over the Kremlin’s provocative mobilization of its armed forces. Air and naval incursions by Russia are not uncommon, and there are concerning developments including the deployment of fighter aircraft and anti-ship missiles to the military bases on the disputed islands of Etorofu and Kunashiri.[8]

Furthermore, Japan also fears the possibility of getting embroiled in Russia’s hostility towards the U.S. and its allies. It is also cognizant of the increasing strategic coordination between Beijing and Moscow. This cooperation was displayed in October 2021 in direct provocation against Japan, when Chinese and Russian Navy warships transited through the Tsugaru Strait, a narrow, 12-mile-wide strait that separates the main Japanese island of Honshu from the northern prefecture of Hokkaido.[9]

Beyond these immediate geostrategic concerns, there are also threats that are far from Japan itself, but nevertheless directly or indirectly affect the nation’s security. Given the location of critical resources and transport routes, Japan is acutely sensitive to geopolitical conflicts, such as the one raging in Ukraine at the time of writing. It is also vulnerable to terrorism and transnational crime in the Middle East, Africa, and South and South-East Asia.

Technological developments are also creating greater complexities. Militarily, new weapons technologies being pursued by states as part of their military modernization programs are transforming warfare. This is particularly true with hypersonic and laser weapons, robotics, and the application of information and communications-based technologies such as artificial intelligence and quantum computing.

Yet Japan’s problems are not only limited to military innovation. The intense competition among states to attain technological superiority have exacerbated not only geopolitical tensions, but has also placed additional pressure on already-strained global supply chains. While Japan is indeed acknowledged as a technological powerhouse, it nonetheless finds itself facing greater technological competition as well as growing economic vulnerabilities, particularly with the current global supply chain crisis.

Given these recent developments and emerging realities, Tokyo needs to significantly reconfigure its strategic thinking and pay greater attention to how it can better defend itself and manage the growing threats it faces. However, it finds itself constitutionally stiff where flexibility is most required.

Defense Planning Constraints

The National Defense Program Guidelines (NDPG) is the central defense strategy and planning doctrine of Japan. While the NDPG is designed to be effective for a ten-year period, over the past two decades the document has undergone multiple significant revisions within increasingly shorter periods of time.

During the Cold War, Japan’s defense posture was based on the minimalist Basic Defense Capability concept that remained largely unchanged for decades. But facing the new geopolitical uncertainties of the post-Cold War era, Japan issued new NPDGs in 1995 and 2004, accelerating the momentum toward not only a more proactive defense posture, but also the nation’s international security role.


Arguably the most significant obstacle to Japan’s defense planning is the Constitution’s Article 9


Key developments followed in the 2010s, starting with the 2010 NDPG that vowed to make the JSDF better prepared for mobilization. The 2013 NDPG, formulated by the new Abe Shinzo government, was the first to advance a proactive posture toward international security and a more offensive-oriented approach to national defense.

Consequently, important legal reconfigurations for removing some of the barriers emanating from the constitution have been pursued. In particular, the revised legal conditions for the use of force,[10] and the passing of the Legislation for Peace and Security in September 2015,[11] granted the Japanese government the authority to exercise the right of collective self-defense for the first time since the end of World War II. It also granted the JSDF greater flexibility to mobilize – albeit still under enormous restrictions compared to other states, due to constitutional restrictions.[12]

Still, security challenges outpaced the advancements in Japan’s national security strategies and readiness, compelling Tokyo to revise the NDPG again in December 2018. The latest NDPG vowed to make the JSDF more proactive and ready to work with a wider strategic coverage by making a “Multi-Domain Defense Force.”[13]

Despite advances in its strategies and defense readiness, as well as the alliance with the United States, Japan still feels it is still insufficiently prepared to adequately deal with current and projected threats and vulnerabilities. Thus, the current Kishida Fumio administration is pressing ahead to revise both the NDPG and the National Security Strategy (NSS) documents by the end of 2022. Yet without addressing the myriad of political, social, and legal issues that have constrained the advancements in Tokyo’s defense policies, strategies, and readiness, Japan will continue to lag behind its regional rivals.

A difficult path

The first and arguably most significant obstacle is the Constitution’s Article 9. Beyond straightforward legal constraints on force structuring and defense spending, it has also affected Japanese politics to the point where constructive discussions on national defense issues have been kept low-profile or even treated as a taboo for many decades. While greater recognition of the urgent security threats has led to increased debates about national defense and even constitutional reform, actual progress has been incremental at best, as seen with 2015’s Legislation for Peace and Security, which was squeezed out in limited form after prolonged political battles.

Second, is a unique aspect of the Japanese budget – the self-imposed 1% of gross domestic product (GDP) cap on defense spending, set in 1976 by the Miki administration as a political demonstration to avoid excessive spending. The cap not only limits force structural investments, but also consumption costs for operations and maintenance.

Given that Japan is the third largest economy in the world, the defense budget is by no means small in absolute numbers. Tokyo has continued to set new record highs for the past seven years, and the provisional budget for the 2022 financial year stands at 5.4 trillion Yen (approximately $47.2 billion), which ranks Japan about ninth in world in military spending.[14] That said, in this author’s opinion, the current budget falls short of what is required for Japan to adequately deal with the threats it is facing.

Furthermore, recruitment to the JSDF is heavily affected by the persistent demographic crisis, marked by low birth rates and aging population.[15] Moreover, the economic recovery in recent years has ironically negatively affected the JSDF’s recruitment and retention, since young adults prefer joining the private sector or other government positions rather than the armed forces.

Compounding the long-standing problem is the composition of the JSDF, which disproportionately favors ground forces, even though current defense demands concentrate on the air and naval domains. The Japan Ground Self-Defense Force has 140,646 servicemen and servicewomen, while the Japan Maritime Self-Defense Force and Japan Air Self-Defense Force only have 43,033 and 44,152, respectively.[16] Although rearranging service branch composition and boosting personnel would take years, failure to correct the imbalance would only lead to greater gaps in dealing with the growing threats in the air and maritime domains.

For Japan, these constraints create severe dilemmas in defense planning that consequently affect its strategic readiness. Indeed, the growing uncertainties and urgencies have justified the efforts to overcome, or at least mitigate, those barriers to genuinely enhance Japan’s security. Yet still, the challenges in doing so remain large and the momentum has been far from fast.

Map of South-East Asia. The deterioration of Japan’s relations with three of its neighbors is a worrying trend | Source: Daniel Feher, FreeWorldMaps.Net (with permission by the author)

Steps Ahead

The key question going forward is how Japan can sharpen and strengthen its defense readiness against the intensifying, multifaceted threats it faces in the most cost-effective fashion. With the current Kishida Fumio administration pressing ahead to revise the NSS and the NDPG by the end of 2022, there are several items that warrant particular attention.

First, the shift toward more offensive measures is long overdue. One topic currently under debate is the legal and operational plausibility of striking enemy bases when Japan is under attack, or when such attacks are imminent.[17] Indeed, there are caveats, particularly with questions over whether offensive means go against Japan’s rules for measures that are to be “exclusively defense-oriented” and “minimum necessary.” But the other is that Japan is still far from being able to launch full-fledged offensive operations due to the costs of acquiring and operationalizing new systems, including enhancements for air and naval supremacy, cyber and electronic warfare, as well as limited strike capabilities against enemy bases. Thus, for the foreseeable future, the improvement in the JSDF’s offensive measures would be incremental and somewhat limited, making Japan dependent on the U.S. for strategic strikes.


Demographic problems require Japan to make the most of advanced technologies, including increasingly automated and unmanned platforms


Second, asymmetric methods would also be vital for the future of the JSDF. There is much to exploit in the cyber and electromagnetic domains (which are also governed by Article 9 restrictions), as in maritime operations – particularly in submarine and naval mine warfare. Of course, the pursuit of gaining an asymmetric edge is not about discounting high-end, heavy-duty assets such as next-generation aircraft and vessels or missile defense capabilities, that will remain the mainstay of the JSDF.[18] Rather, it is about combining a variety of capabilities and tactics to circumvent the JSDF’s shortfalls while exploiting the vulnerabilities of qualitatively and quantitatively superior opponents.

Third, the demographic issues require Japan to make the most of advanced technologies. Some encouraging developments are already seen with the pursuit of unmanned ground, maritime, and air vehicles for surveillance and reconnaissance, and AI is also expected to play a vital role in cyber defense operations.[19] Moreover, advancements are seen in manned platforms, such as the case of the recently commissioned 3,900-ton Mogami-class frigates that are equipped with automated systems and require only approximately 90 crew members to operate. While there are indeed limits to the extent in which technologies can offset the human resource demands and burdens, they are nonetheless one of the few means to qualitatively enhance the JSDF’s readiness.

Fourth, jointness continues to be undermined by differences and rivalries among the JSDF branches, as well as bureaucratic stove-piping. The JSDF still does not have permanent joint commands, consequently overstretching the Joint Staff Office and undermining seamless mobilization. Moreover, while joint training and exercises have improved, joint operational doctrines remain nascent. Hence the key agenda would be to establish joint commands with contextualized doctrines according to the areas of operation.

Fifth, much also needs to be done regarding alliances and international security cooperation networks. Without doubt, the Japan-US alliance has significantly strengthened in recent years.[20] That said, there is still much room for further improvement, especially in strategic, operational, and tactical doctrines, intelligence-sharing, as well as fine-tuning interoperability. Moreover, the future of the Japan-US alliance is also about deepening technological cooperation, particularly in new and emerging technologies.[21]

Another key question is how the alliance can strengthen multilateral networks with other US allies and likeminded states in the Indo-Pacific and beyond. Japan would need to enhance its security cooperation and coordination with key actors, including Australia, Canada, India, South Korea, Taiwan, and select Southeast Asian and European states.


The Indo-Pacific is a region where cooperation, conflict, and competition are intertwined. Given the conditions and constraints Japan faces, the future of the nation’s security pivots on practicing constructive diplomacy to work with the regional stakeholders, while sharpening defense readiness to deter and defend against threats. For decades, Japan has averted from adopting robust military measures due to domestic and international constraints and implications. However, current threats have reached the point where they overwhelm the capacity and policies to date, therefore requiring more precise and robust defense and deterrence measures, alongside diplomatic work vis-à-vis regional stakeholders.

The question, however, lies in the recipe that balances defense and diplomacy. The future of Japan’s national security will not be simply determined by rendering the visions and devoting resources, but also enacting the right policies and setting the right frameworks. To achieve this, Japan will need to re-evaluate the precedentism and old politics that have constrained its development. Instead, it will need to take on more innovative measures by exploiting various options and measures to attain abilities that contribute to both national security and a stable and harmonious Indo-Pacific.


Ryo Hinata-Yamaguchi is a Project Assistant Professor at the Research Center for Advanced Science and Technology at the University of Tokyo and also an Adjunct Fellow at the Pacific Forum. He has presented, published, and consulted on a variety of topics relating to defense, security, and transport governance in the Indo-Pacific. Ryo previously served as a Non-Commissioned Officer in the Japan Ground Self-Defense Force (reserve) and has also held positions at the Pusan National University, Universitas Muhammadiyah Malang, FM Bird Entertainment Agency, International Crisis Group Seoul Office, Sasakawa Peace Foundation, Embassy of Japan in Australia, and the Japan Foundation Sydney Language Centre. Ryo received his PhD from the University of New South Wales, MA in Strategic and Defense Studies and BA in Security Analysis from the Australian National University, and was also a Korea Foundation Language Training Fellow. He can be followed on Twitter at: @tigerrhy.


[1] Matthew M. Burke and Mari Higa, “Japan scrambled more fighters to intercept Chinese aircraft over the summer,” Stars and Stripes, 20 October 2021,

[2] “North Korea fires suspected submarine-launched missile into waters off Japan”,, 19 October 2021,

[3] AP in Moscow, “Russia sends Defence Missiles to Pacific Islands Claimed by Japan,” The Guardian, 2 December 2021,

[4] See: Maria Siow, “South China Sea: will Aukus affect Asean’s code of conduct talks with Beijing?,” South China Morning Post, 21 November 2021.

[5] See: Ryo Hinata-Yamaguchi, Defense Planning and Readiness of North Korea: Armed to Rule Oxfordshire, UK and New York, NY: Routledge, 2021.

[6] Missile Defense Project, “Missiles of North Korea,” Missile Defense Project, 14 June 2021.

[7] Ministry of Foreign Affairs of Japan, “Northern Territories Issue,” 1 March 2011.

[8] Yu Koizumi, “Russian Military Modernization in the Northern Territories and Its Implications for Japanese Foreign Policy,” Sasakawa Peace Foundation International Information Network Analysis, 31 May 2021.

[9] Jesse Johnson, “Chinese and Russian navies' Tsugaru Strait transit highlights growing defense ties,” Japan Times, 19 October 2021,

[10] Japan Ministry of Defense, Defense of Japan 2020, Tokyo, Japan, 2020, p. 200.

[11] Ministry of Foreign Affairs of Japan, “Japan’s Security Policy,” 12 April 2016.

[12] See: Jeffrey W. Hornung and Mike M. Mochizuki, “Japan: Still an Exceptional U.S. Ally,” The Washington Quarterly 39, no. 1, 2016.

[13] Japan Ministry of Defense, National Defense Program Guidelines for FY 2019 and Beyond, 18 December 2018, p.11.

[14] See: Japan Ministry of Defense, Defense Programs and Budget of Japan - Overview of FY2022 Budget (Draft), Tokyo, Japan, 2021; Diego Lopes da Silva, Nan Tian, and Alexandra Marksteiner, “Trends in Military Expenditure, 2020,” in SIPRI Fact Sheet, April 2021.

[15] See: Pam Kennedy, “How Japan’s Aging Population Impacts National Defense,” The Diplomat, 28 June 2017.; Tom Phuong Le, “Tokyo Wants to Upgrade Japan’s Defense Capacity. A Demographic Crisis Could Get in the Way,” The Washington Post, 30 July 2021.

[16] Japan Ministry of Defense, “Defense Programs and Budget of Japan - Overview of FY2021 Budget,” Tokyo, Japan, 2021, p.47.

[17] See: Masashi Murano, “The Modality of Japan’s Long-Range Strike Options,” in: Jonathan D. Caverley and Peter Dombrowski (eds.), Policy Roundtable: The Future of Japanese Security and Defense, Texas National Security Review, 1 October 2020.

[18] See: Ryo Hinata-Yamaguchi, “Japan’s Defense Readiness: Prospects and Issues in Operationalizing Air and Maritime Supremacy,” Naval War College Review, Summer 2018.

[19] See: Japan Ministry of Defense, “Defense Programs and Budget of Japan - Overview of FY2021 Budget.”; ibid, “Defense Programs and Budget of Japan - Overview of FY2022 Budget (Draft).”

[20] See: Richard L. Armitage and Joseph S. Nye, “The U.S.-Japan Alliance: An Equal Alliance with a Global Agenda,” Washington, DC: CSIS, 2020.

[21] See: Tate Nurkin and Ryo Hinata-Yamaguchi, “Emerging Defense Technologies in the Indo-Pacific and the Future of US-Japan Cooperation,” Report, Atlantic Council, Washington, DC, April 2020.


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