Inside the “Puzzle Box”: Unlocking Domestic Barriers to Japan’s Defence Transformation

CSDS POLICY BRIEF • 19/2025

By Eva Pejsova

15.7.2025

Key issues

• Japan’s defence modernisation is hindered by legal limits, institutional rigidity and siloed systems, affecting cooperation and crisis readiness;
• A whole-of-society approach with stronger inter-agency and public-private coordination is vital to close gaps in emergency planning and response;
• Early planning, refined command structure and public debate are key to Japan’s goal of becoming a fully-fledged security actor.

Introduction

Japan has emerged as a key player and partner for ensuring peace and security in the Indo-Pacific. Nested in an increasingly hostile and contested neighbourhood, Tokyo has embarked on an impressive build-up of its security and defence posture over the last decade, vowing to play a more proactive role in regional affairs. As a central pillar of the United States (US)-led security architecture, Japan is at the heart of the expanding network of minilateral security arrangements, including the Quadrilateral Security Partnership (QUAD), the SQUAD or the US-Republic of Korea-Japan trilateral cooperation. Outside the US-Japan Alliance, Japan has also deepened bilateral security partnerships with Australia, France, Germany, Italy, the Philippines, the United Kingdom (UK), as well as the European Union (EU) and NATO. As outlined during the US Defence Secretary Pete Hegseth’s visit to the region in March 2025, “warrior Japan”  is expected to be at the forefront in deterring Chinese military aggression in East Asia, including across the Taiwan Strait.

To be sure, the level of expectations facing Japan is high and likely to grow in the future. The central question remains: is Japan ready? How prepared is it to defend itself, and how capable is it to support the US or other partners in case of a major regional crisis? When addressing this question, the bulk of analysis focuses on the hardware – its defence capabilities, defence industrial and technological base and other strategic enablers necessary for enhancing its operational readiness. Another set of constraints refers to the country’s stagnating economy, including budgetary constraints, unpopular defence tax hikes and monetary weakness. Indeed, the recent cancellation of the “2+2” meeting with the US over Washington’s demands to move to 3.5% or even 5% Gross Domestic Product in defence spending only attests to how sensitive the financial side of Japan’s defence build-up is. Finally, a common concern is Japan’s society and changing demography, entailing personnel shortages and difficulties in recruiting for the Japan Self-Defence Forces (JSDF), as well as a general lukewarm public support for defence reforms.

On the rather long list of hurdles, however, one aspect remains often overlooked: Japan’s complex legal and institutional landscape. This CSDS Policy Brief sheds light on some of the lesser-known facets of Japan’s national security apparatus, pointing out legal and institutional challenges that have a direct impact on its defence and cooperation with external parties. Starting with the broader picture, it first focuses on information and cybersecurity, cited as major weaknesses (not only) in the US-Japan alliance, as well as on Japan’s strict nuclear safety regulations, which limit its ability to host nuclear-powered vessels. Second, it looks at Japan’s preparedness and readiness in times of crisis, zooming in on complexities in the US-Japan Control and Command (C2) structure, but also in domestic emergency planning. Finally, it pinpoints some of the limitations in countering grey zone challenges, including China’s hybrid maritime activities, disinformation and economic security, which are high on the agenda for cooperation with Europe. Overall, the Policy Brief argues that among the many obstacles on the path of Japan’s security and defence transformation, addressing legal and institutional barriers may be one of the least problematic, yet crucial parts of the puzzle, helping it to unlock its full potential as a security actor.

The devil is in the detail 

Information and cybersecurity are at the core of deepening security and defence ties. With the US and other international partners, Japan has been eager to explore new areas of military cooperation, including joint defence industrial production and technology development. However, its ability to protect sensitive information and data has been repeatedly put in question. Like many countries, Japan has been a victim of cyberattacks. The 2011 attack on Mitsubishi Heavy Industries (MHI) targeting shipyards building destroyers and submarines, as well as its production plant of rockets and missiles, was a first wake-up call. The revelation of infiltration of China-backed hacking groups into Japan’s defence network between 2019-2024, with over 200 attacks on the Ministries of Defence and Foreign Affairs and the Japan Aerospace Exploration Agency (JAXA), to gather information on the US-Japan alliance and other sensitive topics sounded a loud alarm, putting information-sharing between the two allies at risk. To date, Japan still needs to fully develop proactive surveillance, reconnaissance and attribution capabilities in cyberspace. A unified framework for information-sharing with private infrastructure operators remains subject to future discussion, and improvements need to be made to effectively track, trace and respond to such activities.

The importance of information sharing for deepening defence partnerships is beyond question. Timely and accurate intelligence sharing is critical to anticipate, prepare for and respond to possible crises, but also a much-needed tool for fostering trust and enhancing interoperability between partners. The debate about Japan’s participation in key intelligence sharing frameworks, such as the “Five Eyes” initiative, has been a long one, put forward by former Defence Minister Taro Kono already in 2020. Indeed, as a key US ally with closely aligned strategic objectives and established intelligence-sharing agreements with Australia, Canada and the UK, Japan would be a most logical and valuable “sixth eye” in the grouping. However, the partnership’s high standards on information protection and intelligence capabilities prevent its accession. The lingering debate about Japan joining AUKUS’ Pillar II, which would enable it to take part in sharing advanced military technologies, echoes the same problem and is directly linked to Tokyo’s absence from the “Five Eyes” grouping itself.

A major stumbling block is the lack of an integrated intelligence structure in Japan. Several intelligence agencies are in charge of intelligence collection, including the Cabinet Intelligence and Research Office (CIRO), the Public Security Intelligence Agency, the Defence Intelligence Headquarters and the National Police Agency. However, there is no centralised assessment body to integrate and analyse their findings, comparable to the US’ Office of the Director of National Intelligence or the UK’s Joint Intelligence Organisation, that could serve as a main counterpart in intelligence cooperation. Japan is also an exception among advanced countries in not having a comprehensive anti-espionage law, which would allow it to penalise and effectively counter foreign espionage activities. Postwar emphasis on freedom of expression and the right to know, as well as historical aversion to prewar public security laws, have hindered the implementation of adequate legislation, showing a discrepancy between national security needs and the criminal justice system.

While Japan’s 2022 National Security Strategy (NSS) urges the government and the private sector to ‘work on information security to prevent leakage of critical information on national security’, it contains no concrete reference to implementing intelligence reforms. It was only in May 2025 that Sanae Takaichi, the Chair of the Liberal Democratic Party (LDP) Committee on Public Security and Counterterrorism, and former Economic Security Minister, submitted a proposal for an anti-espionage law. Whether this will lead to legislation remains uncertain, as it would require not only political will but also the necessary public awareness of the issue. Moreover, the proposal itself carries no binding force. On the cybersecurity front, a new Cybersecurity Response Capability Enhancement Act was passed in May 2025, enabling the police and JSDF to monitor and analyse communications data during peacetime and to penetrate and neutralise the sources of cyberattacks, as well as to strengthen the Cybersecurity Strategic Headquarters by establishing a new senior position of a Cabinet Cybersecurity Officer. However, its successful implementation will depend on securing sufficient personnel and convincing the private sector to get fully on board.

Finally, an important hindrance to Japan’s capacity as a defence partner is its strict regulation of nuclear safety and its “Three Nuclear Principles”. Reputed for its high environmental standards and cautiousness in handling radioactive material, especially after the Fukushima Daiichi nuclear plant disaster, the Nuclear Regulation Authority (NRA) applies strict safety protocols and transparency procedures, which make the stationing of any foreign nuclear-powered vessels and nuclear weapons on its soil virtually impossible. This explains why the French nuclear-powered aircraft carrier Charles de Gaulle, which concluded its major deployment in the Indo-Pacific in April 2025, did not make a port call in Japan. The issue is also part of ongoing negotiations of the Reciprocal Access Agreement (RAA) with France, expected to be concluded by the end of 2025. British nuclear submarines face the same problem, as well as any country other than the US, including Australia’s future SSNs developed under the AUKUS framework, which are planned to be deployed by 2030. Needless to say, complex regulatory procedures may entail significant operational constraints in times of crisis, slowing down deployments and the resupply of nuclear-powered vessels of allied forces. Although safety regulations are reassuring internationally and for its home audience, the heightened climate of tensions means that exceptional emergency measures deserve to be part of a broader debate.

Readiness in times of crisis? 

To be sure, Japan will be on the frontline of any possible contingency in East Asia. The risk of a major crisis across the Taiwan Strait or on the Korean Peninsula has reignited the debate about asymmetries within US-Japan burden-sharing, raising questions about operational control, command, communications and logistics. The recent decision to upgrade US Forces Japan (USFJ) from an administrative authority to a joint operational headquarters in March 2025, to serve as a counterpart of the JSDF’s Joint Operations Command, reflects the need to deepen interoperability. However, it says little about the exact C2 relationship both within other US services in the region (i.e. INDOPACOM, the 7^th Fleet, etc.) and with Japan itself, in times of crisis. A particular challenge is how to coordinate Japan’s counterstrike capabilities. Tokyo made clear that the JSDF would always maintain an independent chain of command under the civilian authority of the Prime Minister and never be subordinated to the US military. That said, keeping strictly parallel C2 structures may be difficult in situations requiring real-time coordination, such as joint targeting and strikes. The “prior consultation” mechanism under the US-Japan Security Treaty serves as a legal basis for US military actions involving Japan. However, concerns arise over how quickly such consultations can be conducted and how their outcomes would affect the operational decisions of the JSDF. In scenarios that do not involve a direct attack on Japanese soil, C2 arrangements for JSDF when supporting US military operations are even more ambiguous. In sum, much work still needs to be done to modernise and fine-tune bilateral operational agreements for effective decision-making in case of emergencies, which should ideally be accompanied by an adequate public debate.

As part of a Taiwan contingency planning, Japan has been actively developing strategies for the evacuation of citizens from its Southwestern (Nansei) Islands. Since 2016, the Japan Ground Self-Defence Force (JGSDF) has expanded its presence and installed garrisons and missile defence systems on Miyako, Ishigaki and Yonaguni islands. Japan and US forces held their first large-scale evacuation drill simulating a Taiwan emergency in October 2024. At the national level, the government unveiled a comprehensive plan for the evacuation of up to 120,000 civilians from the Sakishima Islands under the Civil Protection Law in late March 2025 and announced further evacuation drills in 2026. However, the success of such an operation heavily relies on the participation of local governments, which need to provide shelters, food, medical supplies and facilitate evacuation routes. Some of them, especially the Okinawa Prefecture, which hosts 70% of US military facilities, have been reputed for their strong anti-American sentiments and have shown little alertness and enthusiasm for emergency planning.

While the Taiwan contingency is certainly an acute challenge, it is only one of many emergencies that Japan needs to prepare for. North Korea’s ballistic missiles and nuclear programme are a persistent threat that requires a more robust, permanent and tightly coordinated trilateral cooperation with the US and South Korea. In a country where natural disasters are commonplace, the risk of having to handle several crises simultaneously, cyberattacks, pandemics and military crises, cannot be excluded. Japan’s emergency preparedness and response have been tested on multiple occasions. Although reputed for its attention to detail and organisational effectiveness, a closer look reveals a siloed approach and a lack of inter-agency coordination. The Cabinet Office’s Disaster Management Division is responsible for basic functions related to disaster prevention, response and recovery. However, the actual implementation of disaster measures during emergencies, as well as within individual administrative sectors, is carried out by the respective ministries and agencies, in accordance with their jurisdiction. Preparations are currently underway for the launch of a Disaster Management Agency in Financial Year 2026. Whether or not it will manage to provide an “all-hazard” response mechanism remains to be seen.

It is noteworthy that the Japanese Constitution does not contain an emergency clause, which would allow it to shift or accelerate legal procedures in times of crisis. The debate on introducing such a clause has reemerged in the context of the COVID-19 pandemic, but opponents have raised concerns over the risk of abuse of power, arguing that targeted legislative measures will achieve better results. In the meantime, boosting the capacity to effectively manage complex overlapping crises would require Japan to revise its legal and institutional crisis management mechanisms, clarify inter-agency coordination protocols and ideally establish an integrated emergency response authority under the Prime Minister’s office.

Countering hybrid challenges 

Short of an open conflict, Japan faces a multitude of hybrid threats daily. China’s grey zone activities in the East China Sea have been among the most concerning ones, multiplied since Japan’s nationalisation of the disputed Senkaku/ Diaoyu Islands in 2012. Since passing the Coast Guard Law in 2021, Japanese fishing boats have been regularly exposed to harassment by Chinese white hauls. Reports of Chinese marine research vessels engaging in suspicious activities such as maritime surveillance, seabed surveys or installation of structures within Japan’s Exclusive Economic Zone (EEZ) and territorial waters have also multiplied. Like most countries, Japan maintains a strict distinction between the roles of the civilian coast guard (JCG) and the JSDF, which limits its operational leverage in the face of such grey zone challenges. The need to improve coordination between the JCG and the Japan Maritime Self-Defence Force has been discussed since 2014, with the JCG significantly expanding and modernising its capabilities since 2022 under the “maritime security capability enhancement” measure. The 2023 “Control Guidelines” for coast guards finally designate specific missions for both players: while the JCG primarily focuses on law enforcement, in case of an escalation of tensions, it will be placed under the control of the Ministry of Defence to enable joint command with the JSDF. Nevertheless, challenges remain, notably in ensuring the safety of the JCG when conducting operations. So far, it is unclear which maritime areas and missions the JCG would be responsible for and what the operational rules would be under such a unified command.

A second major grey zone challenge is disinformation, or in the EU’s parlance: Foreign Information Manipulation and Interference (FIMI). The greatest wake-up call was the “Fukushima scandal” – a widespread fake news campaign around the released wastewater from the destroyed Fukushima power plant in summer 2023. A video originally posted on Chinese social media showing tons of dead fish and polluted water quickly spread across East Asia and beyond, triggering anti-Japanese sentiments and boycotts of Japanese seafood. In response, the Japanese government doubled down on countering disinformation with international partners, especially with the G7 countries, NATO and the EU. An effective national response system, however, remains to be developed. The National Center of Incident Readiness and Strategy for Cybersecurity (NISC) and the National Security Secretariat (NSS) face limitations in terms of personnel, organisational structure and technical capacity to collect and analyse information circulating on social media and online platforms. Disinformation countermeasures are fragmented across ministries: the Ministry of Defence for security issues, the Ministry of Internal Affairs and Communications for election-related concerns and the Ministry of Foreign Affairs for diplomatic matters – resulting in the absence of a centralised authority to oversee and coordinate a unified national response.

Finally, although Japan is often considered a frontrunner in the economic security domain, the institutional foundations still need to be developed. The 2022 Economic Security Promotion Act is indeed a comprehensive piece of legislation that provides for the strengthening of supply chains for critical goods and the introduction of a prior review system for core infrastructure. The 2024 Security Clearance Act imposes eligibility assessments for government officials and private-sector employees to access information about critical infrastructure and supply chains. Effective public-private cooperation is key here. In general, Japan’s businesses tend to view security risks as external and distant issues and they often exhibit a passive attitude toward risk awareness and institutional cooperation. According to a recent survey by the Institute of Geoeconomics, while 70% of Japanese companies acknowledge ‘uncertainty over US-China relations’, less than 20% feel any actual impact, and less than 30% have taken any concrete measures or consider transferring production bases from China. At the same time, all expect the government to provide clear guidance on economic security while promoting corporate interests.

The way forward: breaking silos, building capacity

Overall, most cases analysed in this Policy Brief point to similar patterns, which can be grouped into four main problems. First, they highlight an issue of coordination. Whether in information security, cybersecurity, emergency planning or countering disinformation, a fragmented institutional architecture and issue-specific institutional mandates result in a siloed approach, which complicates the implementation of national guidelines. An establishment of centralised inter-agency coordination mechanisms with strong command authority directly under the Prime Minister’s office could be a partial remedy, provided that all agencies and actors share the same understanding and the sense of urgency about national security concerns.

The second issue, closely related to the first one, is insufficient public awareness and a lack of coordination with the private sector. According to the public opinion survey by Tokyo University’s ROLES think tank in March 2025, 65% of respondents are concerned about Japan’s security, but only 40% favour greater military spending and nearly 50% oppose the use of force under any circumstances. Effective emergency planning, economic intelligence and countering disinformation and cybercrime need a whole-of-society approach. To get the private sector, academic institutions and local governments fully on board, there is a need to double down on strategic communications, with adequate media campaigns and educational programmes. Building a defence posture that resonates with the public requires that individuals confront real-world risks, engage in dialogue with political leaders and participate in fora that enable collective reflection and discussion.

Third, the workforce gap is a recurring problem. The difficulty of the JSDF in recruiting personnel has been widely reported, especially in the rank-and-file category. For most of the critical domains discussed here, such as cyberdefence, intelligence gathering, disinformation or emergency response, Japan will need high-skilled talent that is not only aware of national and international security concerns, but also excels in new technologies, and is proficient in foreign languages. In cybersecurity, the Ministry of Defence plans to recruit 20,000 personnel by 2027. To attract such talent, the government needs to provide incentives to counterbalance the highly competitive private sector opportunities, notably by matching salaries and overall working conditions, as well as by building career paths focused on developing specialists rather than relying on the traditional generalist model.

Finally, perhaps the most important factor is early planning. Finetuning the design, logistics and clear operational C2 structures with the US, as well as within internal governmental agencies and local governments, is critical to Japan’s operational readiness. The question of nuclear safety standards also deserves a broader public debate. Given the lengthy process this may require, it is necessary to start now. The good news is that most of these adjustments are doable, provided there is sufficient political will. By advancing on the internal debate and addressing some of the pending legal and institutional barriers, Japan will be one step closer to achieving its main long-term strategic objective: becoming the security actor it needs to be, and one that its allies and partners would benefit from.

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