Introduction

The establishment of Japan’s Official Security Assistance (OSA) framework is a vital step in Japan’s post-war defence and security posture. It demonstrates an evolution of strategic thinking in Tokyo that has sought to recalibrate Japan’s security role amid intensifying regional threats, particularly from China, Russia, and North Korea, as well as rising expectations from the United States (US). China’s maritime assertions in the East China Sea, Russia’s militarisation of the Kuril island chain, four of which^[a] Japan identifies as its Northern Territories,^[1] and North Korea’s missile and nuclear provocations have eroded the buffer of predictability that Tokyo once relied on. At the same time, Washington, particularly under Trump 2.0, expects allies^[2] to shoulder more of the defence burden, modernise capabilities, and deepen interoperability, alongside multilateral coordination in the Indo-Pacific.

The OSA framework enables Japan to provide defence equipment and technology to like-minded militaries following the rules-based international order in the Indo-Pacific and beyond. It is Tokyo’s first overt step in the realm of military assistance since the Second World War and presents a shift toward active participation in regional security, emphasising deterrence through partnerships.

OSA: Objectives, Scope, and Instruments

A number of key developments led to the establishment of the OSA. Central among these was Japan’s revision of its three key national security documents in December 2022—the National Security Strategy (NSS),^[3] National Defence Strategy (NDS),^[4] and Defence Buildup Program.^[5] With these documents, Tokyo emphasised the need for counterstrike capabilities and broader defence cooperation with partners. The NDS underscored Japan’s intention to “fundamentally reinforce its defence capabilities”^[6] and recognised that security assistance was vital for shaping a desirable security environment in the Indo-Pacific.

In 2022, Japan acknowledged China as a vital strategic challenge, consistent with its framing of the nation as a pressing security concern,^[7] a stance cemented over the past decade owing to multiple factors. Indeed, as early as the 2011 Defence White Paper, Tokyo expressed unease about the rapid modernisation of China’s military and its growing maritime activity.^[8] The 2012 Defence White Paper adopted an even sharper tone toward China, particularly in characterising Beijing’s behaviour around the Senkaku Islands. Building on the language shift first seen in 2011, the document again employed the term kouatsuteki (“pressing from a superior position”) to describe Chinese maritime activities in the South China Sea. While the English version softened this to “assertive”, the Japanese term carries a stronger connotation—implying pressure exerted from a position of superiority. This choice of wording marked a notable departure from earlier white papers.^[9] By 2019, Japan’s annual security documentation had evolved markedly. The Defence White Paper and Diplomatic Bluebook from this year onward articulate far more pointed concerns: China is no longer merely a “potential risk”, but is effectively portrayed as a systemic challenge to Japan’s national security.^[10]

Tokyo increasingly emphasises threats related to China’s maritime assertiveness, targeting of disputed islands, and opacity in military affairs. Furthermore, Japan’s deepening strategic anxiety has been perceptible in subsequent years as it highlighted the growing closeness between China and Russia, particularly in joint naval operations, and underscored the destabilising potential of North Korea’s missile and nuclear programmes.  These developments have framed China not just as a regional competitor, but as the “greatest strategic challenge” confronting the world,^[11] and thereby prompting Japan to recalibrate its defence posture accordingly.

Figure 1: Japan’s Security Environment

Source: Defence of Japan, 2025.^[12]

It is noteworthy that Japan has actively supported ASEAN (Association of Southeast Asian Nations) nations’ maritime capacity building, providing patrol boats to Indonesia, advanced equipment to the Philippines, and coast guard training programmes over the past decade. The Abe administration pledged six modified vessels to Vietnam and ten new patrol boats to the Philippines.^[13] Indeed, Abe’s Indo-Pacific vision consistently foregrounded ASEAN as central to Japan’s regional strategy. In a 2013 trip to Southeast Asia—his very first overseas visit included Vietnam, Thailand, and Indonesia—Abe highlighted that “relations with ASEAN…form ‘a supremely vital linchpin’ for Japan’s diplomatic strategy.”^[14] He emphasised that free seas governed by rules, not force,^[15] are the foundation of shared prosperity with ASEAN. Abe’s Project Syndicate piece, ‘Asia’s Democratic Security Diamond’, published in 2012,^[16] linked Japan-ASEAN cooperation to a broader maritime security architecture, anchoring the importance of ASEAN amid rising Chinese assertiveness in the South China Sea.

Table 1: Japan’s Support for ASEAN Maritime Capacity Building

ASEAN Country/ASEAN-wide	Type of Support/Activity	Details
ASEAN-wide	Japan–ASEAN Ship Rider Cooperation Program	Includes cooperation between ASEAN, Japan and Pacific Island countries through the Ship Rider Cooperation Program as part of the JASMINE (Japan-ASEAN Ministerial Initiative for Enhanced Defence Cooperation) initiative.
ASEAN-wide	Defence cooperation	Specific defence cooperation that Japan would like to pursue together with ASEAN to realize the shared vision of the future for the Indo-Pacific region
ASEAN-wide	Across services (MSDF, GJSDF, MSDF, etc.)	Includes support for capacity building, cooperation in Humanitarian Assistance/Disaster Relief (HA/DR), defence equipment and technology cooperation and others. WPS (Women, Peace, and Security); many of these involve maritime security and operational capacity.
ASEAN-wide	ASEAN Defence Ministers’ Meeting-Plus (ADMM-Plus)	Japan co-chairs the Maritime Security Experts’ Working Group established under the framework of the ADMM-Plus, conducting workshops, joint exercises, and training. Japan and the Philippines are co-chairing the 5th cycle of the Maritime Security Expert Working Group (2024–2027).
ASEAN-wide	Cyber capacity-building for ASEAN	JSDF personnel serve as instructors for cybersecurity personnel in ASEAN countries, enabling them to respond more appropriately to cyberspace incidents.
ASEAN (general)	ADI (ASEAN Direct Communications Infrastructure (ADI) hotline	Japan became the first Plus Country to operationalise ASEAN's defence hotline, improving crisis communication, including maritime incidents.
Indonesia	Maritime surveillance capacity enhancement	Agreement to improve capacity in maritime surveillance and maritime law enforcement, including fishery surveillance vessels. (To strengthen cooperation in the region around the Sulu and Celebes Seas)
Indonesia	OSA-funded high-speed patrol boats (2025)	Under OSA, Japan is to provide high-speed patrol boats to strengthen Indonesian maritime enforcement capacity.
Philippines	HA/DR capacity building (maritime relevance)	The JSDF (Japan Self-Defense Forces) provided HA/DR capacity building for the Philippines (ships, response operations).
Philippines	Transfer of maritime surveillance radars	Japan transferred four air-surveillance radar systems (operational support included) to strengthen the Philippines' situational awareness.
Vietnam	Underwater UXO clearance training	Underwater EOD training contributes to safer maritime operations.
Vietnam	Air rescue maritime-adjacent capacity	Air rescue training provided.
Malaysia	HA/DR capacity building (maritime relevance)	Training in HA/DR relevant to coastal disaster response.
Thailand	Transfer of defence technology (potential maritime)	The agreement enables maritime-related equipment transfer.
Myanmar / Brunei	Maritime security capacity building	Listed as recipients of Japan's maritime security capacity-building programmes.
Singapore	Transfer agreement supporting maritime security	Defence technology transfer agreement enabling maritime-related cooperation.
Timor-Leste (newest member)	Maritime Law Enforcement Capacity Building	JSDF and US Armed Forces together with Australia and New Zealand  conduct the ‘Hari’i Hamutuk’ [b] capacity-building exercise for Timor-Leste, organised by the Australian Defence Forces (ADF), for technical guidelines.

Source: ‘Defence of Japan 2025’.^[17]

With relaxed arms export rules and revised ODA guidelines, Japan can expand its efforts in the South China Sea. Potential measures include transferring used Japan Coast Guard and Maritime Self-Defence Force (SDF) equipment, such as aircraft and support ships, to partners like Singapore and Indonesia. Additionally, Japan could establish training, maintenance facilities, and deploy personnel for operational support.^[18]

The OSA framework allows Japan to deliver a broad range of military assistance, including defence hardware, technology, and dual-use infrastructure. This is particularly important in a region where maritime security cooperation is increasingly becoming crucial to ensuring freedom of navigation in contested waters, with Japan’s membership in UNCLOS (United Nations Convention on the Law of the Sea) bolstering its advocacy for legal norms.^[19]

In the Philippines, for instance (one of the first recipients), the utility of OSA—given its strategic location near the South China Sea and strengthened defence ties with Japan and American collaborative efforts, such as the Japan-Philippines Terms of Reference (TOR) for disaster response and trilateral^[c] defence cooperation—demonstrate the OSA's potential to enhance vigilance, disaster readiness, and interoperability among forces.^[20] These systems aim to strengthen the capacity of the Armed Forces of the Philippines to monitor critical sea lanes like the Luzon Strait that are crucial for global trade and regional security​. Enhancing Manila’s military capabilities, such as through the provision of radar systems, is expected to improve its maritime domain awareness and bolster regional deterrence. This directly serves the strategic interests of both Japan and the US. For Tokyo, a more capable Philippines strengthens the frontline of maritime monitoring in waters that connect the Western Pacific to the South China Sea. Better detection, tracking, and reporting by the Philippines would reduce the operational pressure on the Japan Self-Defence Forces, help identify grey-zone coercion earlier, and contribute to a more integrated regional picture of Chinese naval and coast guard movements.

For the US, enhanced Philippine capabilities fill a long-standing gap in the alliance architecture. Greater Philippine situational awareness enables more effective coordination with American forces under the EDCA framework,^[21] improving cueing and intelligence sharing. Ultimately, Philippine capacity-building multiplies deterrence and supports networked regional security.

This dual-use approach balances developmental and strategic needs, making aid more palatable in recipient countries. Importantly, these provisions adhere to Japan’s ‘Three Principles on Transfer of Defence Equipment and Technology’,^[22] ensuring that assistance is transparent and in accordance with international norms​. This scope also allows Japan to address immediate security concerns while building long-term defence capabilities among partners.

Strategically, a key objective of OSA is to deepen Japan’s alliances and partnerships in the Indo-Pacific. This focus aligns with Japan’s broader geopolitical objectives under its Free and Open Indo-Pacific (FOIP) vision.​ The framework strengthens bilateral relationships while contributing to larger regional coalitions like the Quad. It also reflects Japan’s broader effort to offset Chinese and Russian influence, particularly in developing nations susceptible to external pressure. By combining military aid with economic initiatives, Japan positions itself as a comprehensive security partner.

There are also potential broader objectives behind the implementation of OSA. For years, Tokyo has sought to export military equipment to countries,  including amphibious aircraft to India,^[d] but Japanese companies have yet to secure any major deals. Following revisions to the Three Principles on Transfer of Defence Equipment and Technology,^[23] Japan is now in a better position to export finished defence products under certain conditions paving the way for future exports of jointly developed fighter jets to countries with defence equipment agreements. Most notably, Japan secured a landmark US$6.5-billion contract to build next-generation Mogami-class warships for Australia, marking one of its largest defence exports since ending its post-war arms ban and a breakthrough for Japanese defence suppliers.^[24] Assessments suggest that the experience and insights gained from OSA could serve as a foundation for designing larger-scale defence equipment transfer programmes. These could potentially employ financing models similar to those Japan has used for large infrastructure projects, like the bullet train initiative in India.^[25]

The strategic utilisation of OSA requires a comprehensive framework, involving close coordination among Japan’s ministries, the Self-Defence Forces, and partner countries. Priorities include building trust through joint capacity-building initiatives, leveraging OSA to achieve policy objectives such as intelligence sharing and strengthening partnerships, and integrating OSA with complementary tools. By developing sustainable defence relationships and enhancing regional access, the OSA can contribute to Japan’s broader Indo-Pacific strategy and the collective deterrence framework in the South China Sea.^[26]

The framework is emblematic of Tokyo’s wider effort to normalise defence cooperation and signal strategic resolve in a more contested Indo-Pacific. Indeed, China’s growing maritime assertiveness, particularly in the East and South China Seas, has prompted Tokyo to respond proactively by strengthening regional deterrence through strategic partnerships. The OSA was thus devised not only as a tool of defence diplomacy but also as a mechanism for capacity-building among Southeast Asian countries facing pressure from Beijing. In April 2023, Japan announced its first four OSA partners^[27]—the Philippines, Malaysia, Bangladesh, and Fiji—reflecting a focus on countries critical to Indo-Pacific maritime security. Thailand, Sri Lanka, Tonga, East Timor and Papua New Guinea are set to become the newest recipients in 2025. Despite a modest initial budget of ¥2 billion (FY2023), Japan plans to scale up funding and implement equipment transfer projects tailored to the needs of its partners, including telecommunications gear and heavy machinery. Larger and more advanced equipment transfers, like air surveillance radars, may require innovative funding mechanisms like export loans through JBIC (Japan Bank for International Cooperation) or purchase subsidies.^[28] Indeed, the inclusion of new recipient countries comes in the wake of the government approving a 60-percent hike for OSA spending for the third time since it was launched.^[29]

In essence, the OSA represents the institutionalisation of Japan’s evolving security engagements, reflecting a convergence of domestic policy reforms, constitutional reinterpretations, and external pressures, especially the intensifying US-China rivalry and the need to support a free and open Indo-Pacific. While modest in scale, its strategic implications for regional security dynamics are significant.

ODA vs OSA

The provision of military aid through the OSA represents a departure from the traditional Official Development Assistance (ODA) model, which explicitly prohibited the use of aid for military purposes under Japan’s ‘Three Principles on Arms Exports’.^[30] However, Tokyo had already begun revising these restrictions incrementally over the years. In 2014, the Abe government reinterpreted Japan’s pacifist Constitution to allow for collective self-defence,^[31] and revised the arms export principles to permit the transfer of defence equipment for peaceful and cooperative purposes. This paved the way for initiatives like the Defence Equipment and Technology Transfer Agreement, signed with various partners including the Philippines, India, and Malaysia.

The 2015 Development Cooperation Charter opened the door to limited ODA support for armed forces for non-military purposes, such as disaster relief. For instance, lifesaving equipment was provided to the Philippine Armed Forces in 2021, marking a precedent for Japan’s aid linking with security objectives. While this reflects Japan’s intent to address geopolitical concerns, it has sounded the alarm about the militarisation of development aid, public unease, and potential disinformation risks.^[32] Therefore, the ODA policy is also being reassessed alongside revisions to its NSS and Development Cooperation Charter, reflecting the evolving global challenges posed by the COVID-19 pandemic, the war in Ukraine, and growing security needs in the Indo-Pacific.

Japan’s policymakers also advocated expanding ODA to build dual-use infrastructure, enhance maritime security, and foster regional stability. The Quad’s US$50-billion Indo-Pacific infrastructure initiative^[33] and the Kishida Vision for Peace^[34] highlight such strategic goals. However, critics caution against overburdening ODA with military roles. Instead, they propose establishing non-ODA economic cooperation mechanisms to support defence diplomacy and military capacity-building, enabling quicker and more targeted results while preserving the ODA’s non-military ethos. As Tokyo revises its NSS and aid strategy, balancing national interests with developmental objectives and maintaining international credibility will be crucial. A separate framework for security-focused economic cooperation could allow Japan to align its development and security policies more effectively without compromising its principles.^[35]

This reassessment led to the development of the OSA framework, which complements the broader revisions in Japan's National Security Strategy (NSS) in December 2022, acknowledging the increasing need to counterbalance the challenges posed by China and North Korea. Unlike the traditional ODA, which focuses on non-military development, OSA explicitly provides military-related aid, such as defence equipment and infrastructure upgrades for security purposes. This initiative also ensures that Japan’s security contributions align with its commitment to maintaining a rules-based order in the region.

OSA Allocations and Recipients

The OSA has expanded rapidly since its launch in 2023. At the programme level, Tokyo moved from a small, pilot budget in FY2023 to materially larger allocations in FY2024 and FY2025—roughly US$13.8 million in 2023, US$34.6 million in 2024, and US$56 million budgeted for FY2025—reflecting both a greater number of recipients and larger per-project grants.^[36] Since its launch, the programme has focused on providing non-lethal maritime and security capacity-building support to key littoral and island states. By FY2025, the programme expanded to additional recipients, maintaining a focus on coastal surveillance, maritime domain awareness, and training.

Table 2: OSA Allocations and Recipients

Fiscal Year	Budget (US$)	Recipient Countries	Key Projects/Focus	Notes/Details
FY2023	13.8 million	Bangladesh, Fiji, Malaysia, and the Philippines	Coastal surveillance radars, maritime domain awareness (MDA) equipment, associated training, and infrastructure	The Philippines: the first tranche funded coastal radars (~¥600 million / PHP 235 million); all projects were non-lethal and focused on maritime security. Pilot budget, early targeted approach.
FY2024	34.6 million	Bangladesh, Fiji, Malaysia, and the Philippines	Additional maritime security equipment, training, and infrastructure	The Philippines: second tranche (~¥1.6 billion / PHP 611 million); exchange notes signed for multiple projects, ongoing bilateral pipeline. The increase in budget reflects larger per-project grants.
FY2025	56 million	The Philippines, Malaysia, Indonesia, Thailand, Papua New Guinea, Sri Lanka, Timor-Leste, and Tonga	Coastal radars, MDA systems, training, logistics/infrastructure support	Geographic expansion to Southeast Asia, the Pacific, and the Indian Ocean; non-lethal focus maintained. MOFA exchange notes include ¥500 million OSA for Sri Lanka (Sep 2025) and a project with Papua New Guinea.

Source: Author’s compilation^[38]

The Public Pulse

Japanese public opinion increasingly acknowledges a deteriorating security environment. In the FY2024 Domestic Public Opinion Survey on Japan’s Diplomacy, 81.5 percent of respondents^[39] agreed that the security environment around East Asia is becoming more severe. Nearly 60 percent^[40] view strengthening cooperation with the US and allies as an important way to prevent further decline, while almost half (47.4 percent) support reinforcing Japan’s own defence capabilities. Surveys also show that support for further enhancing Japan’s defence capacity remains strong. For instance, more than 60 percent of voters in an Asahi Shimbun survey in 2023^[41] approved bolstering defence capabilities, a trend that has persisted since Russia’s invasion of Ukraine. The University of Tokyo (UTokyo) ROLES Survey in 2024^[42] similarly found strong public concern over threats from China, North Korea, and Russia, and correspondingly, noticeable support for strengthening the Japan-US alliance and closer ties with other democracies (e.g., Taiwan, Australia, the United Kingdom, North Atlantic Treaty Organization).

Despite the heightened threat perception and support for stronger defence, there are constraints to public acceptance. The UTokyo ROLES Survey in 2025^[43] showed that 45 percent of respondents agreed with the statement, “Japan must not use force under any circumstances,” despite around 65 percent of respondents being concerned about Japan’s security—a finding broadly consistent with August 2024 levels. This suggests that threat perceptions, likely shaped by China’s military activity, North Korea, and regional instability—are now structural rather than episodic. Moreover, outright opposition to defence spending has declined marginally, suggesting softening resistance rather than a decisive shift. About 60 percent also oppose Japan developing its own nuclear weapons or allowing US nuclear weapons to be stationed on Japanese soil—showing resistance to more radical deviations from post-war norms.

Figure 3: Public Opinion on Security (2024 and 2025)

Source: UTokyo ROLES Survey^[44]

Similarly, in the FY2024 MOFA survey, while many respondents want enhanced security measures, only 47.4 percent prioritise reinforcing their country’s own defence capabilities as a method of preventing deterioration in the security environment, lagging behind cooperation with allies (57.4 percent) and diplomatic efforts (34.8 percent) in importance.^[45] The survey underscores a public increasingly aware of both opportunities and risks in its foreign relations, particularly vis‑à‑vis the US and China. Nearly 82 percent of respondents perceive East Asia’s security environment as worsening, with 57.4 percent supporting stronger cooperation with the US and allied countries, and 47.4 percent advocating reinforcement of Japan’s defence capabilities, indicating strong public backing for a proactive security posture.

Regarding China, 60.9 percent of respondents called for a firm stance against intrusions into Japanese territorial waters, highlighting ongoing maritime concerns. Overall, the findings reveal a public consensus on combining robust defence, multilateral cooperation, and selective diplomacy to safeguard Japan’s security and economic interests. Moreover, a Yomiuri Shimbun poll indicates that 63 percent of respondents oppose any tax increase to fund defence spending. Only 28 percent support such an initiative.^[46] Even among supporters of the ruling party, less than half favour raising taxes for defence.

Public opinion in Japan thus appears broadly favourable to enhancing security cooperation and strengthening defence capabilities, especially in light of perceived external threats. At the same time, the data reveals a disconnect between threat perception and policy comfort. Japanese public opinion recognises growing insecurity but remains cautious about militarisation and coercive responses. For policymakers, this implies that defence reforms and spending increases will need continued framing around deterrence, self-defence, and necessity, rather than power projection, if public support is to be sustained. This creates a cautiously supportive environment for policies like OSA, which signal proactive engagement. Support is tempered by deep-rooted pacifist norms, constitutional constraints, and cost sensitivity. At the same time, the majority do not support combat roles, and many prefer Japan’s role to be limited (e.g., humanitarian, logistical). This suggests that OSA’s non-lethal framing will help its public acceptability.

Given that the public is less enthusiastic about Japan moving into new realms of military engagement (e.g., using force or hosting foreign weapons), this could limit how far the OSA can expand in its scope (especially toward lethal assistance or more forward-leaning military support). Additionally, while cooperation with allies is highly regarded, the Japanese are cautious about incurring heavy financial burdens for defence, suggesting that any expansion of OSA or other security assistance will require political legitimacy and fiscal justification.

Challenges and Constraints

In its present format, the OSA faces challenges, including the lack of a system for transferring Japan's expensive defence equipment via loans or export subsidies, and the absence of an agency like JICA for overseeing and facilitating infrastructure projects. The limited budget for OSA also makes large equipment grants unlikely. While the implementation guidelines allow for flexible interpretation, this could enable the creative and strategic use of OSA, including providing aid to countries transitioning from developing status or with complex political situations. The guidelines also allow support for armed forces and related organisations, expanding the scope for cooperation, particularly with Pacific Island nations lacking military forces. The OSA may also strengthen ties with these states, including those recognising Taiwan.^[47]

While the OSA provides military equipment support, it is not intended to create asymmetric power dynamics, as the equipment offered is often already available on international markets and may not markedly enhance recipient countries’ deterrent capabilities. Japan’s approach is to boost the capabilities of partner countries through military assistance. In an already fragmented ASEAN, Tokyo is seeking to prevent further Chinese dominance in the bloc. Policy analysts see Japan’s growing security and economic outreach to ASEAN as part of a deliberate counterbalancing effort.^[48]

First, Tokyo increasingly frames its ASEAN engagement in normative and rules-based terms offering ASEAN a contrasting model anchored in multilateralism, sovereignty, and ASEAN centrality. Tokyo is committed to deepening defence cooperation in areas such as capacity-building, joint exercises, and technology, a clear nod to rising maritime tensions with China.^[49] Second, Japan is leveraging its economic statecraft to provide real alternatives to Chinese influence. It continues to be a source of infrastructure investment in Southeast Asia, promoting connectivity projects without the debt‑dependency risks associated with Beijing’s Belt and Road Initiative (BRI).^[50] Moreover, by advocating for ASEAN’s strategic autonomy, Japan positions itself as a more reliable, less coercive partner. Tokyo also seeks to contribute to regional stability by supporting ASEAN’s capacity to address challenges like climate change, transnational crime, and peacekeeping, thereby enhancing ASEAN’s global standing.^[51] Many ASEAN countries value Japan for offering diversification, not only economically, but also diplomatically, helping them avoid over-reliance on China.^[52]

Third, the OSA framework has also drawn scrutiny for potentially undermining Japan’s pacifist principles, as enshrined in Article 9 of its post-Second World War Constitution. Critics within Japan argue that providing military equipment to other nations risks entangling Japan in external conflicts, a marked departure from its traditionally non-militaristic foreign policy​. Nonetheless, the OSA fits into a broader reinterpretation of security that does not violate constitutional constraints but instead responds to a sharper regional threat environment. Tokyo justifies the initiative as an extension of its longstanding approach to non-lethal, capacity-building assistance, still distinct from lethal arms transfers or participation in conflict. The primary reasoning is that helping partners improve maritime surveillance, law-enforcement capability, and resilience contributes directly to Japan’s own security, given its dependence on stable sea lanes and a rules-based order. Framed as defensive and preventative, the OSA is presented as consistent with Japan’s pacifist principles while enabling it to address the realities of a more contested Indo-Pacific strategic environment.

Finally, since OSA assistance must exclude items “directly related to international conflict” and is restricted to non-lethal support such as coastal surveillance radars, patrol vessels for law enforcement, or disaster response equipment,^[53] these restrictions mean that while partner states may desire stronger deterrence tools, Japan’s ability to provide lethal or combat-related systems remains off limits. Financial and resource constraints also reduce OSA’s potential impact. Japan’s initial budget allocations towards it have been relatively modest, amounting to only a few billion yen annually. This is small compared to the vast capacity-building needs across the Indo-Pacific, particularly in maritime surveillance and defence infrastructure. Limited budgets mean Japan can support only a handful of projects at a time, and often with equipment or systems that may not fully meet partner expectations.^[54] Logistical and technical hurdles compound the challenge: providing hardware requires sustained commitments to training, maintenance, spare parts, and interoperability−areas where Japan has limited institutional experience.

​While OSA represents a critical innovation in Japan’s security statecraft, its effectiveness will be incremental, involving the building of symbolic trust, modestly enhancing partner capacities, and signalling Japan’s willingness to share security responsibilities without breaching its constitutional limits. Whether the OSA evolves into a more transformative tool will depend on Japan’s ability to gradually ease its domestic constraints, increase budgetary commitments, and align its efforts with broader alliance and regional initiatives. The success of the policy will depend on the country’s ability to navigate these complexities, build trust with partner nations, and ensure that its initiatives contribute to long-term regional stability.

Conclusion

For too long, Tokyo’s foreign policy was constrained by the moral and constitutional limits of its pacifist legacy—a constraint that, while once necessary, had become increasingly incongruent with the realities of a contested Indo-Pacific. The OSA represents an acknowledgement that Japan’s economic strength and technological sophistication must now be matched by an ability to contribute meaningfully to regional security. It is not a departure from pacifism, but an evolution towards strategic maturity.

This shift is timely. The Indo-Pacific is no longer a stable maritime space; it is the arena of renewed competition where coercion, grey-zone operations, and militarised expansionism have become routine. Japan’s traditional reliance on ODA and alliance-based deterrence can no longer secure its interests or those of its partners. By developing a framework for non-lethal security assistance, Japan has entered the strategic domain as a responsible provider of regional public goods, including maritime domain awareness, humanitarian support, and infrastructure resilience. OSA gives substance to Japan’s Free and Open Indo-Pacific vision, translating normative aspiration into policy action.

Tokyo can meaningfully expand its OSA by broadening both its geographic reach and the types of security capabilities it supports, institutionalising a future-oriented model that reinforces its proactive defence posture.

First, Tokyo should deepen OSA engagement with island and littoral states in the Indo-Pacific, particularly those in the Pacific and Indian Oceans, by extending support to more partner nations and increasing the scale of projects. Already, in FY 2025, it has expanded to new recipients, including Papua New Guinea and Sri Lanka.^[55] By bringing in countries strategically located along critical sea lanes, Japan can enhance regional maritime security. Second, Japan can diversify the types of non-lethal defence capabilities it funds. Beyond coastal radars, it could provide patrol vessels, UAVs (Unmanned Aerial Vehicles), and command-and-control platforms, strengthening partners’ surveillance, disaster relief, and maritime resilience capacities. For example, in FY 2025, OSA already includes UAVs for Sri Lanka’s navy and a surveillance ship for Malaysia. Third, Tokyo needs to scale up its institutional architecture for OSA, building on its current security cooperation office at MOFA. Analysts have argued that more strategic use of OSA requires better coordination, long-term planning, and clearer disclosure of project rationales.^[56] By combining these measures, strategic expansion, capability diversity, and institutional strengthening, Japan can evolve OSA into a cornerstone of its forward-leaning defence diplomacy, helping deter coercion and bolster multilateral security in the Indo-Pacific.

To be sure, strategic restraint is not synonymous with strategic passivity. The region’s security architecture demands a Japan that can lead, and not only finance. Ultimately, the OSA’s success will depend not on the scale of its grants but on how effectively it reinforces Japan’s role as a credible and consistent security contributor to the Indo-Pacific. The country is already recognised as a dependable partner not only in Southeast Asia but across the Indo-Pacific—its challenge now is to align its strategic intent with tangible and sustained capacity-building outcomes. The opportunity lies in ensuring that the OSA evolves beyond a funding mechanism into a durable framework for collective security, deterrence, and stability. In doing so, Japan can consolidate its long-standing commitment to peace with the responsibilities demanded by a more uncertain strategic environment.

---

Pratnashree Basu is Associate Fellow (Indo-Pacific), Strategic Studies Programme, Observer Research Foundation.

---

All views expressed in this publication are solely those of the author, and do not represent the Observer Research Foundation, either in its entirety or its officials and personnel.

Endnotes

^[a] These four are Habomai, Shikotan, Kunashiri, and Etorofu.

^[b] Hari’i Hamutuk (“Building Together”) is an annual multilateral military engineering exercise in Timor-Leste, led by the Australian Defence Force with partners including the US, Japan, and New Zealand, aimed at building infrastructure and enhancing regional interoperability and resilience. The exercise combines engineering, medical, and logistics training with on-ground construction of military and community facilities, strengthening both local capacity and regional defence partnerships.

^[c] The Philippines occupies a critical position in the Indo-Pacific, both geographically and strategically. Its extensive coastline, proximity to key sea lanes, and role in regional maritime security make it a natural partner for countries invested in a stable and rules-based maritime order. The US, Japan, India, and other countries are engaging with the Philippines to strengthen collective security initiatives. These partnerships are mutually beneficial in that they help the Philippines safeguard its maritime interests while enabling external partners to ensure free and secure access through vital shipping routes in the region.

^[d] Japanese companies have historically struggled to secure defence export deals with India, and the much-talked-about Shin Maywa US-2 amphibious aircraft deal has been delayed for years. Negotiations over pricing, offsets, and delivery have stalled repeatedly. However, Japan is gradually breaking into defence exports, and the landscape is evolving. For example, Japan signed an agreement to transfer a stealth antenna system (UNICORN) to India in November 2024.

^[1] Ministry of Foreign Affairs, Government of Japan, “Northern Territories Issue,” https://www.mofa.go.jp/region/europe/russia/territory/overview.html

^[2] The White House, “National Security Strategy of the United States of America,” November 2025, https://www.whitehouse.gov/wp-content/uploads/2025/12/2025-National-Security-Strategy.pdf

^[3] Ministry of Foreign Affairs, Government of Japan, “National Security Strategy of Japan,” December 2022, https://www.cas.go.jp/jp/siryou/221216anzenhoshou/nss-e.pdf

^[4] Ministry of Defence, Government of Japan, “National Defence Strategy of Japan,” December 2022, https://www.mod.go.jp/j/policy/agenda/guideline/strategy/pdf/strategy_en.pdf

^[5] Ministry of Foreign Affairs, Government of Japan, “Defence Buildup Program,” December 2022, https://www.cas.go.jp/jp/siryou/221216anzenhoshou/nss-e.pdf

^[6] Ministry of Defence, Government of Japan, “National Defence Strategy,” December 16, 2022, https://www.mod.go.jp/j/policy/agenda/guideline/strategy/pdf/strategy_en.pdf

^[7] Ministry of Foreign Affairs, Government of Japan, “National Security Strategy of Japan”

^[8] “China Threat and the New Japanese Defence White Paper,” Observer Research Foundation, August 16, 2011, https://www.orfonline.org/research/china-threat-and-the-new-japanese-defence-white-paper

^[9] Toshiya Takahashi, “A New Trend in Japan’s Defence White Paper,” East Asia Forum, August 21, 2012, https://eastasiaforum.org/2012/08/21/a-new-trend-in-japans-defence-white-paper/

^[10] Ministry of Defence, Government of Japan, “Defence of Japan 2019,” https://www.mod.go.jp/en/publ/w_paper/wp2019/pdf/index.html

^[11] “Japan defence white paper says China’s military ambitions ‘greatest strategic challenge’ to the world”, South China Morning Post, July 12, 2024, https://www.scmp.com/news/asia/east-asia/article/3270181/japan-defence-white-paper-says-chinas-military-ambitions-greatest-strategic-challenge-world

^[12] Security Environment Surrounding Japan, Defence of Japan, 2025, https://www.mod.go.jp/j/press/wp/wp2025/pdf/DOJ2025_Digest_EN.pdf

^[13] Jeffrey W. Hornung, “Boosting Japan’s Proactive Contributions to Peace,” Sasakawa Peace Foundation, October 27, 2015, https://spfusa.org/publications/boosting-japans-proactive-contributions-to-peace/#:~:text=More%20actively%20support%20capacity%20building,patrol%20vessels%20to%20the%20Philippines

^[14] Takashi Shiraishi, “Abe’s Visit to Southeast Asia and Japan’s Five New Diplomatic Principles,” Nippon, January 30, 2013, https://www.nippon.com/en/column/f00016/

^[15] Prime Minister’s Office of Japan, “Press Conference by Prime Minister Shinzo Abe following the ASEAN-Japan Commemorative Summit,” December 14, 2013, https://japan.kantei.go.jp/96_abe/statement/201312/14kaiken_e.html

^[16] Shinzo Abe, “Asia’s Democratic Security Diamond,” Project Syndicate, December 27, 2012, https://www.project-syndicate.org/magazine/a-strategic-alliance-for-japan-and-india-by-shinzo-abe

^[17] Ministry of Defence, Government of Japan, “Defence of Japan 2025,” https://www.mod.go.jp/en/publ/w_paper/index.html

^[18] Jeffrey W. Hornung, “Boosting Japan’s Proactive Contributions to Peace,” Sasakawa Peace Foundation, October 27, 2015, https://spfusa.org/publications/boosting-japans-proactive-contributions-to-peace/

^[19] Jeffrey W. Hornung, “Boosting Japan’s Proactive Contributions to Peace”

^[20] Ippeita Nishida, “Outstanding Issues for Official Security Assistance (OSA) and its Strategic Utilisation,” Sasakawa Peace Foundation, November 8, 2023, https://www.spf.org/iina/en/articles/nishida_03.html

^[21] US Department of War, “Philippines, U.S. Announce Locations of Four New EDCA Sites,” April 3, 2023, https://www.war.gov/News/Releases/Release/Article/3349257/philippines-us-announce-locations-of-four-new-edca-sites/

^[22] Ministry of Foreign Affairs, Japan, “The Three Principles on Transfer of Defense Equipment and Technology,” https://www.mofa.go.jp/fp/nsp/page1we_000083.html

^[23] Sato Heigo, “Japan’s New Arms Export Policy: An Unfinished Breakthrough”, Nippon, March 7, 2024, https://www.nippon.com/en/in-depth/d00984/

^[24]  Pratnashree Basu, “The Strategic Impact of the Japan–Australia Frigate Deal,” Observer Research Foundation, August 27, 2025, https://www.orfonline.org/expert-speak/the-strategic-impact-of-the-japan-australia-frigate-deal

^[25] Purnendra Jain, “Japan’s new security assistance to the Indo-Pacific region,” Observer Research Foundation, January 8, 2024, https://www.orfonline.org/expert-speak/japan-s-new-security-assistance-to-the-indo-pacific-region

^[26] Ippeita Nishida, “Outstanding Issues for Official Security Assistance (OSA) and its Strategic Utilisation”

^[27] Official Security Assistance (OSA), Programme in implementation FY2024, Japan’s Security Policy, Ministry of Foreign Affairs of Japan, March 13, 2025, https://www.mofa.go.jp/fp/ipc/pagewe_001067_00001.html

^[28] Ippeita Nishida, “Outstanding Issues for Official Security Assistance (OSA) and its Strategic Utilisation”

^[29] Gabiel Dominguez, “Japan aims to double number of military aid recipients this year,” The Japan Times, June 23, 2025, https://www.japantimes.co.jp/news/2025/06/23/japan/japan-official-security-assistance-2025/

^[30] Ministry of Foreign Affairs of Japan, “Three Principles on Transfer of Defence Equipment and Technology,” https://www.mofa.go.jp/fp/nsp/page1we_000083.html

^[31] “Abe’s Moves Toward Collective Self-Defence,” Nippon, July 11, 2014, https://www.nippon.com/en/features/h00062/abe%E2%80%99s-moves-toward-collective-self-defense.html

^[32] Ippeita Nishida, “Revising the Development Cooperation Charter:  Issues in Linking ODA and Security,” Sasakawa Peace Foundation, August 10, 2022, https://www.spf.org/iina/en/articles/nishida_02.html

^[33] Manu Pubby, “Quad's $50-billion, 5-year infra booster for Indo-Pacific,” The Economic Times, May 25, 2022, https://economictimes.indiatimes.com/news/india/quads-50-billion-5-year-infra-booster-for-indo-pacific/articleshow/91776640.cms?from=mdr

^[34] Ministry of Foreign Affairs, Japan, “Keynote Address by Prime Minister Kishida at the IISS Shangri-La Dialogue 2022,” June 10, 2022, https://www.mofa.go.jp/fp/nsp/page3e_001212.html

^[35] Ippeita Nishida, “Revising the Development Cooperation Charter:  Issues in Linking ODA and Security”

^[36] Ministry of Foreign Affairs, Japan, “Official Security Assistance (OSA),” April 23, 2025, https://www.mofa.go.jp/fp/ipc/page4e_001366.html

^[37] Jumpei Ishimaru, “Japan’s shifting foreign-assistance schemes,” IISS, April 22, 2024, https://www.iiss.org/online-analysis/online-analysis/2024/04/japans-shifting-foreign-assistance-schemes

^[38] Ministry of Foreign Affairs, Japan, Official Security Assistance, OSA, https://www.mofa.go.jp/fp/ipc/page4e_001366.html

^[39] Ministry of Foreign Affairs, Japan, “FY2024 Domestic Public Opinion Survey on Japan’s Diplomacy,” https://www.mofa.go.jp/files/100807389.pdf

^[40] Ministry of Foreign Affairs, Japan, “FY2024 Domestic Public Opinion Survey on Japan’s Diplomacy”

^[41] Shohei Sasagawa, “Survey: Support for bolstered national defence remains high,” The Asahi Shimbun, March 8, 2023, https://www.asahi.com/ajw/articles/14902677

^[42] ROLES Survey, “Security, Alliance, and Foreign Engagement Research (SAFER)” project, University of Tokyo, October 2024, https://roles.rcast.u-tokyo.ac.jp/uploads/publication/file/130/publication.pdf

^[43] ROLES Survey, “Security, Alliance, and Foreign Engagement Research (SAFER)” project, University of Tokyo, March 2025, https://roles.rcast.u-tokyo.ac.jp/uploads/publication/file_english/163/publication.pdf

^[44] ROLES Survey, “Security, Alliance, and Foreign Engagement Research (SAFER)”

^[45] Ministry of Foreign Affairs, Japan, “FY2024 Domestic Public Opinion Survey on Japan’s Diplomacy”

^[46] Yuki Tatsumi, “Japan's defence spending: Drivers and headwinds,” United States Studies Centre, March 1, 2024, https://www.ussc.edu.au/japan-s-defence-spending-drivers-and-headwinds

^[47] Ippeita Nishida, “How will OSA change security cooperation?,” Japan Foreign Policy Forum, July 5, 2024, https://www.japanpolicyforum.jp/diplomacy/pt2024070512023914397.html

^[48] Nobuhiro Aizawa and Ben Bland, “Japan Is Well-positioned to Counterbalance China in Southeast Asia,” Debating Japan vol 3 Issue 5, CSIS, July 1, 2020, https://www.csis.org/analysis/resolved-japan-well-positioned-counterbalance-china-southeast-asia

^[49] Gabriel Dominguez, “With China in mind, Japan expands security ties with ASEAN”, The Japan Times, December 18, 2023, https://www.japantimes.co.jp/news/2023/12/18/japan/politics/japan-asean-security-cooperation-analysis/

^[50] Dr. Denis Suarsana, “How China and Japan are Competing for Economic Dominance in Southeast Asia”, Konrad-Adenauer-Stiftung, September 17, 2025, https://www.kas.de/en/web/auslandsinformationen/artikel/detail/-/content/how-china-and-japan-are-competing-for-economic-dominance-in-southeast-asia

^[51] Ippeita Nishida, “How will OSA change security cooperation?”

^[52] Alexandra Sakaki, “Japan in Southeast Asia: Countering China’s Growing Influence”, SWP Research Paper, June 2025, https://www.swp-berlin.org/publications/products/research_papers/2025RP01_JapanSoutheastAsia.pdf

^[53] Ministry of Foreign Affairs, Japan, “Implementation Guidelines for Japan’s Official Security Assistance”, https://www.mofa.go.jp/files/100487375.pdf

^[54] Ryosuke Hanada, “Japan’s pioneering policy to bridge the Indo-Pacific’s capacity gap”

^[55] Ministry of Foreign Affairs of Japan, Official Security Assistance (OSA) - Programme in implementation FY2025, October 30, 2025, https://www.mofa.go.jp/fp/ipc/pagewe_000001_00268.html

^[56] Ippeita Nishida, “Outstanding Issues for Official Security Assistance (OSA) and its Strategic Utilization”

• International Affairs
• China
• The Pacific
• East Asia
• East China Sea
• japan military assistance programme
• japan military diplomacy
• japan national security strategy
• official security assistance Japan
• osa framework
• osa framework japan

The views expressed above belong to the author(s). ORF research and analyses now available on Telegram! Click here to access our curated content — blogs, longforms and interviews.