Japan Security Report — September 28, 2026

Security analysis based on open-source intelligence and web research. Period: September 21 — September 28, 2026.

Executive Summary

Japan has actively reinforced its security posture and diplomatic alliances during the period from September 21 to September 28, 2026, amidst escalating regional tensions and evolving global security challenges. Key developments include robust trilateral military exercises with the United States and South Korea, aimed at enhancing interoperability and deterrence against North Korean threats. Concurrently, Japan has advanced its defense capabilities, with plans to integrate long-range missiles into upcoming joint drills and a long-term strategy to significantly increase defense spending. Diplomatic efforts focused on strengthening ties with the U.S. and other Indo-Pacific partners, while navigating complex relations with China, which continues to criticize Japan's defense buildup and stance on Taiwan. Cybersecurity initiatives have also seen progress, with new government guidelines and private sector services launched to protect critical infrastructure.

Key Security Developments

• Trilateral Freedom Edge Drills Enhance Interoperability
  From September 27, 2026, Japan, the Republic of Korea (ROK), and the United States conducted the "Freedom Edge" multidomain exercise, the fourth iteration since June 2024. These drills, held across international waters and airspace south and east of the ROK and at defense installations in Japan, focused on strengthening interoperability, force readiness, cyber defense coordination, and medical training. The exercise involved six naval destroyers, fighter jets, helicopters, maritime patrol aircraft, and refueling tankers, and was explicitly aimed at countering North Korean nuclear and missile threats, coinciding with Pyongyang's commissioning of the nuclear-capable destroyer Kang Kon.

• Japan-U.S. Keen Sword Exercise to Integrate Long-Range Missiles
  A major Japan-U.S. joint drill, "Keen Sword," scheduled to commence in October, is expected to involve the Japanese Ground Self-Defense Force's (JGSDF) long-range missiles. The Japanese Defense Ministry is considering transporting Type-25 surface-to-ship guided missiles from Camp Kengun to Oyanohara Maneuver Area in Kumamoto Prefecture for the exercise. While actual firing will not occur, the exercise will focus on information sharing regarding targets and confirmation of launch procedures, signaling Japan's advancement in acquiring counterstrike capabilities.

• North Korea Conducts Ballistic Missile Launches
  On Sunday, September 20, 2026, North Korea fired two suspected short-range ballistic missiles towards the Sea of Japan (East Sea). The first missile traveled approximately 279 miles, and the second flew over 373 miles. Japan's Defense Ministry reported the suspected launches, confirming that neither missile landed within Japanese territorial waters. This event underscores the persistent and immediate ballistic missile threat posed by North Korea to regional security.

• ADMM-Plus Maritime Security Exercise Co-Chaired by Japan and Philippines
  From September 20 to 26, 2026, U.S. naval forces joined maritime forces from the ASEAN Defense Ministers' Meeting-Plus (ADMM-Plus) Experts' Working Group on Maritime Security Joint Cooperative Activity (MS JCA). Co-hosted by Japan and the Philippines in Olongapo City, Zambales, the exercise involved personnel, naval vessels, aircraft, and assets from eight ADMM-Plus countries, including Australia, Brunei, India, New Zealand, Singapore, and the United States. The activity aimed to foster cooperation, enhance collective maritime domain awareness, and strengthen regional resilience against natural disasters.

• Japan Considers Nuclear Submarine Fleet Development
  Japan is reportedly considering the use of nuclear propulsion for its future submarine fleet. On September 22, 2026, it was reported that Defense Minister Shinjiro Koizumi stated Japan would "not rule out" acquiring nuclear submarines (SSNs). This potential shift is seen as a significant enhancement to Japan's ability to independently counter the People's Liberation Army Navy's (PLAN) modernization and expansion, offering advantages in operating range, speed, and stealth compared to conventional diesel-electric submarines.

• China and Russia Protest Japan's Typhon Missile System Deployment
  On September 21, 2026, China's Foreign Ministry spokesperson Guo Jiakun reiterated strong protests against Japan's deployment of the U.S. Typhon ground-based missile system on Kyushu Island. This followed a Russian protest note on September 3, with both nations labeling the Typhon system as a strategic offensive weapon and accusing Japan of "accelerated remilitarization". They warned that such a move increases the risk of military confrontation and an arms race, threatening regional stability.

• Record Defense Budget Request Prioritizes AI and Next-Gen Tech
  Japan's Defense Ministry has requested a record ¥8.9 trillion (approximately $55.6 billion to $60.1 billion) for fiscal year 2027. This proposed budget prioritizes investments in artificial intelligence (AI) and next-generation military technologies, including AI-powered decision-support systems, low-cost drones, long-range missiles, and submarine-launched hypersonic weapons. Tokyo also plans to establish a new unit to counter "cognitive warfare" and disinformation, reflecting growing security concerns involving China, North Korea, and Russia.

• Fujitsu Launches Advanced Cyber Defense Service
  On September 25, 2026, Fujitsu Limited launched a new security service designed to support active cyber defense for enterprises and critical infrastructure operators. The service integrates dark web monitoring, attack surface management, and threat hunting, leveraging threat intelligence from KELA KK to proactively identify potential cyber risks and facilitate early countermeasures. This initiative aligns with the Japanese government's promotion of active cyber defense measures to detect warning signs of attacks before damage occurs.

• Japan-U.S.-ROK Foreign Ministers' Meeting on Regional Stability
  On September 21, 2026, in New York, the Foreign Ministers of Japan, the U.S., and the ROK held a meeting reaffirming their solidarity as pivotal to regional peace and stability. They welcomed steady progress in security cooperation, including joint exercises and cybersecurity, as well as economic security and energy initiatives like supply chain resilience. The ministers also concurred on advancing cooperation in international disaster relief and combating transnational organized crime in Southeast Asia, while reaffirming commitment to North Korea's complete denuclearization.

• PM Takaichi Addresses UN General Assembly on Global Threats
  On September 22, 2026, Prime Minister Sanae Takaichi addressed the 81st U.N. General Assembly in New York. She warned that North Korea's advancing nuclear and missile programs, alongside its use of cyber activities for funding, pose a serious threat to international peace and security. Takaichi also expressed concern over growing military cooperation between Russia and North Korea, highlighted emerging risks from artificial intelligence, and called for reforms to the United Nations, including the prompt deletion of "enemy state" clauses in the UN Charter.

• Japan's Defense Ministry to Support UAV Development Startups
  On September 27, 2026, Japan's Defense Ministry announced a new contract system to support startups in developing unmanned aerial vehicles (UAVs) and other defense products. This initiative, which will publicly solicit applications from early October, aims to tap into advanced civilian technologies for defense equipment. The ministry's research and development targets include low-cost UAVs using domestically made components, boosting operational efficiency in supply warehouses, and reducing aircraft noise at bases.

Geopolitical Impact and Regional Dynamics

Japan's security developments over the past week underscore a proactive and assertive approach to regional stability, primarily driven by concerns over China's growing influence and North Korea's persistent threats. The Freedom Edge trilateral exercises with the U.S. and South Korea, and the upcoming Keen Sword drills, demonstrate Japan's commitment to strengthening alliances and enhancing deterrence capabilities in the Indo-Pacific. This deepening security cooperation, particularly with the U.S., is a cornerstone of Japan's strategy to balance China's military modernization and assertive actions in the East and South China Seas. However, these joint exercises and Japan's broader defense buildup are viewed by China and Russia as "accelerated remilitarization," leading to strong diplomatic protests and heightened rhetoric from Beijing and Moscow.

The ongoing diplomatic crisis between Japan and China, stemming from Prime Minister Takaichi's November 2025 remarks on Taiwan, continues to strain bilateral relations. China's retaliatory economic measures and accusations of "neo-militarism" against Japan highlight the fragility of their relationship and the potential for further escalation, particularly concerning the Taiwan Strait. Japan's participation in the ADMM-Plus maritime security exercise, co-chaired with the Philippines, also signals its intent to bolster cooperation with Southeast Asian nations to uphold a free and open maritime order, implicitly countering China's expansive maritime claims.

The recent U.S.-China summit and President Trump's remarks referring to China as a WWII ally have caused apprehension in Tokyo, raising concerns about potential U.S.-China rapprochement that could sideline Japan. Despite Prime Minister Takaichi's efforts to align strategies with President Trump ahead of the summit and reaffirm the strong Japan-U.S. alliance, the perception of being potentially marginalized in major power dynamics adds a layer of complexity to Japan's diplomatic calculations. Overall, Japan's actions reflect a determined effort to solidify its security architecture through alliances and enhanced capabilities, while navigating a volatile geopolitical landscape marked by great power competition and regional flashpoints.

Military and Defense Analysis

Japan's military and defense posture is undergoing a significant transformation, moving away from its traditionally exclusively defense-oriented policy. The proposed record defense budget of ¥8.9 trillion for fiscal year 2027, with a long-term goal of reaching 3.5% of GDP, underscores a sustained commitment to modernizing its Self-Defense Forces (SDF). This substantial increase in spending is earmarked for advanced capabilities, including AI-powered decision-support systems, low-cost drones, long-range missiles, and submarine-launched hypersonic weapons, reflecting lessons learned from contemporary conflicts like the war in Ukraine. The emphasis on stand-off defense capabilities and counterstrike capabilities, as evidenced by the deployment of Type-25 surface-to-ship guided missiles and their integration into upcoming exercises, represents a strategic shift towards projecting power beyond its immediate borders.

The consideration of acquiring nuclear-powered submarines (SSNs) marks a potentially profound development in Japan's naval capabilities. SSNs would offer significantly greater operating range, speed, and stealth compared to Japan's current diesel-electric fleet, enhancing its ability to counter the People's Liberation Army Navy (PLAN) across the Western Pacific. This move, if realized, would dramatically alter Japan's force posture and its role in regional maritime security. Furthermore, the Defense Ministry's new contract system to support startups in UAV development highlights an agile approach to defense acquisitions, aiming to rapidly integrate innovative civilian technologies into military applications. This focus on indigenous development, alongside the acquisition of foreign systems like Tomahawk missiles, aims to strengthen Japan's domestic defense industry and reduce reliance on external supply chains. The deployment of the U.S. Typhon ground-based missile system on Kyushu, despite protests from China and Russia, further solidifies Japan's integrated air and missile defense capabilities, particularly in its southwestern islands, which are strategically vital for defending the eastern approaches to Taiwan.

Outlook and Forecast

Short-term trends (1-3 months): In the immediate future, Japan is expected to continue its robust engagement in multilateral military exercises, particularly with the U.S. and South Korea, to reinforce deterrence against North Korea and manage China's regional assertiveness. The upcoming Keen Sword exercise in October, involving Japanese long-range missiles, will be a key indicator of Japan's evolving counterstrike capabilities and its commitment to a more proactive defense posture. Diplomatic tensions with China are likely to persist, especially given Beijing's strong reactions to Japan's defense buildup and its stance on Taiwan. Japan will also likely finalize and implement new cybersecurity guidelines for critical infrastructure by the end of September, leading to increased vigilance and investment in cyber defense across key sectors. The Defense Ministry's new initiative to support UAV startups will begin soliciting applications in early October, signaling a push for rapid technological integration in defense.

Critical flashpoints and risk areas: The Taiwan Strait remains a critical flashpoint, with Japan's explicit statements on a potential Chinese attack constituting an "existential crisis" for Japan continuing to fuel tensions with Beijing. Any significant military activity or escalation in the Taiwan Strait would directly impact Japan's security. The Senkaku Islands (Diaoyu Islands) in the East China Sea also remain a persistent area of dispute and potential confrontation with China, where unilateral attempts to change the status quo are closely monitored. North Korea's continued ballistic missile tests and nuclear program pose an ongoing and unpredictable threat, necessitating constant vigilance and robust missile defense cooperation. The deployment of the U.S. Typhon missile system on Kyushu has drawn strong condemnation from China and Russia, creating a new point of contention that could escalate rhetorical exchanges or lead to counter-deployments in the region.

Indicators to monitor: Key indicators to monitor include the scope and frequency of joint military exercises involving Japan, the U.S., and South Korea, particularly any expansion in their complexity or geographic reach. Statements and actions from China and Russia regarding Japan's defense buildup, especially concerning missile deployments and potential nuclear submarine development, will be crucial. The progress of Japan's defense budget approval and the specific allocation of funds to AI, drones, and long-range strike capabilities will indicate the pace of its military modernization. Furthermore, any shifts in U.S.-China relations, particularly those that might affect the U.S. commitment to its allies in the Indo-Pacific, will be closely watched by Tokyo.

Strategic recommendations: Japan should continue to strengthen its alliances, particularly with the U.S. and South Korea, to present a united front against regional threats and ensure collective security. Diversifying security partnerships beyond traditional allies, as seen with the ADMM-Plus exercise, will enhance regional stability and burden-sharing. Japan should also maintain clear and consistent communication with China to manage diplomatic tensions, while firmly upholding its sovereign interests and international law in disputed areas. Accelerating domestic defense industrial base development, especially in cutting-edge technologies like AI and drones, is vital for long-term self-reliance and technological superiority. Finally, continued investment in cybersecurity infrastructure and capabilities, both governmental and private, is essential to protect critical national assets from increasingly sophisticated cyber threats.

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