Japan Security Report — April 10, 2026

Security analysis based on open-source intelligence and web research. Period: April 03 — April 10, 2026.

Security Analysis Report: Japan (April 03, 2026 - April 10, 2026)

Executive Summary

Japan has significantly advanced its defense posture, notably deploying long-range "counterstrike" missiles for the first time and accelerating its defense spending to 2% of GDP by March 2026. This period also saw Japan's Ground Self-Defense Force participate in major multinational military exercises in the Philippines, marking a historic shift in its regional security engagement. Concurrently, Japan is preparing to launch "proactive cyber-defense" operations from October 2026, reflecting a growing emphasis on offensive cyber capabilities amidst persistent cyber threats. Diplomatic efforts focused on de-escalating the Iran situation and strengthening alliances, while delays in critical defense acquisitions highlight the broader geopolitical strains. These developments underscore Japan's rapid militarization and expanding role in Indo-Pacific security, driven by an increasingly complex regional environment.

Key Security Developments

• Deployment of Long-Range "Counterstrike" Missiles
  This week, the Ground Self-Defense Force (GSDF) deployed long-range Type 25 surface-to-ship missiles, capable of reaching targets up to 1,000 km away, at Camp Kengun in Kumamoto Prefecture. Additionally, hyper velocity gliding projectiles (HVGP) were deployed to Camp Fuji near Gotemba in Shizuoka Prefecture. This marks the first time Japan has adopted offensive strike capabilities, signaling a crucial evolution in its defense strategy to deter potential adversaries like China and North Korea.

• Acceleration of Defense Spending Target
  Japan has accelerated its five-year program to double annual defense spending to 2% of its Gross Domestic Product (GDP) by March 2026, two years earlier than initially planned. The Cabinet approved a record draft defense budget of 9.04 trillion yen ($58 billion) for fiscal year 2026, representing a 9.4% increase from 2025. This substantial increase is a direct response to the "severest and most complex security environment since the end of World War II" and aims to bolster Japan's deterrence and response capabilities.

• First-Time Participation in Salaknib Military Exercises
  From April 6-17, 2026, Japan's Ground Self-Defense Force (GSDF) is participating for the first time in the annual Salaknib military exercises in the Philippines, alongside the Philippine Army and the United States Army Pacific (USARPAC). Approximately 420 GSDF members are involved in these drills, held at the Ramon Magsaysay Base in Nueva Ecija Province, focusing on infantry combined-arms operations and humanitarian assistance. This marks a historic breakthrough, as Japanese combat troops have set foot on Philippine soil for the first time since World War II, signaling a rapid acceleration of a trilateral military network in the Indo-Pacific.

• Preparation for Offensive Cyber Operations
  Japan is set to operationalize "proactive cyber-defense" (offensive cyber operations) starting October 1, 2026. This policy shift, rooted in the Active Cyberdefense Law enacted in May 2025, grants the government authority to infiltrate and disable hostile servers before an attack occurs. Chief Cabinet Secretary Minoru Kihara emphasized this as a critical front for national security, given the increasing impact of cyberattacks on people's lives and economic activities.

• Delays in Tomahawk Missile Deliveries
  Japan's order for approximately 400 Tomahawk missiles from the United States faces delays, with Washington informing Tokyo that deliveries by March 2028 would be disrupted. This delay is attributed to the strain on US inventories caused by their use in the American-Israeli war with Iran. This impacts Japan's defense modernization plans, particularly the equipping of its Aegis-equipped destroyers with these long-range missiles.

• Strengthening Pacific Ocean Defense System
  Japan plans to strengthen its defense system in the Pacific Ocean, driven by increasing Chinese military activities in the area. The Defense Ministry established a Pacific defense concept office this month to examine concrete measures. Defense Minister Shinjiro Koizumi highlighted a "defense vacuum" in a vast area on the Pacific side, emphasizing the need to expand the presence of the Self-Defense Forces and develop a radar network, particularly around islands like Iwoto and Minamitorishima.

• Ongoing Cybersecurity Incidents
  Throughout March 2026, Japan experienced a continued pattern of cybersecurity incidents across various sectors, including healthcare, precision manufacturing, and public institutions. Notable disclosures include a third update on an unauthorized access incident at the National Diet Library and ransomware attacks on Medica Publishing and Nihon Swagelok FST. These incidents underscore Japan's expanding cyberattack surface and the persistent threat from both financially motivated ransomware actors and state-directed espionage groups.

• Diplomatic Engagements on Iran Situation
  Foreign Minister Toshimitsu Motegi held telephone conversations with foreign ministers of G7 countries, Gulf states, Türkiye, Saudi Arabia, and Kuwait, as well as parties to the conflict, to discuss the tense situation in Iran. Japan is actively engaging in diplomatic efforts to seek early de-escalation and ensure the safety of navigation in critical waterways like the Strait of Hormuz. Prime Minister Sanae Takaichi also affirmed Japan's commitment to providing strong support and engaging with various countries to resolve the situation.

• Japan-France Counter-Terrorism Consultations
  The Second Japan-France Counter-Terrorism Consultations took place on April 3, 2026. These consultations are part of Japan's broader efforts to strengthen international cooperation against terrorism, building on previous engagements and its "3-Pillar Foreign Policy" formulated in 2015.

• Easing of Nuclear Plant Anti-Terrorism Facility Deadlines
  On April 2, 2026, the Nuclear Regulation Authority approved a plan to ease the deadline for installing anti-terrorism facilities at nuclear power plants. The five-year completion period will now start when a nuclear reactor begins operation, rather than when regulatory approval for construction is given. This change aims to prevent the suspension of reactor operations for plants facing tight deadlines, such as the Onagawa plant in Miyagi Prefecture.

Geopolitical Impact and Regional Dynamics

Japan's security developments this week underscore a profound and rapid shift in its strategic posture, driven by an increasingly volatile Indo-Pacific and global landscape. The deployment of long-range "counterstrike" missiles and the accelerated defense spending to 2% of GDP by March 2026 signal Japan's determination to enhance its deterrence capabilities and take on a more proactive role in regional security. This move, while aimed at deterring potential aggression from China and North Korea, is viewed with unease by some regional actors, particularly China, which sees Japan's participation in overseas drills as bypassing its pacifist constitution and accelerating a trilateral military network with the US and the Philippines.

The historic participation of Japan's Ground Self-Defense Force in the Salaknib exercises in the Philippines, and anticipated involvement in Balikatan, is a clear manifestation of Japan's expanding security cooperation beyond its immediate borders. This deepening alignment with the US and the Philippines, particularly in the context of maritime territorial disputes in the East and South China Seas, directly impacts regional stability by strengthening a united front against China's assertive actions. However, it also risks exacerbating tensions with Beijing, which views such exercises as part of an "Indo-Pacific Strategy" aimed at containment.

Relations with major powers are complex. The US-Japan alliance remains the cornerstone of Japan's foreign policy, with Japan accelerating defense spending and deepening operational integration. However, the ongoing US-Israeli war with Iran has directly impacted Japan's defense acquisitions, causing delays in Tomahawk missile deliveries, highlighting the interconnectedness of global conflicts and supply chain vulnerabilities. Japan's diplomatic efforts to de-escalate the Iran situation, engaging with both Western and Middle Eastern nations, demonstrate its desire to maintain stability in energy-critical regions and leverage its unique diplomatic channels. Meanwhile, Japan's relations with Russia remain "severe" due to the Ukraine conflict, with Tokyo rejecting reports of sending an economic delegation to Moscow.

Military and Defense Analysis

Japan's military and defense posture is undergoing a significant transformation, moving beyond its traditional "exclusive defense" policy. The deployment of Type 25 land-based anti-ship missiles at Camp Kengun, Kumamoto, and Type 25 high-speed glide missiles at Camp Fuji, Shizuoka, represents a tangible acquisition of "counterstrike capabilities" with ranges up to 1,000 km. This is complemented by plans to equip all eight Aegis-equipped destroyers with US-made Tomahawk missiles (range ~1,600 km) and ASDF F-35As with Norwegian-made Joint Strike Missiles (range ~500 km), though Tomahawk deliveries are currently delayed. These developments significantly enhance Japan's ability to deter aggression by threatening enemy launch sites.

Modernization programs are also evident in the record defense budget of 9.04 trillion yen ($58 billion) for fiscal 2026, which marks the fourth year of a five-year plan to double defense spending to 2% of GDP. This budget allocates substantial funds for stand-off missile capabilities, drone technology, and the development of a "Shield" layered coastal defense system incorporating aerial, surface, and underwater vehicles. Japan is also investing over $1 billion in 2026 for the joint development of a next-generation fighter jet with Britain and Italy for deployment in 2035, alongside AI-operated drones designed to fly with the jet. The strengthening of defense in the Pacific Ocean, including potential upgrades to bases like Iwoto and Minamitorishima, further illustrates a strategic shift towards projecting power and surveillance capabilities further afield to counter Chinese activities.

Outlook and Forecast

Short-term trends (1-3 months): In the immediate future, Japan will continue its active participation in multinational military exercises, particularly the ongoing Salaknib drills and the upcoming Balikatan exercises in the Philippines, further solidifying its alliances in the Indo-Pacific. The government will likely continue to emphasize its new "counterstrike capabilities" and the rationale behind them, potentially leading to increased rhetoric from China. Diplomatic efforts regarding the Iran situation will remain a high priority, as Japan seeks to mitigate economic and security impacts, especially concerning energy supplies. Domestically, the implementation of the record defense budget for fiscal 2026, which began in April, will see initial steps in defense acquisitions and modernization programs.

Critical flashpoints and risk areas: The East China Sea, particularly around the Senkaku Islands, remains a critical flashpoint, with the potential for increased Chinese maritime militia activity challenging Japan's maritime security. The South China Sea will also be a focal point, as Japan's enhanced military cooperation with the Philippines could lead to more direct confrontations or heightened tensions with China. The Taiwan Strait remains a significant concern, with Japan's Prime Minister Takaichi having previously stated that Japan's military could get involved if China were to take action against Taiwan. Cybersecurity threats will persist, and the lead-up to the October 1, 2026, operationalization of "proactive cyber-defense" could see an escalation in cyber espionage or attacks targeting Japan.

Indicators to monitor: Key indicators to monitor include the scope and frequency of joint military exercises involving Japan, the US, and regional partners, particularly in the East and South China Seas. Any further deployments of long-range missiles or advancements in Japan's indigenous defense industry should be closely watched. Diplomatic statements from China, North Korea, and Russia regarding Japan's defense posture will be crucial. The progress and impact of Japan's "proactive cyber-defense" capabilities, including any publicly disclosed operations or retaliations, will be important. Furthermore, developments in the US-Israel-Iran conflict and their impact on global supply chains, especially for defense acquisitions, will directly affect Japan's modernization efforts.

Strategic recommendations: Japan should continue to diversify its defense acquisition sources to mitigate risks associated with delays from single suppliers, as seen with the Tomahawk missiles. Strengthening its domestic defense industrial base and fostering international co-development projects, such as the next-generation fighter jet with the UK and Italy, is essential. Diplomatically, Japan should maintain its multi-faceted approach to regional and global crises, leveraging its relationships with both allies and potential adversaries to de-escalate tensions and protect its national interests. Investing further in cybersecurity resilience across critical infrastructure, alongside the development of offensive capabilities, is paramount to safeguard against evolving digital threats. Finally, clear communication of its defense policy shifts to regional partners and international bodies can help manage perceptions and prevent miscalculations, while consistently upholding the principles of a "free and open Indo-Pacific."

Sources

• japantimes.co.jp
• wsws.org
• cgtn.com
• csis.org
• ipdefenseforum.com
• defensehere.com
• medium.com
• gmanetwork.com
• chosun.com
• globaltimes.cn
• japantimes.co.jp
• jicss.org
• digitalassetredemption.com
• theregister.com
• arabnews.jp
• realcleardefense.com
• fdd.org
• japantimes.co.jp
• youtube.com
• youtube.com
• mofa.go.jp
• mofa.go.jp
• japantimes.co.jp
• rfa.org
• ipdefenseforum.com
• australiandefence.com.au
• navalnews.com
• military.com
• rips.or.jp