New Developments in the Japan-U.S. Alliance: Strategic Significance of the Iron Fist Exercises and Security Cooperation Against the Philippines

In February 2026, the Japan-U.S. alliance in Northeast Asia is entering an important new phase. The Iron Fist exercise, which is being conducted primarily in Okinawa Prefecture from February 11 to March 9, and the completion of the transfer of the coastal radar system to the Philippines on the same day, have become symbolic events demonstrating the multilayered development of Japan's security strategy in the Indo-Pacific region.

This year's Iron Fist exercise is a large-scale joint training involving the naval and ground forces of both Japan and the United States, focusing particularly on island defense scenarios and amphibious operations in the southwestern islands. Notably, this exercise marks the first time the Japan Self-Defense Forces have deployed the V-22 Osprey transport aircraft in practical training. This tiltrotor aircraft plays a crucial role in rapid troop deployment between islands due to its vertical takeoff and landing capabilities combined with the range of a fixed-wing aircraft.

Furthermore, the exercise has also seen the first use of the ScanEagle 2 reconnaissance unmanned aerial vehicle, enhancing maritime and land surveillance capabilities. This small UAV can remain airborne for extended periods, providing real-time information collection, surveillance, and reconnaissance (ISR) capabilities. Given that Okinawa Prefecture, the main training location for the exercise, is close to Taiwan, and considering that Japan's Prime Minister has mentioned the possibility of the Self-Defense Forces' involvement in a Taiwan contingency, the strategic implications of this exercise are clear.

The First Island Chain passes through the southwestern islands and occupies a geopolitically critical position in containing China's maritime activities. The Iron Fist exercise can be interpreted as demonstrating the joint operational capabilities of Japan and the U.S. in defending this island chain and preparing for potential Taiwan Strait conflict scenarios. Amid ongoing tensions in Japan-China relations, the conduct of such large-scale exercises indicates Japan's proactive response to changes in the regional security environment.

On February 11, a new milestone in Japan-Philippines security cooperation was achieved. Kazuyoshi Endo, Japan's Ambassador to the Philippines, and Gilbert Teodoro Jr., the Secretary of National Defense, attended a ceremony for the transfer of the coastal radar system provided under Japan's Official Security Assistance (OSA) program. The total cost of this project is approximately 600 million yen, marking Japan's first OSA infrastructure development project for the Philippines.

The Philippines has a vast coastline made up of thousands of islands, but has faced challenges in maritime surveillance due to having only limited vessels, aircraft, and monitoring systems. Security assessments have repeatedly pointed out significant gaps in coastal surveillance capabilities outside of major ports and densely populated areas. The coastal radar system that has been transferred is expected to enhance the Philippine Navy's ability to detect surface targets, support information collection and surveillance activities, and contribute to disaster response and search and rescue operations.

This support is positioned as part of the OSA program, which was launched in 2023. OSA is Japan's unique assistance program that provides support focused on equipment to the armed forces of partner countries, with the Philippines being the first country to have such support announced and also the most prioritized in terms of funding. To date, Japan has provided the Philippines with rigid-hulled inflatable boats (RHIBs), coastal radar systems, and related equipment for the Philippine Air Force's aerial surveillance radar systems.

On January 15, Japan's Foreign Minister Toshimitsu Motegi and Philippine Foreign Minister Maria Lazarus signed an agreement regarding the construction of a boat house and slipway for RHIBs used by the Philippine Navy. The total cost of this project is approximately 900 million yen, positioning it as the first infrastructure development project under the OSA program. At the same time, both countries signed a Reciprocal Access Agreement (RAA), enabling rapid provision of supplies and services between the Self-Defense Forces and the Philippine military.

According to the Japanese Ministry of Foreign Affairs, the Philippines faces important maritime routes, including the South China Sea and the Luzon Strait, and is a key strategic partner in Japan's regional strategy of a "Free and Open Indo-Pacific" (FOIP). In responding to the expansion of China's naval presence, the Philippines has become one of Japan's most important bilateral partners in Southeast Asia. Furthermore, the Philippines is deepening cooperation with Japan and the United States in various fields, including cyber defense.

In addition to the strategic partnership, the Philippines is also increasing its importance as a market for Japan's defense equipment exports. In 2023, the Philippines became the first country to receive a defense system completed under Japan's "Three Principles on Transfer of Defense Equipment" introduced in 2014. This system is the FPS-3ME long-range 3D AESA (Active Electronically Scanned Array) radar, worth approximately $100 million, capable of detecting and tracking multiple aerial targets.

Following the success of Japan's radar exports to the Philippines, Tokyo is considering additional supplies of air systems to deter the increasing military presence of China and enhance interoperability between the Self-Defense Forces and the Philippine military. Reports from December indicate that Japan is considering exporting a command and control system to the Philippines that integrates radar and sensor data to detect and track aircraft and missiles. By adding such capabilities to the radar units already supplied, information sharing between the two countries will be improved.

Philippine defense authorities have reportedly expressed renewed interest in Japan's Type 03 medium-range surface-to-air missile system. If integrated with Japan's radar and command and control systems, the Philippines would be able to conduct end-to-end detection, tracking, and interception operations using only Japanese defense equipment. Japan's maritime equipment exports are also an area of interest, and last summer, the Philippine Navy expressed interest in acquiring used Abukuma-class destroyers currently operated by the Japan Maritime Self-Defense Force.

These movements indicate a significant turning point in Japan's security strategy. Japan, which has long upheld a policy of exclusively defensive and pacifist postures since the end of World War II, is taking on a more proactive role in response to changes in the regional security environment. The introduction of new equipment and enhanced practical training in the Iron Fist exercise, along with comprehensive security support to the Philippines, all demonstrate Japan's strengthening of cooperation with allied and partner countries and its ability to counter China's maritime expansion.

Looking ahead, the Japan-U.S. alliance is expected to continue to be the cornerstone of security in Northeast Asia. Meanwhile, bilateral cooperation with the Philippines, as well as the trilateral cooperation framework involving Japan, the U.S., and the Philippines, is anticipated to gain importance in countering attempts to change the status quo by force in the South China Sea. The signing of the RAA in 2024 and the ACSA in January 2026 have institutionalized the foundation for defense cooperation between the two countries. Through ongoing capability-building support and the expansion of defense equipment exports via the OSA program, the Philippines' maritime surveillance and defense capabilities are expected to steadily improve.

Japan's security strategy is evolving towards building a multilayered network with regional partners while maintaining the traditional Japan-U.S. alliance as its cornerstone. The two movements of the Iron Fist exercise and support for the Philippines are concrete manifestations of this new strategic approach, reflecting Japan's determination to maintain a free and open order in the Indo-Pacific region.