What Japan's Self-Defense Forces' Participation in Balikatan Exercises Means: Extending Deterrence from the Nansei Islands to the Philippine Sea

The Japan Self-Defense Forces will dispatch approximately 1,400 personnel to the U.S.-Philippines joint military exercise "Balikatan," which will be held from April 20 to May 8, 2026. This marks Japan's largest-ever troop deployment to participate in the exercise, making it the third-largest troop contributor after the United States and the Philippines. The deployment will include multiple escort ships, aircraft, and the Type 88 Surface-to-Ship Guided Missile System, clearly demonstrating Tokyo's intention to engage in the security of the entire First Island Chain beyond the context of defending the southwestern islands.

The Balikatan exercise has been conducted annually since 1991 as a large-scale joint exercise between the U.S. and the Philippines, and in recent years, it has been positioned as a deterrent against China's unilateral claims in the South China Sea. In the 2024 exercise, France and Australia participated as observers, but Japan's inclusion this year as a full participant, including combat units, signifies an expansion of the exercise's geographical and strategic scope from the East China Sea to the South China Sea. According to the information released by the Joint Staff Office of the Self-Defense Forces, Japan's participation will cover all domains: air, land, sea, and cyberspace. This includes demonstrations of capabilities deemed essential in the event of a crisis in Taiwan, such as maritime strike operations, live-fire training against landings, and integrated air and missile defense.

Particularly noteworthy is the deployment of the Type 88 Surface-to-Ship Guided Missile. This coastal defense missile system is the predecessor to the Type 12 Surface-to-Ship Guided Missile that Japan is advancing to deploy in the southwestern islands and forms the core of its coastal denial capabilities against ships. Operating this system around Luzon in the Philippines will serve as a demonstration of substantial blockade capabilities against Chinese naval vessels passing through the Bashi Channel. The Bashi Channel is an international waterway located between the southern tip of Taiwan and Luzon in the Philippines, which the People's Liberation Army Navy considers a critical route for its expansion into the western Pacific. Conducting anti-ship missile operations in this maritime area during the exercise carries a strategic message beyond mere capability demonstration in peacetime.

As analysts point out, this participation indicates Japan's "priorities." In the national security strategy formulated in 2022, Japan explicitly stated that the stability of the Taiwan Strait is "extremely important for Japan's security." Since then, Japan has set a goal to raise defense spending to 2% of its GDP and has accelerated the acquisition of stand-off weapons. However, participation in the Balikatan exercise signifies not just a strengthening of budgetary aspects but also the actual construction of expeditionary deployment capabilities and multilateral operability. The deployment of 1,400 personnel from the Self-Defense Forces to the Philippines and conducting joint operations with the U.S. and Philippine militaries symbolizes a shift from a defensive context of southwestern island defense to a proactive deterrence context utilizing alliance networks.

Beijing's response to this move is likely to be predictable. The Chinese Foreign Ministry has already shown a critical stance towards Japan's participation, using the cliché of "intervention by external forces." The Eastern Theater Command and Southern Theater Command of the People's Liberation Army may increase deliberate military actions during the Balikatan exercise period. An increase in the frequency of sorties by fighter jets and bombers around Taiwan and in the South China Sea, as well as enhanced naval vessel patrols, is anticipated. In 2025, the U.S. Indo-Pacific Command warned that the frequency of China's "invasion rehearsals" is increasing, and this exercise is likely to further accelerate that trend.

At the same time, the deepening of Japan-Philippines security cooperation should not be overlooked. Under the Japan-Philippines Defense Equipment and Technology Transfer Agreement signed in 2016, Japan has provided the Philippines with surveillance radar systems, and discussions are currently underway to support the development of air defense missile capabilities. As the modernization of the Philippine military has been slow, Japan's expansion of support in terms of equipment and training directly contributes to the establishment of a multilateral deterrent posture in the South China Sea. For Manila, the presence of an additional security partner like Japan, in addition to the United States, enhances its negotiating power in disputes with China.

This matter is also noteworthy in relation to the situation on the Korean Peninsula. Reports this week indicated that the South Korean-made surface-to-air missile "Cheongung-II" (M-SAM) has been deployed in combat in the United Arab Emirates, achieving a 96.7% interception success rate against Iranian drones and ballistic missiles. The situation where two U.S. allies in East Asia are advancing deterrence capabilities in different security contexts suggests an overall strengthening of the U.S. alliance network. However, security cooperation between Japan and South Korea remains constrained by historical issues, and there are currently no prospects for South Korea to participate in the Balikatan exercise.

Japan's participation in the Balikatan exercise should be understood as a strategic turning point that goes beyond a single exercise. The institutionalization of trilateral cooperation among Japan, the U.S., and the Philippines along the First Island Chain, the demonstration of the Self-Defense Forces' expeditionary deployment capabilities, and the communication of a complex deterrent message to China—all of these indicate that the shift in the security strategy in 2022 has been translated into concrete actions. The reactions from China during the exercise period, as well as the progress of Japan-Philippines defense cooperation afterward, will likely serve as important indicators that influence the future security environment in East Asia.