Joint Exercises of Japan, the United States, and the Philippines in the Bashi Channel: A New Phase in East Asian Security

On February 28, 2026, a joint exercise was conducted by the Japan Maritime Self-Defense Force, the U.S. Navy, and the Philippine Navy in the Bashi Channel. This exercise in the waters close to Taiwan symbolizes a new phase in military cooperation among allies in the Indo-Pacific region. This article analyzes the strategic significance of this exercise and the impact of the deepening Japan-U.S. alliance on regional security.

The Bashi Channel is a strategic chokepoint that separates Taiwan from the Philippines' Luzon Island. This area is an important sea lane connecting the Western Pacific and the South China Sea, and it is one of the main transit points for the People's Liberation Army Navy when deploying to the Pacific. According to a statement from the Philippine military, this exercise is intended to demonstrate a "sustained commitment to enhancing interoperability among partner forces, strengthening maritime security, and improving maritime situational awareness in the region."

The Japan Maritime Self-Defense Force participated with P-3C patrol aircraft, conducting training for anti-submarine warfare and maritime surveillance missions. Surface vessels from the U.S. Navy and the Philippine Navy also participated, aiming to enhance combined maritime operational capabilities. The exercise consisted of practical training, including live-fire drills, making it clear that it was not merely a goodwill exercise but aimed at verifying and improving operational capabilities in real combat scenarios.

The backdrop of this exercise is the rapidly changing security environment in East Asia. On February 18, 2026, the Extended Deterrence Dialogue (EDD) was held at the U.S. State Department. The U.S. side was co-chaired by the State Department and the Department of Defense, while the Japanese side was represented by the Ministry of Foreign Affairs and the Ministry of Defense. Participants included representatives from the Japan Joint Staff Office, the U.S. Joint Chiefs of Staff, U.S. Strategic Command, and U.S. Indo-Pacific Command, indicating that this dialogue is not merely a diplomatic formality but a substantive venue for military strategy coordination.

During the EDD, both countries reaffirmed the U.S. commitment to Japan's defense using all of its defense capabilities, including nuclear forces. Notably, the two countries discussed in detail China's "rapid, opaque, and destabilizing nuclear weapons buildup and testing." According to estimates from the U.S. Department of Defense, China's nuclear warhead stockpile could exceed 1,000 by 2030, representing a significant shift from its traditional minimum deterrence strategy.

In response to this nuclear buildup, Japan is significantly enhancing its conventional forces. Prime Minister Sanae Takaichi won a decisive victory in the February 2026 elections, gaining clear public support for strengthening defense capabilities. The Takaichi administration is accelerating the achievement of a defense budget equivalent to 2% of GDP and promoting the development of counterstrike capabilities (enemy base attack capabilities). According to an analysis by Bloomberg, this indicates "Japan's potential to take on greater responsibility for maintaining peace in Asia," and the U.S. should view this not as an excuse for alliance withdrawal but as an opportunity for alliance deepening.

The Japan Maritime Self-Defense Force is currently constructing two Aegis ships (ASEV) dedicated to ballistic missile defense. These vessels will be deployed in the Sea of Japan off the coast of the Korean Peninsula to address the ballistic missile threat from North Korea. Meanwhile, existing Aegis destroyers will be able to focus on maritime situational monitoring and sea lane defense in the East China Sea. This redeployment signifies that Japan is acquiring the capability to conduct both ballistic missile defense and conventional maritime operations simultaneously.

The threat from North Korea is also intensifying. On February 19, 2026, Kim Jong-un, the General Secretary of the Workers' Party of Korea, announced that he would set new military goals at the party congress scheduled for this month, showcasing advancements in missile development incorporating AI technology. North Korea continues to develop the solid-fuel ICBM "Hwasong-20," which is said to have the capability to reach all of the U.S. mainland. The U.S. and South Korea are scheduled to conduct large-scale joint military exercises, "Freedom Shield," from March 9 to 19, raising tensions on the Korean Peninsula.

The Bashi Channel exercise demonstrates the integrated response capabilities of the three countries to these complex threats. Japan and the Philippines have agreed to aim for the conclusion of a Reciprocal Access Agreement (RAA) in 2023, which, if realized, would significantly facilitate mutual visits and joint training between the Self-Defense Forces and the Philippine military. The U.S. already has individual alliance relationships with both countries, but institutionalizing trilateral cooperation would greatly enhance deterrence against China's maritime expansion.

Particularly important is the aspect of this exercise as a verification of operational capabilities in anticipation of a contingency in the Taiwan Strait. The Bashi Channel is located about 250 kilometers south of Taiwan and is a maritime area where U.S. and allied reinforcement forces are likely to pass during a Taiwan contingency. Chinese state media have criticized Japan's "acceleration of rightward shift" and have taken issue with Prime Minister Takaichi's statement that "in the event of a Taiwan crisis, Japan and the U.S. will jointly evacuate civilians." This indicates that Japan is clarifying its involvement in a Taiwan contingency.

Relations with South Korea are also a significant factor. South Korea is strengthening trilateral cooperation with Japan and the U.S. in response to the threat from North Korea, but it harbors complex feelings regarding Japan's military buildup. For many South Koreans, Japan's militarization is a greater concern than China's militarization, and Japan is viewed as a potential security threat alongside China. Nevertheless, as geopolitical analyst Peter Zeihan warns, with the possibility of a decline in U.S. security commitments, South Korea finds itself in a situation where it cannot avoid strengthening relations with Japan.

The strategic intentions of the U.S. are also noteworthy. The Trump administration has sought greater defense burdens from allies while emphasizing the importance of maintaining U.S. military presence in the Indo-Pacific region. During the Japan-U.S. EDD, the U.S. emphasized the need for multilateral strategic stability and arms control negotiations, indicating a willingness to engage in dialogue that includes China and Russia. This represents a dual approach combining military deterrence and diplomatic engagement.

The deepening of the Japan-U.S. alliance reflects a fundamental change in the East Asian security architecture. There is a transition from the hub-and-spoke alliance system of the Cold War era to a networked security system where Japan, South Korea, Australia, and the Philippines collaborate in a web-like manner. The Bashi Channel exercise exemplifies Japan's core role in this new system, symbolizing an expansion from mere bilateral cooperation between Japan and the U.S. to multilateral cooperation.

Future challenges include establishing a framework for information sharing among the three countries, developing common operational doctrines, and enhancing interoperable equipment systems. Additionally, establishing crisis management mechanisms to avoid unintended military conflicts with China is urgent. The EDD confirmed that Japan and the U.S. would conduct regular tabletop exercises, which will contribute to improving the alliance's responsiveness.

The joint exercise of Japan, the U.S., and the Philippines in the Bashi Channel clearly indicates that security cooperation in the Indo-Pacific region has entered a new phase. Facing complex threats such as China's nuclear buildup, North Korea's ballistic missile development, and tensions in the Taiwan Strait, Japan is deepening its alliance with the U.S. while strengthening multilateral cooperation with the Philippines, South Korea, and Australia. Under the Takaichi administration, Japan is significantly enhancing its defense capabilities and is no longer a country passively content with a protective role under the U.S., but is becoming an active player in regional security. Whether this change contributes to regional stability or creates new tensions will depend on future diplomatic efforts and military transparency.