Japan-Philippines Defense Cooperation under the Free and Open Indo-Pacific Initiative: The Emergence of a Quasi-Alliance Relationship as a New Chapter in Japan-Philippines Relations

Key Chapter Title List

1. Introduction: Research Background and Problem Statement
2. 1. Japan-Philippines Defense Cooperation under the FOIP Initiative: Progress in Bilateral Relations
3. 2. Factors Driving Japan-Philippines Defense Cooperation: Changes in International and Regional Dynamics and China's Response
4. 3. The Evolution of Japan-Philippines Defense Cooperation: The FOIP Initiative and Vientiane Vision since 2016
5. 3. (1) Vientiane Vision and the FOIP Initiative
6. 3. (2) Summit and Ministerial Meetings
7. 3. (3) Defense Equipment and Technology Transfer Cooperation
8. 3. (4) Joint Exercises, Defense Exchanges, and Capacity Building Assistance
9. 4. The Emergence of a Quasi-Alliance between Japan and the Philippines: Future Prospects for Bilateral Relations
10. Conclusion: Research Summary and Policy Implications

Document Introduction

This study aims to delve into the evolution, driving factors, and shaping of the nature of bilateral relations in Japan-Philippines defense cooperation under the framework of the "Free and Open Indo-Pacific" initiative. The research background is rooted in macro-structural factors such as the intensification of U.S.-China strategic competition, the outbreak of the Ukraine war, and the ongoing tensions in the South China Sea disputes. These factors collectively prompt Japan to increase its security engagement in the Indo-Pacific region and view the Philippines as a key strategic partner. Although existing literature focuses more on the Japan-U.S. alliance and Japan's relations with other allies, systematic research on Japan-Philippines defense cooperation is relatively scarce. This report fills this academic gap.

The report has a clear structure. First, it outlines the overall progress of Japan's defense cooperation with Southeast Asian countries, particularly the Philippines, under the FOIP initiative. Second, it provides a detailed analysis of the five major factors driving the deepening of Japan-Philippines defense cooperation: including the polarization of the international order due to U.S.-China competition and the Ukraine war, Japan's demonstrated regional leadership through FOIP, the escalation of the South China Sea issue, Japan's efforts to promote the "Japan-U.S.+X" multilateral cooperation model, and Japan's preparations to address potential future uncertainties in U.S. regional engagement. The report also pays attention to China's vigilance and response to the development of Japan-Philippines relations, noting that Beijing increasingly views it as a potential erosion of its regional influence.

The core empirical section of the report systematically reviews the specific trajectory of Japan-Philippines defense cooperation since 2016. This includes the proposal and updating of the "Vientiane Vision" and its 2.0 version as the strategic foundation for cooperation; frequent bilateral high-level summits and institutionalized dialogues such as the "2+2" meetings; milestone projects in defense equipment and technology transfer like the TC-90 trainer aircraft, early warning and control radar systems, and large patrol vessels; as well as increasingly frequent bilateral and multilateral joint exercises, defense exchanges, and capacity-building assistance. The content of this cooperation is extensive, ranging from maritime security and humanitarian assistance to intelligence sharing and joint training, indicating that cooperation has moved beyond the symbolic level into a substantive operational phase.

Based on the above analysis, the report introduces and develops the conceptual framework of a "quasi-alliance" to define the current Japan-Philippines relationship. Drawing on and revising Victor D. Cha's theory, this study defines a "quasi-alliance" as "a de facto alliance characterized by substantive and symbolic defense cooperation between states that share a common ally and perceive a common threat." Japan and the Philippines share the United States as a core ally and jointly view China's maritime activities as a security threat. This structural environment has driven the strengthening of their partnership, giving it the characteristics of a "quasi-alliance." The report predicts that this bilateral trajectory is expected to continue deepening under the existing international and regional dynamics.

This study not only has academic value by revealing the neglected defense dimension in Japan-Philippines relations but also provides important implications for Japan's security policy. The report argues that the successful Japan-Philippines defense cooperation provides a replicable model for Japan's future management of relations with countries that have insufficient self-defense capabilities. Through equipment transfers, joint training, and potential future institutional arrangements such as a Reciprocal Access Agreement (RAA), Japan can not only enhance the Philippines' defense capabilities to help maintain regional maritime order stability but also accumulate valuable overseas operational experience, further solidifying its role as a key security partner in the Indo-Pacific. Therefore, Japan should effectively utilize its cooperation experience with the Philippines to refine its defense cooperation strategy with more like-minded countries in an increasingly uncertain international environment.