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

Key Chapter Title List

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

Document Introduction

This report provides an in-depth analysis of the rapidly deepening defense cooperation between Japan and the Philippines since 2016 within the context of the "Free and Open Indo-Pacific" strategic initiative. The study posits that against the macro backdrop of intensifying U.S.-China strategic competition, the outbreak of the war in Ukraine, and the ongoing tensions in the South China Sea, Japan-Philippines relations are transcending traditional bilateral cooperation and gradually evolving into a "quasi-alliance" form. This relationship is not based on a formal alliance treaty but is rooted in the reality that the two countries share a common ally (the United States), perceive a common security threat (particularly pointing to China's maritime activities), and engage in substantive and symbolic defense cooperation.

The report first outlines the strategic positioning of Japan's FOIP initiative in Southeast Asia, particularly towards the Philippines. Since Japan proposed the FOIP concept in 2016 and the "Vientiane Vision" defense cooperation guidelines for ASEAN, Tokyo has regarded defense cooperation with Manila as a key component in maintaining maritime order stability in the Indo-Pacific region and balancing China's influence. The Philippines' geographical location and its South China Sea sovereignty disputes with China make it a priority partner for Japan in implementing this strategy. The report notes that although the Duterte administration initially displayed a posture of distancing from the U.S. and easing relations with China, it still sought to enhance maritime security cooperation with Japan during its tenure. Following the inauguration of the Marcos Jr. administration, while strengthening the U.S.-Philippines alliance, the Philippines has also actively expanded defense collaboration with U.S. allies such as Japan and Australia, indicating a trend of evolution from a U.S.-led "hub-and-spokes" alliance system towards a "networked" architecture.

The factors driving the deepening of Japan-Philippines defense cooperation are multi-layered. The primary factor is the change in the macro international order, particularly the intensification of U.S.-China strategic competition and the war in Ukraine, which has exacerbated international bloc formation, prompting Japan, the U.S., and their allies to strengthen coordination, while also raising concerns in the Philippines about the reliability of future U.S. regional commitments. Secondly, Japan's regional leadership and FOIP strategy serve as external drivers for promoting cooperation with the Philippines, aiming to counterbalance China's expansion in the South China Sea by supporting ASEAN countries, including the Philippines, in enhancing their resilience. Thirdly, the escalation of the South China Sea disputes directly propels cooperation between the two countries in areas such as maritime domain awareness, maritime law enforcement capacity building, and upholding the rules-based international order. Fourthly, Japan is actively promoting multilateral cooperation under the "U.S.-Japan + X" model, with trilateral Japan-U.S.-Philippines and even multilateral defense coordination mechanisms involving Australia and South Korea taking shape. Fifthly, uncertainties regarding future U.S. regional engagement prompt Japan to strengthen ties with like-minded countries such as the Philippines for strategic preparedness. The report also notes that China has shown high vigilance towards Japan-Philippines defense cooperation, analyzing its strategic intentions and expressing concerns through channels such as official media.

The core section of the report examines in detail the specific progress in Japan-Philippines defense cooperation since 2016. This includes strategic alignment based on the "Vientiane Vision"; frequent high-level exchanges and institutionalized dialogues (such as the first "2+2" Foreign and Defense Ministerial Meeting); breakthrough developments in defense equipment and technology transfer (e.g., the transfer of TC-90 training aircraft, UH-1H helicopter parts, air surveillance radar systems, and the provision of coastal surveillance radar systems under Japan's "Official Security Assistance" framework); and increasingly frequent bilateral and multilateral joint exercises and capacity-building activities (covering areas such as anti-submarine warfare, humanitarian assistance and disaster relief, and amphibious operations). This cooperation has transcended the bilateral scope and is increasingly integrated into U.S.-led multilateral exercise networks.

Based on the above analysis, the report proposes the conceptual framework of a "quasi-alliance" to describe the current state of Japan-Philippines relations. Drawing on and modifying Victor D. Cha's alliance theory, the report defines a "quasi-alliance" as "a de facto alliance characterized by substantive and symbolic defense cooperation between countries that share a common ally and perceive a common threat." Japan-Philippines relations fit this definition: both countries share the U.S. as a key ally, view China's actions in the East and South China Seas as major security concerns, and have engaged in deep and increasingly institutionalized defense collaboration. The report anticipates that against the backdrop of ongoing U.S.-China and Japan-China competition and the difficulty in easing South China Sea tensions, Japan-Philippines defense cooperation is expected to continue advancing steadily. The potential conclusion of the Reciprocal Access Agreement currently under negotiation would further institutionalize this quasi-alliance relationship.

The conclusion summarizes the academic and policy significance of this study. The report fills a gap in systematic research on Japan-Philippines defense cooperation within Japanese academia and provides a "quasi-alliance" theoretical perspective for analyzing the evolution of bilateral relations. For Japan, the quasi-alliance with the Philippines is not only a crucial part of strengthening its Indo-Pacific security network and responding to the "most severe" security environment since the war, but also offers a model for future effective defense cooperation with countries lacking sufficient self-defense capabilities. Japan should continue to deepen strategic collaboration with the Philippines from a position of leadership rather than condescension, while accumulating overseas operational experience to better achieve its regional security objectives.