Wu Qiaoxi | 2026-04-21

Recent developments point to increasing security coordination and burden-sharing between the US, Japan and the Philippines in the face of ongoing Chinese encroachments.

Japan dispatched roughly 1,400 personnel to this year's US-Philippines Balikatan exercise, which began April 20. For the first time since World War II, Japanese combat troops are officially drilling on Philippine soil -- specifically in northern Luzon near Taiwan -- signaling a major leap in trilateral coordination.

Japan's participation in the exercise signals a "gradual shift towards a more networked security system in the Indo-Pacific," Joseph Kristanto, a research analyst at Singapore's S. Rajaratnam School of International Studies, told Radio Free Asia, pointing to a wider move toward minilateral cooperation.

Minilateralism is a diplomatic approach involving small groups of countries collaborating on specific, shared issues, as compared to broader, less agile multilateral organizations.

In its 2026 National Defense Strategy, the United States set out a concept of "strong denial defense."

Patrick M. Cronin, chair for Asia-Pacific security at the Hudson Institute, noted on War on the Rocks, a security analysis website, that the strategy's logic implies preventing a "rapid Taiwan fait accompli and constraining the People's Liberation Army's ability to establish sustained sea and air control inside the chain."

The strategy also says allies "must shoulder their fair share," Cronin said.

Shifting south

The same logic is also visible in the Philippines-US-Japan Multilateral Maritime Cooperative Activities, or MMCA.

In late February, the activities moved for the first time from the South China Sea to the Bashi Channel between the Philippines and Taiwan, expanding coordinated deployments on Taiwan's southern flank. The shift points to a broader effort by the United States and its allies to check China's maritime expansion and deter an attack on Taiwan, according to Asia Sentinel.

Mavulis Island, the MMCA exercise's main site, lies about 142 kilometers from Taiwan, while Japan's westernmost Yonaguni Island is about 110 kilometers away. These key nodes are being fortified, with Japan deploying electronic warfare units and missiles on Yonaguni, while the Philippines maintains a troop presence on Mavulis.

To bolster deterrence, Tokyo is aggressively developing "counterstrike capabilities," which include the March deployment of Type 25 land-based anti-ship missiles in Kumamoto and high-speed glide missiles in Shizuoka, effectively bringing Chinese targets within range.

Meanwhile, the United States is reinforcing its regional posture through joint exercises, including the placement of Navy Marine Expeditionary Ship Interdiction System (NMESIS) launchers in Okinawa and the northern Philippines, alongside the Typhon mid-range missile system.

Manila has bolstered this defensive line by stationing Indian-made BrahMos anti-ship missiles on Luzon. Collectively, these systems cover the waters surrounding Taiwan, supporting a broader deterrence posture.

Division of labor

Ou Si-Fu, deputy chief executive officer at Taiwan's Institute for National Defense and Security Research, told The Japan Times that the emerging posture amounts to "a division of labor for defending the first island chain."

According to Ou, the US could prevent Chinese warships from reaching the Pacific by working with Japan and the Philippines to secure the Miyako Strait and the Bashi Channel, respectively. This coordinated "sea denial" would allow Taiwan to concentrate its defense efforts on the Taiwan Strait.

Taiwan has signaled its readiness to join this strategic division of labor.

As reported by the Taipei Times, Foreign Minister Lin Chia-lung suggested that first island chain nations "divide and coordinate" their roles during a crisis and embrace "burden-sharing."

He stressed that regional partners need a clearer mutual understanding of their security duties. With Chinese military operations now spanning the Taiwan Strait to the East and South China Seas, Lin warned that Taiwan cannot be the "missing security link."

"China is trying to create a new normal, so I believe that first island chain nations should react together," Lin stated.

Sebastian Maslow, an associate professor at the University of Tokyo, told The Japan Times that Tokyo and Manila appear to be following a "coordinated deterrence strategy."

The recent intensification and institutionalization of their defense cooperation, he said, suggest the two countries have entered "a new stage" as both take on a larger role in regional security.