Japan sending combat troops to participate in upcoming exercises in the Philippines is a signal of a shift towards a more networked, multi-layered security structure in the South China Sea that is still anchored by the United States, analysts in the region told Radio Free Asia.
At least 1,000 Japanese troops are set to take part in April’s Balikatan exercises alongside forces from the Philippines and the U.S., in a move that carries historical weight but is increasingly viewed through the lens of evolving regional security dynamics.
The South China Sea has become one of Asia’s most contested strategic flashpoints in recent years, with overlapping territorial claims and frequent maritime confrontations. China’s use of so-called “grey zone” tactics – coercive actions that fall short of open conflict – has added pressure on smaller Southeast Asian states, pushing them to strengthen external security ties.
“Japan’s involvement in Balikatan and the wider move toward minilateral cooperation do suggest 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 RFA.
That shift is visible in how exercises themselves have evolved. Balikatan began in the 1990s as a relatively small-scale bilateral training exercise focused on counterinsurgency and disaster response.
But now it involves thousands of troops and it simulates large scale conflict scenarios, including amphibious operations, missile defense and critical infrastructure protection.
The exercise has also grown beyond its original U.S.-Philippines format.
In recent iterations, countries such as Japan and Australia have taken on more active roles, with Japan participating as an observer since 2012, and last year sending a single frigate and about 150 non-combat personnel.
The increased participation from multiple countries reflects a broader push to build interoperability among like-minded partners.
New domains such as cyber, space and information warfare have been incorporated, mirroring how regional planners now view potential conflict as spanning multiple fronts rather than being confined to conventional naval or territorial disputes.
Regional anxiety
Still, the emergence of these overlapping partnerships does not signal a post-American security order.
“This does not replace the traditional U.S.-led ‘hub-and-spoke’ system. Instead, it adds another layer to it,” Kristanto said.
The “hub-and-spoke” model – under which the U.S. maintains bilateral alliances with countries such as Japan, South Korea and the Philippines – has underpinned Asia’s security architecture for decades.
What is changing, according to experts, is the growing number of links between those “spokes,” as countries deepen cooperation with each other through joint exercises, intelligence sharing and defense agreements.
That layering is partly driven by uncertainty over Washington’s long-term bandwidth in the region, even as it remains the central security guarantor.
U.S. security commitments in Europe and the Middle East, alongside domestic political debates over defence spending, have prompted some regional governments to hedge by strengthening ties with other partners.
“The latest move comes amid rising regional anxiety about U.S. defense commitment and capacity in the Indo-Pacific region,” William Yang, a Northeast Asia analyst at the International Crisis Group, told RFA.
Countries such as Japan are therefore stepping up – not to replace the United States, but to reinforce deterrence and share the burden.
“These moves are certainly not intended to take over the central role that the U.S. takes in terms of regional deterrence,” Yang added.
In practical terms, that shift is translating into deeper operational integration. Exercises are no longer just about presence or signalling, but about testing how forces coordinate across multiple domains and contingencies, Yang said.
“Having more partners such as Japan involved could lead to real operational changes over time, not just symbolic ones,” Kristanto said, noting that drills are becoming “more integrated and more multilateral.”
Japan’s participation also builds on a steady expansion of defence ties with the Philippines, including joint maritime exercises and the provision of coastal radar systems.
These capabilities are designed to improve Manila’s ability to monitor its waters, particularly in contested areas where Chinese vessels have maintained a persistent presence.
“Japan’s more proactive participation in bilateral military drills and patrols as well as multilateral military exercises could help strengthen regional coordination and capacity building in areas such as countering Chinese gray zone operations and strengthening Southeast Asian states’ maritime domain awareness,” Yang explained.
‘More connected network’
What would be the first deployment of Japanese combat troops in the Philippines since World War II–when Imperial Japan occupied what was then a U.S. territory–is not lost in public opinion.
Protesters in the Philippines say Tokyo has unresolved wartime grievances with Manila, while protesters in Japan fear the move is part of a larger trend of increased militarism counter to the spirit of their pacifist constitution.
Experts told RFA that Japan’s participation reflects a broader effort to connect security arrangements across the Indo-Pacific into a more cohesive framework.
For Shen Ming-Shih, a research fellow at Taiwan’s Institute for National Defense and Security Research, this is most clearly seen along the so-called First Island Chain – a strategic arc stretching from Japan through Taiwan to the Philippines.
“Japan now participates with ground troops in addition to warships this year, indicating a rising possibility of joint U.S.-Japan-Philippines responses to South China Sea conflicts,” Shen told RFA, pointing to “a growing likelihood of alliance-based joint operations and defense industry cooperation.”
Although no formal multilateral alliance exists, these overlapping partnerships are beginning to resemble a more connected network.
“Through the alliances between the U.S. and these countries, a network of alliances centered on the U.S. will be formed,” Shen said.
For Beijing, that growing coordination is likely to be viewed with concern, particularly as exercises become more frequent and more operationally substantive.
“The expansion of these minilateral groupings will likely be viewed with concern,” Kristanto said, warning that it “does increase the risk of misperception and sharper responses in contested areas.”
Edited by Eugene Whong.