The New Dimension of the Japan-U.S. Alliance Demonstrated by Ground Force Cooperation

On February 11, a dialogue (Land Forces Dialogue) among the army chiefs of the U.S., Japan, Australia, and the Philippines was held in Tokyo. This meeting, attended by five generals including U.S. Indo-Pacific Army Commander General Ronald Clark and Japan Ground Self-Defense Force Chief of Staff General Masayoshi Arai, was ostensibly just a routine event called the "last LFD of 2025." However, to me, it appeared to symbolize a structural change in the Japan-U.S. alliance.

Having served for 25 years in the escort fleet, I must candidly say that I am surprised by the day when "the Ground Self-Defense Force would come to the forefront like this." For a long time, the core of the Japan-U.S. alliance has been the integrated operation of maritime and air forces, and the presence of the Ground Self-Defense Force was relatively weak. Now, it stands alongside the Philippine Army and the Australian Army, being referred to as a "key player in multilateral cooperation."

The Rise of the Army in Maritime Security

To understand this change, one must envision the geography of the southwestern islands. The island chain extending from Ishigaki Island to Yonaguni Island is crucial to countering China's maritime expansion, known as the "first island chain." What is required here is not the number of vessels, but ground-based anti-ship missile units that can be deployed on the islands. With the extended range (1000 km) of the Type 12 surface-to-ship guided missile, the Ground Self-Defense Force now possesses the capability to "blockade" the Miyako Strait, which is changing the very definition of maritime superiority.

The U.S. Army's promotion of Multi-Domain Operations should also be understood in this context. General Clark's mention of "enhancing interoperability" does not merely refer to standardizing communication protocols. It is an attempt to integrate the long-range precision firepower possessed by the Army with the information networks of the maritime and air forces, thereby establishing a new deterrent posture of "controlling the sea from the land."

The Variable of the Philippines

Another noteworthy aspect of this dialogue is the presence of Philippine Army Commander Lieutenant General Antonio Nafarete. His statement, "Geography divides us, but security unites us," reflects the reality that Manila is deepening its cooperation with Japan and the U.S. under pressure from China.

The U.S. Army's anti-ship missile units deployed in northern Luzon will control the Bashi Channel in the event of a crisis in Taiwan. For this "containment from the south" to function, close coordination with the Philippine Army is essential. The significance of the institutionalized dialogue platform of the LFD lies precisely here—gradually building command and control relationships for times of crisis during peacetime.

Discomfort as a Maritime Self-Defense Force Veteran

However, I have one concern. While the importance of ground forces is being emphasized, I worry that the "less visible advantages" of the Maritime Self-Defense Force, such as submarine capabilities and mine countermeasures, are being overlooked in budget allocation discussions.

It is commendable that support for strengthening the Self-Defense Forces reached 45.2% in a Cabinet Office public opinion survey, but if the content of that "strengthening" becomes overly focused on the Ground Self-Defense Force's island deployments, there is a risk that the anti-submarine warfare (ASW) expertise accumulated by the Maritime Self-Defense Force could be diluted. Considering the improved stealth of China's Type 039A submarines, this is a risk that cannot be ignored.

Has the "Center of Gravity" of the Alliance Shifted?

In conclusion, this LFD indicates that the Japan-U.S. alliance is evolving from a "maritime and air-centric" approach to "integrated operations across all domains." This, in itself, is a desirable direction. However, the true challenge lies in the essential yet understated question of how to optimize budget and personnel allocation among the Self-Defense Forces.

Both the Ground Self-Defense Force's island deployments, the Maritime Self-Defense Force's increase in submarines, and the Air Self-Defense Force's introduction of F-35s can each be justified. However, since defense spending cannot be increased infinitely, priorities must be set somewhere. My concern is whether that discussion is being adequately conducted behind the glamorous news of "the achievements of army cooperation."

"No single country, regardless of its strength, can defend this region alone. Multilateral cooperation is not a matter of convenience, but a strategic necessity." — Philippine Army Commander Lieutenant General Antonio Nafarete

This statement is correct. However, at the same time, under the name of "cooperation," countries must not neglect the development of their unique capabilities that they should focus on. In Japan's case, this includes anti-submarine capabilities and the defense of maritime shipping routes as a maritime nation. Policymakers should be cautious that the expansion of army cooperation does not become a smokescreen that obscures this core.