First Deployment of the Type 25 Anti-Ship Guided Missile by the Ground Self-Defense Force in Keen Sword 2026, Connecting Japan-U.S. Counterstrike Capabilities

From the Kumamoto Prefecture's Kengun Garrison, the vehicle-mounted Type 25 anti-ship guided missile is moving to the Oyanohara Training Area in the same prefecture. According to Kyodo News, the Ministry of Defense is coordinating to have this missile participate in the large-scale exercise "Keen Sword," which begins in October, for the first time. While live-fire exercises will not be conducted, there are plans to share target information with the U.S. military and confirm launch procedures.

From "Deployment" to "Connection"

The Type 25 is a new anti-ship guided missile assigned to the Japan Ground Self-Defense Force for maritime denial in the southwestern region, and it was deployed to Kengun in March 2026. Public information limits details on its range and warhead. Therefore, the focus this time is not on the numerical range but on whether the series of procedures for movement, target designation, and launch approval can be connected between Japan and the U.S.

Oyanohara is not a coastal launch site. Deploying missile units there is training to enhance survivability by combining training areas, roads, and communication bases, rather than assuming launches from fixed facilities. According to Kyodo News, the U.S. military and the Self-Defense Forces will share target information. This can be interpreted as an attempt to place the U.S. military's ISR (Intelligence, Surveillance, Reconnaissance) and the GSDF's coastal firepower on the same operational map.

What Keen Sword Will Test

The U.S. Naval Institute's USNI News reports that this Keen Sword will serve as a framework for practicing the defense of the southwestern islands of Japan. Considering the activities of the Chinese Navy and Coast Guard, this represents a shift from the idea of solely relying on Japan's Maritime Self-Defense Force escort ships to a concept that integrates GSDF missiles, Air Self-Defense Force aerial surveillance, and U.S. military intelligence and strike assets. The air activity data released by the Joint Staff Office of the Ministry of Defense on October 14 also indicates that air and maritime surveillance has become routine in the southwestern front.

However, in exercises without live-fire, the most challenging aspects remain. These include correctly identifying targets, how to exclude maritime traffic routes (SLOC) that include civilian vessels, and who will approve launches in times of crisis. While Japan-U.S. information sharing can be technically connected, it does not automate the speed of political decision-making.

Visualization of Deterrence and New Risks

For Japan, bringing the Type 25 into Keen Sword signifies a transition from declaring possession of counterstrike capabilities to integrating them into allied operational procedures. Even without live fire, if the transport of units and the connection of target information are made public, Japan's defense plans will appear more concrete to China and North Korea. On the other hand, as the transparency of the exercise increases, the likelihood of peacetime deployments provoking cautionary actions from adversaries also rises.

In my view, what is being questioned in this test is not the range of the Type 25. It is whether Japan and the U.S. can maintain a shared understanding of the same maritime area on a day without launches. The true weakness will likely remain not in the missile's performance specifications but in the command system that must expedite decision-making while avoiding misidentifications.

References

• Kyodo News, Japan SDF to incorporate long-range missiles into drill with U.S. in Oct.
• The Mainichi, Japan-US drill to start October to involve Japan's long-range missiles
• USNI News, U.S., Japanese Forces to Rehearse Defense of Japan's Southwest Islands
• Japan Joint Staff, East China Sea and Okinawa-area activity release, October 15, 2026