Japan's Type 25 Missile to Participate for the First Time in the 2026 Riken Exercise, Connecting Japan-U.S. Counterattack Capabilities

The Type 25 surface-to-ship guided missile, which has been deployed at the Ground Self-Defense Force's Kengun Base in Kumamoto City since March, will participate for the first time in the Japan-U.S. joint training exercise "Riken 26," held from October 19 to 29. Approximately 45,000 Self-Defense Force personnel will participate, utilizing a wide area that includes six domestic airports and ten ports. While live fire will not be conducted, this is not merely a demonstration. It indicates that Japan's stand-off defense has progressed to the stage of incorporating units, munitions, and command communications into actual movement plans.

Significance of Deploying 1,000-Kilometer-Class Missiles in the Exercise

The Type 25 is said to have a range of approximately 1,000 kilometers, covering a wider maritime area than conventional coastal defense missiles. The Ministry of Defense positions it as equipment to be used for counterattack capabilities in the event of an emergency. What is crucial is not just the range figure itself, but how to relocate the launchers, from which sensors to receive target information, and how to connect with U.S. air and naval forces.

Kengun is located in central Kyushu, far from the southwestern islands. If units can be dispersed via ports and airports from here, the risk of the launch site being identified early by the adversary can be reduced. On the other hand, if the long-range missiles have slow target identification and engagement approval speeds, they will not serve as a deterrent. In this training, which does not involve live fire, the focus will rather be on testing this "pre-launch" connection.

Connection with the Maritime Self-Defense Force's Modified Tomahawk Vessels

The Japan Maritime Self-Defense Force has returned Aegis ships modified to launch U.S.-made Tomahawk cruise missiles to Sasebo at the end of August. While the Ground Self-Defense Force's Type 25 and the Maritime Self-Defense Force's Tomahawk are not the same weapon, they require a common circuit for target information, political approval, and joint operations with U.S. forces. For the Japan-U.S. alliance, this represents a shift from the traditional division of labor, where the U.S. military handles long-range strikes and the Self-Defense Forces focus on air defense and anti-ship warfare, to a system that operates multiple launch means on the same operational map.

However, large-scale training that utilizes ports and airports also exposes dependence on civilian infrastructure. If there is any delay in fuel, transportation, communication, or explanations to residents, the 1,000-kilometer range will revert to being just a number on paper. In the author's view, the true test of Riken 26 is not the missile itself, but how quickly the connection can be made from peacetime administrative procedures to wartime engagement decisions. Japan's counterattack capability may be constrained more by the slowness of decision-making than by the number of launchers.

Sources

• Kyodo News "Japan SDF to incorporate long-range missiles into drill with U.S. in Oct."
• NHK WORLD-JAPAN "Japan, US set for large-scale field training exercise"