Japan's Type-25 Long-Range Missile Demonstrates a Shift in Defense of the Southwestern Islands at Keen Sword 27 in 2026

During the Japan-U.S. joint integrated exercise Keen Sword 27, which began on October 19, the Japan Ground Self-Defense Force deployed the Type-25 anti-ship guided missile on Yonaguni Island for the first time. The missile has an estimated range of about 1,000 kilometers, allowing it to cover the Chinese mainland from an island approximately 110 kilometers away from Taiwan. Although no launch tests are scheduled, the significance of this deployment lies more in the implementation of dispersed positioning and joint operations during peacetime than in performance demonstration.

Specific Capabilities Demonstrated by the Exercise

According to the Associated Press, approximately 45,000 Self-Defense Force personnel and 12,000 U.S. military personnel are participating in Keen Sword 27, which will conduct training on island defense, amphibious landings, air and missile defense, mine clearance, logistics, and casualty evacuation until October 29. The U.S. Marine Corps' NMESIS anti-ship system and MADIS short-range air defense system have been deployed on Yonaguni Island, while HIMARS has been deployed on Ishigaki Island. For the Japan Maritime Self-Defense Force, the integration with the U.S. Navy, including the aircraft carrier USS Theodore Roosevelt, will serve as a litmus test for incorporating the firepower of ground forces into the maritime and aerial information network.

Separating Capabilities and Intentions

The Japanese side explains that this exercise is not targeting any specific country. However, the operational deployment of Type-25, NMESIS, and HIMARS on the same island chain represents the construction of a denial capability that deters enemy vessels and landing forces from approaching. The political message to China is clear, but actual deterrence is not determined solely by the missile's range. Without updates on target information, post-launch repositioning, and the survivability of supply ships and runways, the figure of 1,000 kilometers remains a theoretical value against fixed targets.

Additionally, France, Germany, the Netherlands, New Zealand, and the Philippines participated in some training for the first time. This indicates a transition from bilateral defense between Japan and the U.S. to a multilateral network protecting SLOCs (Sea Lines of Communication). However, as the number of participating countries increases, standardizing rules of engagement, communication security, and logistics procedures becomes more challenging. In the Pacific Vanguard 26 exercise announced by the U.S. Navy, interoperability among P-1 patrol aircraft, submarines, and vessels from various countries was emphasized, but there remains a gap in peacetime coordination and decision-making speed during emergencies.

Overlooked Weaknesses

The challenges of defending the Southwestern Islands are believed to have shifted from a lack of range to operational sustainability. The evacuation of island residents, resupply of fuel and ammunition, and command succession during communication disruptions are aspects that may not be visible unless actual stress is placed on them during the exercise. In the author's view, the true value of Keen Sword 27 lies not in the existence of new missiles but in how long dispersed units can function before being attacked. The next weakness of the Japan-U.S. alliance is not firepower but logistics connecting the islands.

References

• Associated Press / U.S. News, October 19, 2026
• U.S. Navy, “U.S., Allied Forces Join for Exercise Pacific Vanguard 2026,” August 31, 2026
• Ministry of Defense Joint Staff Office, “Activities of Chinese Aircraft in the East China Sea and Pacific,” October 23, 2026