Japan and the U.S. Defense Ministers Confirm the Importance of Denial Defense in the First Island Chain: The Reality of Logistics Highlighted by the 2026 Exercises

On October 28, Defense Minister Shinjiro Koizumi of Japan and U.S. Secretary of Defense Lloyd Austin met in the Philippines and confirmed the importance of achieving "effective denial defense" in the First Island Chain. This meeting coincided with the conclusion of the Japan-U.S. joint integrated exercise "Keen Sword 27" on the following day, and it is more than just a joint statement. The exercise, which involved 45,000 Self-Defense Force personnel and 12,000 U.S. military personnel, indicates that operations in the southwestern islands have entered a new phase.

What the Dispersed Deployment of Equipment Means

On Yonaguni Island, located about 110 kilometers from Taiwan, the Japan Maritime Self-Defense Force has deployed island defense capabilities reminiscent of the long-range capabilities of the Type 12 surface-to-ship guided missile, along with the U.S. Marine Corps' NMESIS and MADIS, as well as HIMARS from Ishigaki Island. According to the Taipei Times, the exercise included not only amphibious operations and air and missile defense but also intelligence gathering, logistics, and casualty evacuation. This structure tests not just the ability to "fire," but the information connectivity from detection to firing, and whether ammunition can be continuously delivered to isolated islands.

Practical Weaknesses of Denial Defense

However, placing missiles on an island and ensuring they function over the course of weeks during a crisis are two different issues. Runways, ports, fuel, and satellite communications are vulnerable to attacks and disruptions, and the operation of supply ships and transport aircraft is constrained by weather and civilian infrastructure. The "denial" concept indicated by the U.S. Department of Defense makes it difficult for the Chinese military to approach, but the reliability of deterrence depends not on the numbers of range but on training to switch to dispersed operations for affected bases.

Furthermore, Minister Koizumi's explanation of the revision of security-related documents by the end of the year signifies that Japan and the U.S. have entered a phase of refining command relationships and political decision-making in emergencies, not just equipment updates. The response to the incident involving U.S. Marines in Okinawa, reported by The Straits Times, also illustrates that the friction between the military aspects of the alliance and the society that hosts the bases cannot be separated.

Next Challenges for the Alliance

The core of the defense ministerial talks lies not in the number of missiles but in confirming the willingness to jointly maintain the First Island Chain.

In my view, the lesson from Keen Sword 27 is not a simple conclusion that "Japan and the U.S. should have more firepower." What Japan should take on is the endurance that includes logistics, repairs, and civilian evacuation in the island regions. The true blind spot is not China's capabilities but whether the military plans of the alliance and Japan's political decision-making can operate at the same pace when a crisis prolongs.

Reference Information

• Taipei Times, "Japan, US launch drills focusing on islands near Taiwan," October 21, 2026
• The Straits Times, "Japan, US defence chiefs agree to boost deterrence amid China clout," October 28, 2026
• Japan Joint Staff Office announcement "FY 2026 Japan-U.S. Joint Integrated Exercise (Keen Sword 27)"