US and Japan Deploy Anti-Ship Missiles to Yonaguni in Keen Sword Drills

US Marines positioned the Navy-Marine Expeditionary Ship Interdiction System on Yonaguni while Japan emplaced its first Type-12 land-to-ship battery there. The systems cover sea lanes east of Taiwan and reach the Chinese mainland. The exercise also placed a HIMARS launcher on Ishigaki, 150 miles from Taiwan. Forty-five thousand Japanese personnel, eleven thousand US troops, and contingents from Australia, Canada, France, Germany, the Netherlands, New Zealand, and the Philippines are participating.

The deployments alter the cost calculation for any Chinese naval movement through the Miyako Strait and Bashi Channel. Japan gains extended surveillance and strike reach from its own territory; the US gains forward positioning without new permanent bases. China records the placement of 115-mile and 620-mile range weapons on islands it claims as part of its first island chain and has signaled intent to increase coast-guard and naval activity east of Taiwan.

Primary records show US Forces Japan stating the drill improves interoperability. Japanese Ministry of Defense documents list the Type-12 introduction as routine modernization. Chinese Ministry of National Defense statements describe the activity as external interference in Taiwan affairs. No side has published rules of engagement or escalation thresholds for the current exercise window.

Next steps hinge on whether Japan and the Philippines conclude their maritime boundary talks and whether additional US rotational forces remain after Keen Sword concludes in early November.