US-Japan Launch Largest Keen Sword Drills with Anti-Ship Missiles Deployed to Islands Near Taiwan

The US and Japan began their biennial Keen Sword 27 exercise on October 19, 2026, one of the largest joint military drills between the allies, running through October 29. The exercise emphasizes defense of Japan's southwestern island chain, including Yonaguni—just 110 km east of Taiwan—and involves approximately 45,000 Japanese Self-Defense Forces personnel, 11,000-12,000 US troops, and forces from Australia, Canada, France, Germany, the Netherlands, New Zealand, and the Philippines, with observers from South Korea and the UK.

Key firsts include the US Marine Corps deploying the Navy-Marine Expeditionary Ship Interdiction System (NMESIS) anti-ship missiles and Marine Air Defense Integrated System (MADIS) to Yonaguni for the first time, alongside Japan's initial deployment of its longer-range Type-25 surface-to-ship missiles (range ~1,000 km) outside their permanent base. A US HIMARS rocket system was also positioned on nearby Ishigaki. These deployments enable coverage of waters around eastern Taiwan and potentially reach parts of mainland China.

Official Japanese Joint Staff documents and statements from US Forces Japan confirm the scale and focus on integrated air/missile defense, anti-ship operations, and multi-domain training. Chinese military vessels, aircraft, and drones have been observed tracking the drills, according to Japan's defense ministry and reports from the South China Morning Post. The exercises occur amid heightened regional tensions, with prior reporting from Bloomberg and others noting pre-exercise planning for the Yonaguni deployments.