US and Japan Open Keen Sword 27 With Anti-Ship Missiles on Yonaguni, 68 Miles From Taiwan

The US and Japan opened Keen Sword 27 on Monday, Oct. 19, one of the largest joint exercises the two allies have run. It is scheduled to run through Thursday, Oct. 29.

The Japanese Joint Staff Office says about 45,000 Japanese troops and 12,000 US service members are taking part. US Forces Japan's own statement put the American figure at 11,000.

Seven other countries are involved in parts of the drills: Australia, Canada, France, Germany, the Netherlands, New Zealand and the Philippines. The Joint Staff says France, Germany, the Netherlands, New Zealand and the Philippines are participating for the first time. South Korea and the UK are sending observers.

The hardware on Yonaguni

The focus is Japan's southwestern island chain. Yonaguni, Japan's westernmost island, sits about 110 km (68 miles) east of Taiwan.

The US Marine Corps is sending two systems there for the first time: NMESIS, a ground-based anti-ship missile launcher with a range of roughly 115 miles, and MADIS, a short-range air-defense system. Yonaguni's local government disclosed the deployment on a Friday, a day after the Okinawa Defense Bureau relayed deployment plans on Oct. 1.

Japan is showing off its new Type-25 land-to-ship missile, which has a range of about 1,000 km (620 miles) and can reach the Chinese mainland. The Ground Self-Defense Force began moving launchers from Camp Kengun in Kumamoto Prefecture on Oct. 18. It is the first time the system has left its home base. No test-firing is planned.

A US Army HIMARS rocket launcher is on nearby Ishigaki. The Army's Typhon mid-range launcher is also due to be moved to Okinawa mid-month. The US has not said whether it will be used in the exercise.

What the drills cover

The program includes amphibious landings, air and missile defense, mine sweeping, intelligence gathering, logistics and resupply, and casualty evacuation across several remote islands, including Tanegashima.

Defense News describes the design as a shift to ground-based, multi-island sea denial. Small, mobile units scatter across the islands instead of massing in a few big targets. That is the core of the Marine Corps' restructuring away from heavy armor toward small expeditionary forces that can seize and hold islands.

One gap stands out. The USS George Washington carrier strike group joined past iterations of the drill. This year it is in the Arabian Sea, sent in August to replace the USS Abraham Lincoln.

China is watching, and responding

On Monday, three PLA aircraft, two drones and a reconnaissance plane, flew through international airspace between Japanese islands into the Pacific and back toward mainland China, according to Japan's Joint Staff Office. Japan scrambled fighter jets.

A TB-001 reconnaissance and attack drone also passed between Yonaguni and Taiwan, flew northeast as far as waters off Amami Oshima, then turned back through the Miyako Strait. Japan also reported Chinese warships, including a supply ship that could support the carrier Liaoning.

Chinese military expert Song Zhongping told the Global Times earlier this month that the new US missile deployment on Yonaguni raises the risk of miscalculation between the US and China. He said Beijing may answer with its own drills in the area.

The friction predates the exercise. Prime Minister Sanae Takaichi said last year that Chinese military action against Taiwan could justify Japanese involvement. China's foreign ministry told Japan to "stop playing with fire" and urged Chinese citizens to avoid travel to Japan.

Tokyo and Taipei describe it differently

General Hiroaki Uchikura, chief of Japan's Joint Staff, denied that the exercises target a specific country. Japan's stated rationale is the growing tension from China, North Korea and Russia, and Japan considers China's rapidly growing military activity in and around Japan a threat.

Taiwan's Defense Minister Wellington Koo (顧立雄) read the drills more directly. He praised the inclusion of a Taiwan-related contingency scenario, saying peace and stability in the Taiwan Strait is a strong consensus in the global community and that democracies should share the responsibility.

The range numbers explain why Beijing is paying attention. NMESIS on Yonaguni can threaten ships in waters around Taiwan. The Type-25 can reach China's coastline. Neither is slated to fire at a live target in this exercise, but both are now on the map where Chinese planners can see them.

What comes next

The drills continue until Oct. 29. Whether Beijing follows through on the response Song described, a drill of its own near the area, is the open question. So is whether the Typhon launcher, due on Okinawa, takes part in any phase of Keen Sword 27.