US-Japan Keen Sword to put new anti-ship missiles near Taiwan

The United States and Japan will use the upcoming Keen Sword bilateral exercise to move new land-based anti-ship missile systems onto Japanese islands close to Taiwan, Central News Agency reported on Friday citing Japanese media. The field training exercise is scheduled to run for 11 days from 19 October across Japan and surrounding waters and airspace.

According to NHK reporting carried by CNA and SBS, U.S. forces plan to deploy the Navy Marine Expeditionary Ship Interdiction System, or NMESIS, to Yonaguni Island for the first time during the drill. Yonaguni lies about 107 kilometres from Taiwan and has hosted a Ground Self-Defense Force garrison since 2016.

NMESIS mounts anti-ship missiles with ranges above 180 kilometres on a remotely operated unmanned vehicle and is a core weapon for U.S. Marine littoral units designed to operate from islands with short response times. Japanese Ground Self-Defense Force land-based anti-ship missiles with ranges of more than 100 kilometres are also expected to appear on Yonaguni for the first time in the exercise, CNA said.

SBS English, also citing NHK, described Keen Sword as a live manoeuvre exercise focused on Japan's defence and said deploying the newest U.S. and Japanese surface-to-ship missiles at Japan's westernmost point is intended to strengthen deterrence with China in mind. The same report noted local opposition concerns around continued missile deployments.

Kyodo News reported earlier that the Ground Self-Defense Force will incorporate its Type-25 long-range surface-to-ship guided missile into the same October Japan-U.S. drill for the first time in a large-scale exercise. Defence Ministry officials said the Type-25 events would take place at Camp Kengun in Kumamoto Prefecture and the Onohara Maneuver Area straddling Nagasaki and Saga prefectures.

Kyodo said about 45,000 Self-Defense Force personnel will take part and that Keen Sword from 19 to 29 October will not include actual firing of the Type-25 missiles. Australia, Canada, France, Germany and other partners are also expected to send forces to portions of the exercise, according to CNA.

Separately, the Okinawa Times reported on Friday that U.S. forces plan to bring NMESIS together with the Marine Air Defense Integrated System and HIMARS rocket artillery to Ishigaki City for Keen Sword, describing a simultaneous three-system U.S. deployment there as a first. That account places additional U.S. systems on another Yaeyama island during the same exercise window.

Taken together, the Japanese reporting points to a southwest-islands focus inside Keen Sword that layers U.S. littoral anti-ship and air-defence systems with Japanese land-based anti-ship missiles. Officials have linked the posture to deterrence against China while acknowledging that denser missile presence can stir local political pushback.

Yonaguni town authorities, CNA noted via local Ryukyu Asahi Broadcasting coverage, recently approved leasing about 28 hectares of municipal land around the Ground Self-Defense Force camp to the defence bureau for security use. How those parcels relate to exercise logistics was not detailed in the Friday dispatches.

Keen Sword remains a recurring Japan-U.S. bilateral series rather than a Taiwan-hosted drill, yet the geography of Yonaguni and Ishigaki makes the missile movements strategically relevant to Taiwan's eastern approaches. Further official briefings may clarify which systems stay after the 11-day exercise ends.

This report was produced through TaiwanDefence’s automated publishing system and includes links to its supporting sources.