US plans first NMESIS deployment on Japan’s Yonaguni island

The United States plans to deploy its NMESIS anti-ship missile system on Japan’s Yonaguni island for the first time during the Keen Sword exercises from Oct. 19 to 29, according to reports published on Oct. 2 and 3. Yonaguni, in Okinawa Prefecture, lies about 110km from Taiwan.¹²

A new deployment near Taiwan

The South China Morning Post described the Navy-Marine Expeditionary Ship Interdiction System, or NMESIS, as a ground-based, uncrewed US missile platform. The Japan Times reported that the system has a range of about 115 miles and could strike ships operating around Taiwan.¹²

Yonaguni is Japan’s westernmost island and sits about 110km from Taiwan’s eastern coast, according to the South China Morning Post. The Japan Times described it as the closest Japanese territory to Taiwan. The planned deployment would bring NMESIS nearer to Taiwan than its previous positioning on Ishigaki Island, another island in Okinawa Prefecture.¹²

Keen Sword is a biennial US-Japan exercise and one of the two countries’ largest joint military drills, according to The Japan Times. This year’s exercise is scheduled across Japan’s southern island chain. The newspaper said the training is intended to prepare forces more realistically for a possible crisis, including an attempt by China to take Taiwan.¹

Japan may send more military equipment

The Japanese military may deploy anti-ship and surface-to-air missile systems, along with electronic warfare vehicles, to Yonaguni during the exercise, The Japan Times reported. The newspaper characterised the proposed NMESIS deployment as a step beyond previous training on the island, where US forces had brought supplies and practised establishing a forward-operating base.¹

NMESIS has previously appeared elsewhere in the region. The South China Morning Post reported that the system was stationed on Ishigaki during the Resolute Dragon drills in September last year and was also operated elsewhere in Okinawa. The Japan Times said the United States sent the system to the Philippines for exercises last year, prompting criticism from Chinese state media.¹²

Political tensions surrounding Yonaguni

Japan also plans to station surface-to-air missiles permanently on Yonaguni from 2030, according to The Japan Times. A Chinese foreign ministry spokeswoman said that plan would “create regional tension and provoke military confrontation”. The South China Morning Post reported that tensions between Beijing and Tokyo remained present as the new exercise approached.¹²

The Japan Times reported that Japanese Prime Minister Sanae Takaichi emphasised “the strength of the alliance between the two countries” after a New York summit with US President Donald Trump. The newspaper also said Takaichi had previously suggested that Japan could mobilise its military as part of a collective effort to defend Taiwan against an invasion.¹