SEOUL, South Korea — Japanese, U.S. and other militaries from as far afield as Europe kicked off “Exercise Keen Sword 27” Monday in the waters around some of Japan’s most strategic maritime terrain.
The 18th edition of the joint military biennial drills, which run through Oct. 29, is the largest ever and mainly based around Japan’s Ryukyu Islands in the southwest, but reportedly includes areas off central Japan.
In addition to 45,000 Japanese troops and 11,000 U.S. service members, the exercise’s friendly “Blue Force” includes units and assets from France, Germany, the Netherlands, New Zealand and the Philippines, U.S. Pacific Command said in a press release issued from Okinawa, Japan.
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British and South Korean troops will observe.
“Today, four decades strong, Keen Sword stands as the absolute pinnacle of combat-ready exercises in the Pacific, with the most capable and consequential alliance in the world training alongside our international partners,” U.S. Marine Corps Lt. Gen. George B. Rowell, deputy commander of U.S. Pacific Command, said at the exercise’s opening ceremony.
According to PACOM, training modules include “air and missile defense, facility protection and repair, logistics and resupply, casualty evacuation and maritime operations.”
Gen. Hiroaki Uchikura, chairman of Japan Self-Defense Forces’ Joint Staff, told a press conference last week that “the actual rapid deployment of [Self Defense Forces] and U.S. military assets to the [southwestern] island regions … is of great significance.”
Observers have criticized the historical lack of cooperation between Japan’s air, sea and land forces. A Joint Operations Command was stood up in March 2025.
As is customary, the exercise’s antagonistic “Red Force” is not identified, but China is widely seen as the likeliest challenge in the southwest.
Japanese Prime Minister Sanae Takaichi infuriated Beijing last year when she told the Diet that a Taiwan contingency would trigger the activation of the Japanese military. Communist China claims democratic-run Taiwan as its province.
Despite heavy diplomatic and economic pressure from Beijing, Ms. Takaichi has not retracted her remarks.
The Ryukyu Islands, between Japan and Taiwan, include straits that China’s People’s Liberation Army Navy (PLAN) would have to transit to blockade or surround Taiwan.
On Oct. 14, the PLAN’s Liaoning aircraft carrier strike group transited the Miyako Strait, south of Okinawa, en route to the open waters of the Western Pacific.
The biggest contingent of U.S. Forces Japan is based in Okinawa, the largest of the Ryukyus.
Some Keen Sword 27 drills will take place off Yonaguni, the farthest of the Ryukyus from Japan, just 70 miles east of Taiwan. Monday’s exercise opening ceremony was held on Ishigaki, just some 60 miles west of Yonaguni.
Assets being deployed for the drills include the U.S. NMESIS ship killer missile system and MADIS air-defense system.
NMESIS, the Navy-Marine Expeditionary Ship Interdiction System, is a ground-based, anti-ship missile system used by the U.S. Marine Corps as a key asset in its recently assigned littoral defense mission set. With a range of up to 130 nautical miles, the air-deployable launch platform, mounted on a mobile chassis, enables land-to-sea “shoot and scoot” tactics.
It is being paired with the vehicle-mounted MADIS, or Marine Air Defense Integrated System. MADIS combines Stinger missiles, a 30mm rotary chain gun, a 7.62mm minigun with a radar suite and electronic warfare systems, enabling the shoot-down of enemy aircraft as well as the hard kill or soft kill of incoming drones.
The U.S. Marine Corps, traditionally a seaborne assault force, stood up its first Littoral Combat Regiment in 2022, with its likely operational areas being the Ryukyus and/or the Philippines. Both offer zones from which key maritime straits can be area-denied.
Japan is deploying its new Type 25 long-range, land-to-sea missile system, which has the range to strike targets out to 620 miles. Japanese media state that it is the first time the Type 25s have been moved from their base in Japan’s main islands.
The Liaoning is not the only heavy carrier at play off Japan at present.
It is not yet known if the USS Theodore Roosevelt aircraft carrier strike group will take part in Keen Sword 27.
The USS Abraham Lincoln, which is based in Japan, was heavily engaged in the Middle East and is currently docked in San Diego. The Roosevelt arrived in Japan last week.
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