US and Japan Turn Taiwan Crisis Plans Into Island Drills and Missile Deployments

Yonaguni puts Taiwan preparations close to the strait

Japan's plan to station a medium range air defense missile unit on Yonaguni, about 110 kilometers from Taiwan, is one of the clearest signs of how quickly Tokyo and Washington are preparing their alliance for a possible Taiwan crisis. Across Japan's southwest, new weapons, larger exercises and changes in military command are turning years of planning into operations on the islands that would matter first.

Yonaguni already hosts a radar site and an electronic warfare unit designed to monitor and disrupt adversary communications. Adding surface to air missiles would strengthen protection against aircraft and other airborne threats near the Taiwan Strait. Nearby islands are receiving Japanese missiles designed to attack ships, while US forces have increased supplies, equipment and training across the region.

The island lies at the end of the Ryukyu chain, an arc of more than 150 islands extending from Kyushu toward Taiwan and the Philippines. Its location places it near sea routes that Chinese forces would likely use in an attempt to coerce or invade Taiwan. For residents, that geography also puts their communities close to any fighting.

US deployments bring several different capabilities. The Army's Typhon missile battery has been stationed on Japanese soil for the first time, while Marine units have practiced with mobile systems for attacking ships and defending against airborne threats. Several MQ 4C Triton drones are also planned for Okinawa to expand maritime surveillance over long periods.

Prime Minister Sanae Takaichi has connected a possible Chinese use of force against Taiwan with Japan's own survival. Her remarks, Beijing's objections and the military activity together show how closely Tokyo now connects a Taiwan emergency with the defense of Japanese territory.

What the command exercise rehearsed

The Keen Edge command post exercise in February 2024 tested a sequence far more demanding than an isolated clash around Taiwan. US and Japanese staffs simulated a Chinese attack on Taiwan, subsequent missile strikes on US bases in Japan and a People's Liberation Army landing on Yonaguni.

A command post exercise tests headquarters, communications and decisions through a simulated conflict. In Keen Edge, the Japanese government classified the scenario as a survival threatening situation. That decision opened the way for the Self Defense Forces to fight under Japan's rules for collective self defense, which allow limited action alongside an ally when Japan's existence is threatened.

US commanders asked Tokyo during one segment to attack a Chinese amphibious fleet in the Taiwan Strait. Japanese officers debated whether to strike escorts and aircraft carriers or the transport ships carrying troops and equipment. They selected the transports, aiming to prevent an invasion force from reaching shore.

The choice explains an important part of the operational thinking. Attacking escorts and carriers could weaken the fleet's air defense, while destroying transports could stop soldiers and heavy equipment from reaching Taiwan's beaches. The exercise placed that decision alongside threats to Japanese islands and US bases.

Keen Edge also exposed practical problems. Commanders had to work out how to share runways among aircraft delivering supplies, fighters conducting missions and teams making emergency repairs under the threat of missile attacks. A workable response depended on keeping transport and combat operations moving at the same time.

Field drills bring the plans onto island terrain

Keen Sword 2025 involved roughly 45,000 personnel and brought US rocket artillery units to Ishigaki, an island closer to Taiwan than to the Japanese mainland. The Iron Fist exercise series has shifted to Japan and now centers on amphibious operations and island defense. US Marines and Japan's Amphibious Rapid Deployment Brigade practice landings and the coordinated use of weapons.

Resolute Dragon 2025 brought the Typhon battery to Marine Corps Air Station Iwakuni. On Ishigaki, Marine units demonstrated the Navy Marine Expeditionary Ship Interdiction System, known as NMESIS, and the Marine Air Defense Integrated System, or MADIS. These exercises test how quickly units can arrive, conceal their positions, fire and relocate in an environment where missiles threaten military sites.

Lt. Gen. Roger Turner, the senior US Marine commander on Okinawa, described the intended deterrent message during a news conference on the island:

These combined exercises should clearly signal to any potential adversary that any aggression will be met with a swift and decisive response.

Turner's message rests on an operational requirement: forces must be able to deploy quickly, stay hidden and strike accurately. Practicing on actual islands gives commanders experience with the geography, weather and infrastructure they would encounter during a crisis.

The milestones behind the current preparations

Japan's present posture combines a legal change made more than a decade ago with more recent exercises and deployments. The sequence shows how permission to act alongside an ally has been followed by practice in making decisions and moving forces.

• 2014: Japan reinterpreted its constitution to permit the limited use of collective self defense when an armed attack on a friendly state threatens Japan's existence.
• 2022: During large Chinese exercises responding to a high profile visit to Taipei, several ballistic missiles landed in the sea just south of Yonaguni.
• February 2024: Keen Edge simulated an attack on Taiwan, missile strikes on US bases in Japan and a Chinese landing on Yonaguni.
• Keen Sword 2025: Roughly 45,000 personnel took part, with US rocket artillery units staging on Ishigaki.
• Resolute Dragon 2025: Typhon deployed to Iwakuni, while NMESIS and MADIS trained on Ishigaki.
• December 1, 2025: Japan's planned Yonaguni air defense deployment and the planned arrival of Triton drones formed part of the alliance's continuing preparations.

The missiles that landed near Yonaguni in 2022 demonstrated the island chain's proximity to military activity around Taiwan. The later exercises tested responses across that same geography, including decisions about protecting bases, striking ships and supporting dispersed units.

Why the island passages matter

The Ryukyu chain forms a natural barrier between the East China Sea and the Pacific, with narrow passages separating its islands. Ships and aircraft often move through the Miyako Strait and passages near Yonaguni. In a Taiwan conflict, Chinese forces would need those routes to maneuver and threaten US and Japanese assets.

Japanese islands provide locations for sensors and missiles to watch those approaches and, during fighting, target ships and aircraft moving through them. The geography gives the alliance a series of observation and firing positions along routes Chinese naval forces would use to reach the Pacific.

Japan's Type 03 Chu SAM is the air defense system planned for Yonaguni. It is designed to engage airborne threats at distances of tens of kilometers. Type 12 missiles, designed to attack ships, are deployed on Ishigaki and other islands and are being upgraded for ranges on the order of 1,000 kilometers.

Yonaguni's electronic warfare teams provide a different form of defense by jamming enemy radars and guidance systems. Combined with radar surveillance and missiles, they give the island several ways to detect or interfere with hostile activity.

Work is also accelerating on an airfield on Mageshima. Part of its purpose is to support US Navy carrier landing practice and provide more capacity for Japan Air Self Defense Force training. More runways, usable ports, supplies stored in advance and mobile missile batteries would give commanders additional options when existing facilities come under attack.

Different missiles, different jobs

NMESIS gives Marine units a mobile launcher for attacking ships. It fires Naval Strike Missiles with a reach of roughly 100 miles and can be operated remotely, making it harder to target. Its role is to threaten naval vessels from positions ashore.

MADIS provides defense against airborne threats at shorter distances. Typhon adds longer reach through its ability to launch cruise missiles and surface to air missiles. From Japan's southwest, that capability can put distant targets within reach.

The common operating method is mobility and control of the signals that reveal a unit's location. Small teams move among different positions, conceal themselves among civilian infrastructure where permitted and prepare to fire from multiple sites. After firing, they need to move again before an adversary can target them.

US Marine Littoral Regiment planning extends that approach across the first island chain, the island arc running through Japan's southwest and the Philippines. The regiment would disperse with mobile rocket artillery, while the US Army's Multi Domain Task Force would deploy weapons capable of striking over long distances in the Philippines.

US guidance calls for temporary expeditionary bases on inhabited islands in Japan's Nansei chain and in the Philippines if a Taiwan contingency becomes imminent. Japan's Self Defense Forces would support US units with fuel, ammunition and transport. Manila has already expanded US access to nine sites and conducted exercises involving systems now present in Japan.

The purpose is to spread precision missiles and sensors along the island chain so forces can monitor Chinese naval movements and, if necessary, block passage into the Pacific. Dispersal creates more operating locations, but units still need reliable supplies and protection once detected.

Tokyo's legal threshold and new commands

Japan's 2014 constitutional reinterpretation permits limited collective self defense. In practical terms, the Self Defense Forces may fight alongside an ally when an armed attack on a friendly state threatens Japan's existence. Exercises now rehearse the steps needed to declare a survival threatening situation and authorize force.

Prime Minister Sanae Takaichi placed Taiwan within that calculation in remarks to lawmakers early this month. She said a Chinese use of force could meet the legal threshold for Japan to act:

Any use of force by mainland China against Taiwan could be a survival threatening situation for Japan.

Takaichi's wording makes the political decision central to any response. Tokyo would need to assess the circumstances and authorize action under its rules. Beijing protested her remarks, and the resulting diplomatic dispute underscored the connection between Taiwan's security and Japan's own defenses.

Japan has also established a permanent Joint Operations Command to coordinate the ground, maritime, air, space and cyber arms of the Self Defense Forces. It is intended to work more closely with US commanders in Japan. Washington is moving to upgrade US Forces Japan into a joint headquarters that can pair with the new Japanese command.

The two countries are cooperating on production of advanced munitions and spreading ammunition and fuel storage across the archipelago. Political leaders in Tokyo remain cautious about explicitly naming Taiwan in alliance plans, even as daily military preparations focus on making a combined response function under pressure.

Moving supplies and protecting civilians

Japan has established a Maritime Transport Group to coordinate movement by sea and accelerated construction and strengthening of airfields and ports in the southwest. US units have recently practiced carrying supplies from Okinawa to Yonaguni, simulating the creation of a forward operating site under pressure.

Those efforts address the problems exposed in staff exercises. Forces need speed, spare routes and the ability to keep operating after damage. Spreading ammunition depots across multiple prefectures reduces dependence on a single storage location, while additional transport capacity helps connect scattered islands.

The central government and local authorities have drafted plans to evacuate about 120,000 residents from remote islands in Okinawa Prefecture within about six days if a Taiwan emergency escalates. Moving that number in that period would require an average of roughly 20,000 people a day.

Drills and surveys on Yonaguni, Ishigaki and Miyako have examined evacuation routes, temporary shelters and medical support. Tokyo has also relocated tilt rotor aircraft to better support island contingencies. Military preparations are being paired with local consultations because the islands are populated communities as well as strategic positions.

The Japan Coast Guard would manage maritime safety and escort evacuations under the planning described. Evacuating people while attacks are underway would be difficult, making transport availability and early decisions central to civilian protection.

Several MQ 4C Triton drones are slated to operate from Kadena on Okinawa, providing persistent maritime surveillance around Taiwan and the East China Sea. No deployment date was given for the drones or the planned Yonaguni missile unit. Japanese fighters already scramble frequently to intercept unidentified drones and surveillance aircraft in southern airspace, with incidents rising over the past few years. Those flights provide early warning and help track patterns of Chinese ships and aircraft passing through nearby straits.

Beijing objects as Taipei welcomes stronger defenses

China views Taiwan as part of its territory and warns against foreign involvement. Chinese warships and aircraft regularly operate around Japan's southwest islands and through the Miyako Strait. Chinese coast guard vessels also continue incursions near the disputed Senkaku Islands, backed by a Chinese coast guard law authorizing force in waters Beijing claims.

Beijing has responded to Japanese statements and deployments with sharp diplomacy and, at times, economic signals. A Chinese Foreign Ministry spokeswoman condemned the proposed missile deployment on Yonaguni:

Deploying missiles on Yonaguni would be extremely dangerous and a deliberate move that breeds regional tensions.

Taiwan officials have welcomed closer coordination between Tokyo and Washington as a stabilizing factor. Their argument is that stronger defenses near Taiwan increase the cost of aggression and give allies more time to respond. Taiwan officials expressed that position in these terms:

Strengthening military facilities on Yonaguni helps maintain security in the Taiwan Strait and benefits Taiwan's national interests.

Direct military ties between Japan and Taiwan remain limited. Contact among coast guard agencies has deepened, however, and quiet information sharing has become more routine. Farther south, expanded US access in the Philippines extends the same island defense concept beyond Japan.

How a crisis could test the alliance

Alliance planning points to a rapidly developing emergency. If warning signs indicate preparations for an invasion, small US Marine teams would disperse across islands in Japan's Nansei chain and the Philippines, taking mobile rocket artillery and missiles for attacking ships. They would watch ocean approaches and threaten Chinese naval groups moving beyond the Taiwan Strait.

US Army forces would position weapons with longer reach to strike from several directions. Japanese units would provide logistics, air defense and coverage against ships from their island batteries. These roles depend on commanders sharing information and political leaders making decisions quickly.

Chinese forces committed to using force would try to neutralize US bases on Okinawa and elsewhere in Japan with missile strikes while moving amphibious groups toward Taiwan. That is the situation behind the exercises' focus on runway use, dispersed supplies and decisions about attacking transport ships.

Mobile units are harder to locate, but become vulnerable when detected. Civilian evacuation would face pressure from the same threats affecting military transport. Alliance coordination would be tested in the first hours, when forces must protect bases, sustain operations and respond to changing information at once.

Tokyo has tried to prepare the public for those demands while retaining caution in its language about Taiwan. The central change is visible on the islands themselves: the alliance is putting personnel, weapons and supplies in the places its crisis plans depend upon, then practicing how to use and support them.

At a Glance

• Japan plans a medium range air defense unit on Yonaguni, about 110 kilometers from Taiwan.
• Keen Edge in February 2024 simulated an attack on Taiwan, strikes on US bases in Japan and a Chinese landing on Yonaguni.
• Japanese officers in that exercise chose to prioritize Chinese transport ships carrying troops and equipment.
• Keen Sword 2025 involved roughly 45,000 personnel; Resolute Dragon 2025 brought Typhon, NMESIS and MADIS into exercises in Japan.
• Alliance plans envision temporary bases across Japan's Nansei chain and the Philippines, with Japanese logistics support.
• Japan has created a permanent Joint Operations Command, while Washington is upgrading US Forces Japan's headquarters.
• Evacuation plans aim to move about 120,000 residents from remote Okinawa islands within about six days.
• China condemned the Yonaguni missile plan, while Taiwan welcomed stronger defenses near the strait.