PLA Faces Pressure to Adapt as US and Japan Track Taiwan Strait Drills

December Drills Put Surveillance in Focus

China's People's Liberation Army began its two days of Justice Mission 2025 exercises around Taiwan on December 29 without prior warning. Yet US and Japanese surveillance aircraft responded immediately, according to a report by the Beijing based defense think tank Lande. Aircraft diverted from regular patrol routes or flew dedicated missions near the exercise areas, showing how closely China's military movements were being watched.

Lande identified a US MQ-4C Triton drone and a Japanese Falcon 2000MSA surveillance aircraft through publicly accessible flight tracking data. Their rapid repositioning made the exercise a case study in the challenge facing Chinese planners: how to prepare and conduct an operation across the Taiwan Strait when other militaries already maintain a persistent presence nearby.

The PLA launched the drills to test operational readiness, meaning its ability to put personnel, equipment and command systems into action. The surveillance response placed another issue at the center of the exercise. Chinese forces must plan for opponents to observe their movements as they happen, including during an attempt to launch a surprise attack.

By January 21, 2026, the debate extended beyond the aircraft seen during those two days. Japan was developing weapons with greater reach and closer operational coordination with the United States. The Philippines was strengthening cooperation with both countries on the southern side of Taiwan. Chinese exercises, meanwhile, were becoming larger and more closely coordinated across military services and geographic commands.

The central contest is about information as much as firepower. Aircraft, ships, radar and other sensors help commanders build a picture of where forces are moving and what they may be preparing to do. The PLA's task is increasingly to operate within that picture while trying to keep its intentions uncertain.

What the Aircraft Movements Revealed

The Lande report described two kinds of response to Justice Mission 2025. Some US and Japanese aircraft changed course from routine patrols to circle nearby areas. Others launched sorties specifically directed toward the drill zones. A sortie is an individual operational flight, such as a mission to gather information about ships or aircraft.

The MQ-4C Triton and Falcon 2000MSA were the aircraft identified in the flight tracking analysis. Their movements illustrated how an existing surveillance presence can quickly concentrate on an unfolding event. The two militaries already had assets operating in the region, allowing them to respond without first building a monitoring presence from scratch.

Chinese planners therefore face a practical problem with surprise. An exercise can begin without public warning, while nearby foreign forces still detect activity and adjust their patrols immediately. Analysts examining the drills argued that the PLA must account for surveillance across several domains when planning operations against Taiwan.

The broader conclusion drawn from the exercise was that secret mobilization in the Taiwan Strait has become increasingly difficult. Moving forces, activating equipment and coordinating an operation all create activity that an opponent can watch. Beijing's challenge includes both carrying out complex maneuvers and managing the information those maneuvers reveal.

A Network Beyond Patrol Aircraft

US and Japanese surveillance extends beyond the aircraft identified during Justice Mission 2025. The regional network includes satellites, sensors beneath the sea, radar stations on land and tools for gathering intelligence through computer networks. Together, these systems can observe different parts of the same military operation.

The US Navy contributes surface warships and submarines equipped with advanced sensors. Japan adds early warning radar and patrols by its Maritime Self-Defense Force. Ships and aircraft are visible targets, but surveillance can also follow electronic signals, missile launches and patterns of communication.

Radio traffic can reveal that units are communicating more frequently. The activation of fire control radar, which helps direct weapons toward a target, can offer another indication of military activity. During the December drills, US and Japanese assets were likely examining such signals to assemble a picture of the Chinese forces involved.

Military planners call that picture an order of battle: an account of the units, equipment and command arrangements an opponent has available. Building it requires combining observations rather than simply counting aircraft or ships. A radar signal, a patrol route and a change in communications may each provide a different part of the picture.

The network creates pressure on the PLA to consider how an operation looks from outside. A force preparing to cross the strait would have to manage its movements while opponents watched physical activity and electronic emissions. The December response illustrated why surveillance has become a central consideration in Chinese operational planning.

Japan Expands Its Security Role

Japan's participation in monitoring the drills reflects a broader change in its security posture. For decades, its Self-Defense Forces operated under a strictly defensive interpretation of the constitution. Tokyo now treats peace and stability across the Taiwan Strait as indispensable to Japan's own security and prosperity.

A report by the Center for Strategic and International Studies described Japan's National Security Strategy, approved in December 2022, as clarifying an intention to make a full contribution to Taiwan's defense. That assessment places Japan closer to the center of planning for a Taiwan crisis, with responsibilities extending beyond observing events nearby.

Japan's defense buildup program focuses on seven critical capability areas. Those identified in the discussion include standoff strike capabilities, integrated air and missile defense, and unmanned assets. Standoff weapons allow forces to attack from a distance. Integrated air and missile defense brings detection and defensive weapons into a coordinated system.

The weapons program includes missiles with greater range for attacking ships and targets on land. Tokyo describes them as counterstrike capabilities, intended to respond to threats. Their reach also changes the military calculations of other countries because Japan would be able to strike targets deeper inside an opponent's territory.

China's and North Korea's large missile arsenals provide the security context for those acquisitions. Japan is also connecting its developing capabilities to the US alliance framework. Surveillance, defensive systems and weapons with greater reach are becoming parts of a more closely coordinated military posture.

Bases and Joint Planning Connect the Allies

The United States and Japan are reportedly preparing a new operation plan for contingencies in the Taiwan Strait, building on existing planning for the Korean Peninsula. Such a plan would address how the allies organize and support a response during a crisis.

Japanese bases would be important to US operations in a conflict. Misawa, Yokota and Kadena air bases, together with the naval facilities at Yokosuka and Sasebo, were identified as locations from which forces could operate. Their value comes from supporting aircraft, ships and the supplies needed to keep missions running.

Japan has invested heavily in ballistic missile defense to protect these facilities and help keep them operational under attack. A ballistic missile travels along an arcing flight path toward its target. Defending bases against those weapons is part of preserving the ability to launch and sustain operations during a conflict.

The alliance's integration also supports the surveillance network. Information can move between Japanese and US commanders, connecting observations to operational decisions. Bases, sensors and shared planning therefore serve related purposes: discovering what is happening, deciding how to respond and keeping the forces needed for that response available.

The PLA Rehearses Larger Joint Operations

The PLA is adapting through exercises that bring its services together on a larger scale. Earlier drills tended to concentrate on the capabilities of individual services. Since 2022, China has normalized joint combat readiness patrols and major exercises directed at Taiwan.

These operations increasingly use scenarios at the scale of an entire military campaign, including rehearsals for joint operations against large islands. A campaign combines multiple military actions toward a broader objective. That requires more coordination than a tactical drill focused on a single unit or task.

The PLA has also begun categorizing exercises by echelon, or level of military organization, while placing greater weight on realism and standardized large annual drills. Those changes are intended to test how units and commanders work together under conditions closer to an actual operation.

The Eastern Theater Command generally leads exercises around Taiwan, but the operational scope now reaches across the Yellow Sea, East China Sea, Taiwan Strait and South China Sea. This wider geography reflects an evolving approach involving multiple theater commands rather than activity confined to one command's area.

The Central Military Commission Joint Operations Command Center centrally manages command and control over these dispersed forces. Exercises across several seas test whether the PLA's command arrangements following its reforms can coordinate units across theater boundaries. The challenge is to keep distant forces working toward the same objective.

China Coast Guard participation adds another element. Coast guard vessels can conduct harassment operations alongside military activity, blurring the boundary between law enforcement and armed operations. For opponents trying to understand Beijing's intentions, that mixture creates a more complicated picture than a deployment consisting entirely of naval warships.

China frames these activities as targeting Taiwan independence forces, seeking to reduce the risk of intervention by other countries. Neighboring states nevertheless view the expanding operations with anxiety amid rising tensions. The PLA's growing ability to coordinate services and commands suggests an effort to burden opposing surveillance systems with the volume and complexity of activity, alongside efforts to preserve secrecy.

North Korea Complicates Japan's Planning

Japan must prepare for security threats involving both the Taiwan Strait and the Korean Peninsula. North Korea's nuclear weapons and ballistic missiles require attention even as Tokyo increases its focus on Taiwan. Estimates cited in the discussion put North Korea's arsenal at approximately 20 nuclear weapons, with enough fissile material for dozens more.

Fissile material is the nuclear material used to produce the explosive reaction in a nuclear weapon. North Korea has also improved its missiles, including the deployment of missiles using solid fuel. Those weapons can be launched more quickly, improving their ability to survive attempts to destroy them before firing.

A potential conflict scenario involves North Korea creating a diversion while China acts against Taiwan. Beijing could encourage tension on the Korean Peninsula to draw US and Japanese forces away from the strait. Japan would then have to divide attention and equipment between threats in different directions.

North Korean submarines carrying ballistic missiles feature in that scenario. Despite being noisy, they could threaten Japan's southern islands or the US mainland, forcing commanders to allocate forces to finding and tracking them. Those demands would compete with other missions requiring aircraft and ships equipped for warfare against submarines.

North Korea's development of cruise missiles with greater range creates another demand on Japan's defenses. Keeping air defense systems oriented toward threats from the west could weaken coverage in the southwest. The strategic concern is that competing threats would stretch the forces available to respond around Taiwan.

The discussion of Beijing's planning also connects this effort to disperse opposing resources with China's partnership with Moscow. The central issue for Japan is the number of commitments it might face at once: protecting its territory, supporting US operations and responding to developments on the Korean Peninsula.

Chinese Assessments Anticipate Japanese Involvement

Chinese academic and military circles are closely examining Japan's changing role. Many Chinese analysts expect Japanese military intervention in a Taiwan conflict, despite doubts in some Western discussions about Tokyo's willingness to fight. Their assessments treat Japan as an important part of the US operational system.

Japan could provide surveillance, refueling and medical evacuation, as well as the bases and logistical support needed by US forces. These functions help keep military operations running. Chinese assessments generally link Japan's participation to the strength of the US commitment, expecting Tokyo to follow Washington's lead.

Beijing has consequently incorporated Japan into its thinking about deterrence, or efforts to discourage an opponent from acting by making the likely costs apparent. Some Chinese analysts have considered strikes on Japanese bases to prevent their use as staging grounds. Others have examined pressure through sea lanes vital to Japanese trade.

Those assessments connect military and economic vulnerabilities. A base can support operations near Taiwan, while shipping routes support Japan's economy. Chinese planning discussions therefore consider ways to influence Tokyo's decisions through threats to both military facilities and access to maritime trade.

The Philippines Adds a Southern Dimension

The Philippines sits on the southern flank of the Taiwan Strait. The Bashi Channel, between Luzon and Taiwan, is a critical maritime choke point, a passage through which ships may need to travel. Control of that channel would be important for a naval blockade or efforts to bring reinforcements into the area.

The United States, Japan and the Philippines have been developing a trilateral security partnership through joint exercises and simulations conducted around a table. In 2024, the three partners held their first humanitarian assistance and disaster response exercise during the annual Balikatan drills. They also established a Multinational Coordination Center to organize operations.

Disaster response requires partners to move personnel and supplies, communicate and agree on responsibilities. The logistical arrangements and command relationships developed through those exercises are also applicable to military contingencies. They give the three countries experience coordinating a response under pressure.

Manila has publicly stated that it is ready to evacuate Philippine citizens from Taiwan in the event of war. It has established a Coast Guard station on Itbayat Island and increased exercises with partners. Noncombatant Evacuation Operations, known as NEO, are plans for moving civilians safely out of a conflict area.

The Enhanced Defense Cooperation Agreement between the United States and the Philippines gives American forces access to bases in northern Luzon. That access increases the ability to operate toward the Taiwan Strait. Wider cooperation also expands radar and patrol coverage, adding to the surveillance and response network surrounding Taiwan.

Monitoring Brings Friction as Well as Awareness

US officials have publicly acknowledged their close monitoring of Chinese activity. In remarks at Yokota Air Base in Japan, Lloyd Austin, speaking as defense secretary, said the Pentagon was watching security conditions in and around Taiwan. He described the People's Republic of China as the US military's pacing challenge over the previous four years, meaning the principal competitor shaping its preparations.

Austin also pointed to Chinese coercive actions in the region and continued monitoring intended to maintain the status quo in the Taiwan Strait. Surveillance flights, however, can themselves become points of confrontation between the two militaries.

In April 2024, China criticized a US Navy P-8A Poseidon surveillance flight through the Taiwan Strait. The PLA Eastern Theater Command called the transit provocative. The US 7th Fleet said the flight followed international law and demonstrated a commitment to a free and open Indo-Pacific.

The United States maintains that it can fly, sail and operate wherever international law permits. China views these transits as provocations threatening peace and stability. The disagreement puts aircraft conducting routine monitoring into the same contested environment they are watching.

The main developments span several years:

• Since 2022, the PLA has normalized joint combat readiness patrols and major exercises targeting Taiwan.
• December 2022: Japan approved its National Security Strategy.
• April 2024: A US P-8A transit through the Taiwan Strait drew criticism from China.
• 2024: The United States, Japan and the Philippines held their first trilateral disaster response exercise during Balikatan.
• December 29, 2025: Justice Mission 2025 began, with US and Japanese surveillance aircraft responding immediately.

Taiwan gains a measure of security from the visible presence of surveillance assets and the growing involvement of Japan and the Philippines. The PLA, meanwhile, is learning to conduct larger operations while opposing sensors track its activity. Observation and efforts to conceal intentions are likely to shape the opening stages of any future conflict.

The Bottom Line

• Lande identified an MQ-4C Triton and Falcon 2000MSA responding to the two days of Justice Mission 2025 drills.
• US and Japanese monitoring combines aircraft with ships, submarines, satellites, radar and other intelligence tools.
• Japan is developing weapons with greater range, protecting bases and strengthening operational planning with the United States.
• PLA exercises increasingly combine services, theater commands and China Coast Guard activity across several seas.
• North Korean threats create competing demands on Japanese and US forces during a potential Taiwan crisis.
• Cooperation with the Philippines adds patrol coverage, access to northern Luzon bases and preparations to evacuate civilians.