Overview

On 10 December 2025, the United States publicly backed Japan in a dispute with China after Chinese fighter jets locked fire control radar on Japanese Air Self Defence Force aircraft near Okinawa. Washington criticised Beijing’s actions as dangerous and destabilising, saying they raised the risk of miscalculation in already tense skies close to Taiwan and the Senkaku Islands.

The incident has become a fresh test of the US Japan alliance and of Washington’s wider strategy to deter Chinese coercion along the First Island Chain. By siding clearly with Tokyo and calling out unsafe military behaviour, US officials are signalling that they see Japan’s defence of its airspace as part of a broader effort to protect Taiwan, safeguard sea lanes and uphold a rules based order in the western Pacific.

What US and Japanese Officials Said and Their Positions

According to US and Japanese readouts, a Chinese J 15 launched from the carrier Liaoning repeatedly locked its radar onto Japanese F 15s that were monitoring activity near Okinawa. Tokyo lodged a strong protest, with Defence Minister Shinjiro Koizumi labelling the radar lock a dangerous act that could be interpreted as preparation to fire. Prime Minister Sanae Takaichi told lawmakers that Japan would respond calmly but firmly, stressing that the safety of Japanese pilots and nearby civilians was non negotiable.

A spokesperson for the US State Department said China’s actions were not conducive to regional peace and stability and reaffirmed that the US Japan alliance was stronger and more united than ever. The United States emphasised that it stood shoulder to shoulder with Japan in opposing coercive and unsafe behaviour by Chinese forces. Chinese officials rejected those statements, insisting that their drills were lawful and that Japanese aircraft had approached too closely, and they urged other countries not to be misled by Tokyo.

How US Strategy Uses Japan to Counter China

For Washington, the radar incident is not just a one off crisis but part of a pattern of Chinese military pressure on US allies and partners. The latest National Security Strategy and Indo Pacific defence guidance describe China as America’s most consequential strategic competitor and highlight Japan as a frontline ally whose geography, advanced economy and upgraded defence policies make it essential to any strategy for deterring aggression around Taiwan.

US planners see Japan as a hub for allied operations along the First Island Chain. By backing Japan diplomatically when incidents like the radar lock occur, Washington reinforces Tokyo’s willingness to take on more responsibility, from missile defence to anti submarine warfare and intelligence sharing. In practical terms, this means closer integration of US and Japanese command structures, more joint training and shared planning for contingencies that might begin with harassment and radar incidents but could escalate into larger clashes if not managed carefully.

Protecting First Island Chain Security

The First Island Chain runs from Japan through Taiwan and the Philippines down toward the South China Sea. US and allied strategists argue that if this line is defended successfully, it becomes much harder for China to project power into the central Pacific or to threaten US territories and shipping lanes. The radar incident near Okinawa took place in the heart of this arc, underscoring how quickly local encounters can have broader strategic implications.

Japan’s investments in radars, surface to air missiles and anti ship missiles on its southwest islands are intended to create overlapping coverage with US forces. The goal is to build a network in which any Chinese aircraft or warship operating near Taiwan or the Senkaku Islands is tracked continuously and, if necessary, can be held at risk by allied firepower. By standing firmly behind Japan’s right to monitor and defend this airspace, the United States is signalling that it will not accept a gradual erosion of allied control over the First Island Chain.

How the United States Helps Defend the First Island Chain

US support for Japan goes far beyond statements. The United States maintains significant air and naval forces in Japan, including fighter wings in Okinawa, Aegis equipped destroyers, submarines and intelligence, surveillance and reconnaissance platforms. Recent posture reviews have called for more dispersed and resilient deployments, with smaller, harder to target units spread across multiple bases along the chain.

In a crisis linked to radar incidents or more serious confrontations, US and Japanese forces would aim to share targeting data in real time, coordinate air patrols and, if needed, use air and missile defence systems to protect their bases and population centres. Regular exercises now practice responses to unsafe intercepts, radar lock ons and grey zone tactics, so that pilots and commanders are ready to react in a disciplined way that preserves deterrence but avoids unnecessary escalation.

Boosting the US Defence Industrial Base and Related Economic Sectors

Episodes like the radar dispute also highlight why Washington is pushing to expand its defence industrial base. To sustain a credible presence along the First Island Chain, the United States needs large stocks of air to air missiles, anti ship weapons, air defence interceptors and electronic warfare systems. The National Security Strategy and Pentagon planning documents call for multi year procurement, more co production with allies and faster delivery timelines.

These investments have direct economic effects. Orders for missiles, radars and command systems support jobs at US and allied defence contractors, shipyards and electronics firms. Co development projects with Japan, such as next generation interceptor missiles and advanced sensors, feed into both militaries’ requirements while strengthening high tech manufacturing clusters in the United States and Japan. Spillover from defence innovation into civil aerospace, telecommunications and cyber security can further reinforce growth in sectors that are central to the US economy.

Risks, Diplomacy and the Road Ahead

Security experts caution that growing military activity around Okinawa and Taiwan raises the chance that a miscalculation could trigger a wider crisis. Fire control radar locks are especially sensitive because they signal a possible intent to shoot, meaning that a pilot who misreads the situation might react aggressively. The United States and Japan argue that the best way to prevent such scenarios is to combine firm deterrence with clear communication channels and agreed rules of behaviour at sea and in the air.

While Washington and Tokyo are strengthening their alliance and hardening the First Island Chain, both governments also say they remain open to dialogue with Beijing. The challenge for US strategy is to protect allies like Japan, uphold commitments around Taiwan and maintain economic and technological advantages, all while managing competition with China in a way that avoids war. The radar incident shows how quickly local events can test that balance and why the US Japan alliance remains central to the security of the Indo Pacific.

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