China has found a new way to test Japan’s patience—this time, in the skies.

In June, a Japanese Navy reconnaissance aircraft reportedly engaged in a dangerous maneuver with a Chinese military jet over the Indo-Pacific. That same month, two Chinese aircraft carriers—the Shandong and the Liaoning—conducted takeoff and landing drills within Japan’s exclusive economic zone (EEZ). By any international standard, Japan holds sovereign rights over its EEZ. These maneuvers by the Chinese vessels amounted not only to an incursion but a deliberate display of military coercion, carried out in plain sight.

The word “harassment” feels apt when describing Beijing’s increasingly provocative behavior in the skies.

But Tokyo has not let these actions go unanswered. Japan has repeatedly accused China of violating its EEZ—allegations that seem to roll off Beijing’s back. In response to the latest encounter, China’s Foreign Ministry insisted that the aircraft carriers operated in “relevant waters” and within the bounds of international law.

When China claims compliance with global norms, it appears to suggest either that Japan misunderstands those norms or that China has crafted its own interpretation of them. Either way, Beijing’s position leaves little space for bilateral discussion, much less acknowledgement that its actions may be eroding regional peace. And without acknowledging harm, there’s no incentive for an apology.

Japan is hardly the only country on the receiving end of China’s aerial brinkmanship. According to the U.S. Department of Defense, the People’s Liberation Army (PLA) has a pattern—lengthy and well-documented—of dangerously intercepting U.S., allied, and partner aircraft over the Indo-Pacific. These are not random encounters, nor the result of incompetence (unless one accepts the unlikely premise that China’s military pilots are grossly undertrained). Rather, the interceptions appear systematic, calculated—more choreographed than chaotic. Think Top Gun meets geopolitical messaging.

From President Xi Jinping’s vow not to rule out the use of force in “reuniting” with Taiwan, to China’s increasing friction with Japan over the East China Sea, the through line is clear: Beijing’s ambitions in the Indo-Pacific are far from subtle. With the People’s Liberation Army Navy (PLAN)—now the world’s largest by number of vessels—China appears intent on bringing the region under its sphere of influence. What’s happening near Japan is just one front in a broader campaign.

True, Japan’s Self-Defense Forces (SDF) have seen their budgets rise to historic post-war levels. But on paper, they still pale in comparison to China’s military might. Beijing likely sees this disparity as an invitation to push boundaries without fear of reprisal.

And to date, there have been few dramatic consequences.

Still, Tokyo’s response has been anything but inert. If not loud, it has been quietly assertive. Following the aircraft carrier drills in early June, Japan significantly increased its air patrols. But that was only the beginning. Later that month, Japan conducted its first domestic missile test on Hokkaido—its northernmost main island. Given Japan’s historical reluctance to hold such tests on its own soil, this marked a striking shift. The message was unambiguous: deterrence is on the table.

Tokyo appears poised to double down. On its easternmost island in the Western Pacific—near where the Chinese carriers had been spotted—Japan reportedly plans to establish a missile-firing range. This isn’t simple retaliation. Nor is it an exercise in mimicry. Japan is carving out its own language of military resolve.

What Japan is doing is neither escalation nor acquiescence. It’s a measured buildup of defense capabilities in response to what it perceives as an increasingly volatile neighbor. Given China’s repeated incursions into Japan’s EEZ, along with recent airspace provocations, Tokyo has every reason to bolster its defenses. In this context, such moves fall well within the bounds of self-defense—without violating Article 9 of its pacifist constitution.

China’s Foreign Ministry may insist its actions are defensive. But that logic holds little water in Tokyo, especially when the provocations are unprovoked and the incursions into Japanese sovereign waters so blatant. When Beijing tells Japan to respond “objectively and rationally,” it misses the irony: Tokyo already has.

What’s not rational—or objective—is harassing another nation’s aircraft in its own backyard.