Japan has found itself at the center of a stormy summer of maritime disputes, as tensions with both South Korea and Russia have flared over contested waters and islands. With diplomatic protests flying back and forth, military exercises announced, and sovereignty claims restated, the region’s fragile equilibrium is being put to the test yet again.
The most recent flashpoint occurred on August 16, 2025, off the coast of the Takeshima Islands in Shimane Prefecture. According to the 8th Regional Coast Guard Headquarters, the South Korean research vessel Onnuri was observed at approximately 12:15 p.m. lowering what appeared to be a wire into the sea within Japan’s territorial waters, west of the disputed islands. The incident prompted an immediate and strong reaction from Tokyo.
Later that day, Masaaki Kanai, director general of the Asian and Oceanian Affairs Bureau at Japan’s Foreign Ministry, lodged a stern protest with Kim Jang Hyun, charge d’affaires ad interim at the South Korean Embassy in Japan. The Japanese Embassy in South Korea followed suit, registering its objections directly with the South Korean Foreign Ministry. The rapid diplomatic response underscored just how sensitive the Takeshima issue remains for both countries.
While the South Korean side has not publicly commented on the specifics of the research activity, the episode is just the latest in a long series of disputes over the islands – known as Dokdo in South Korea and Takeshima in Japan. Both nations claim sovereignty, and incidents involving fishing boats, coast guard vessels, and research ships have become almost routine. For Tokyo, any perceived encroachment is met with swift diplomatic pushback, while Seoul maintains that its activities in the area are entirely legitimate.
But Japan’s maritime headaches have not been limited to its southern neighbor. Just days after the Takeshima incident, Tokyo was forced to contend with another, arguably more ominous, challenge—this time from the north. On July 28, 2025, Russia informed Japan that it would be conducting live-fire military exercises in waters north of Shikotan Island, part of the disputed Northern Territories, from August 1 to September 1. The notice included navigation warnings for the duration of the drills, which Moscow insisted were routine training exercises.
Japan’s response was swift and unequivocal. On August 18, 2025, the Foreign Ministry summoned officials from the Russian Embassy in Tokyo to convey its formal protest. The ministry made clear that Russia’s military activities on the islands—known as the Northern Territories in Japan and the Southern Kurils in Russia—are “incompatible with Japan’s position and therefore unacceptable.”
The dispute over these four islands off Hokkaido dates back to the end of World War II, when they were occupied by Soviet forces. Decades later, the two countries have still not signed a formal peace treaty, and the islands remain a persistent source of friction. According to Defense Blog, the Japanese government has repeatedly emphasized that it does not recognize Russia’s presence on the islands or any related military operations, vowing to continue asserting its position through diplomatic channels.
This is not the first time in recent months that Russia has staged military exercises in the area. Similar drills were previously announced in April, and again between June and July 2025. Japanese officials argue that such activities not only complicate diplomatic engagement but also contribute to heightened regional tensions. “Russia’s repeated military maneuvers undermine stability in Northeast Asia, where Japan is also facing increased Chinese activity in the East China Sea and continued missile launches from North Korea,” Japan’s Foreign Ministry stated, according to Defense Blog.
The confluence of disputes with both South Korea and Russia has put Japan’s foreign policy and defense posture under the microscope. It’s not just about sovereignty claims, but about the broader security environment in Northeast Asia—a region where old wounds and new ambitions often collide. The Japanese government’s responses have reflected a growing determination to assert its interests, both diplomatically and militarily.
In a notable development, Japan’s Ground Self-Defense Force has announced plans to conduct its first-ever live-fire drill of the Type 88 surface-to-ship missile system near Hokkaido, close to the disputed Kuril Islands. This move marks a strategic shift in Japan’s defense posture, signaling Tokyo’s intent to bolster its deterrence capabilities in the face of what it sees as mounting threats from neighboring powers.
Yet, even as Japan seeks to project strength, officials are keenly aware of the risks of escalation. The government has reiterated its commitment to resolving disputes through dialogue and diplomatic channels, even as it stands firm on its territorial claims. “Japan does not recognize Russia’s presence on the islands or any related military operations and will continue to assert its position through diplomatic channels,” officials confirmed, according to Defense Blog.
For ordinary Japanese citizens, the stakes may feel abstract—after all, most have never set foot on the disputed islands. But the issues at play are anything but theoretical. Sovereignty over Takeshima/Dokdo and the Northern Territories/Southern Kurils carries not just symbolic weight, but practical implications for fishing rights, resource exploration, and national pride. Each incident, whether involving a research vessel or a military drill, becomes a test of resolve and a reminder of history’s long shadow.
The regional context only adds to the sense of urgency. With China ramping up its maritime activities in the East China Sea and North Korea continuing its missile launches, Japan finds itself navigating an increasingly complex and dangerous neighborhood. The government’s recent actions reflect a recognition that it cannot afford to let any challenge—no matter how small—go unanswered. As one senior official put it, “We must remain vigilant and resolute in defending our territory and interests.”
Of course, each of the major players has its own narrative. South Korea views its activities around Dokdo as an exercise of legitimate sovereignty, while Russia maintains that its military drills are routine and within its rights as the controlling power on the Southern Kurils. For Tokyo, however, these explanations ring hollow, and the diplomatic protests are as much about sending a message to domestic audiences as to foreign governments.
Looking ahead, there are no easy solutions in sight. The disputes over Takeshima/Dokdo and the Northern Territories/Southern Kurils have resisted resolution for generations, and the current flurry of incidents suggests that a breakthrough is as elusive as ever. Still, Japan’s recent actions—both in the diplomatic arena and on the defense front—demonstrate a country determined not to let its claims be eroded by inaction or acquiescence.
As summer draws to a close, the waters around Japan remain as contested as ever, and the world is watching to see how Tokyo will balance assertiveness with restraint in a region where history is never far below the surface.
