Japan and Russia faced a fresh diplomatic confrontation on Tuesday after Moscow summoned Japan’s ambassador over Tokyo’s protest against Russian President Vladimir Putin’s visit to disputed islands claimed by both countries, adding another strain to relations already badly damaged by the war in Ukraine.
Japanese Ambassador to Russia Akira Muto was expected to respond to the Russian Foreign Ministry’s summons after initially declining to attend, according to Japanese and Russian reports. The dispute followed Putin’s visit last Thursday to the Kuril Islands, territories that Japan calls the Northern Territories and considers an inherent part of its sovereign territory.
The islands have remained one of the most persistent sources of tension between Tokyo and Moscow for decades. The Soviet Union seized the territory at the end of World War II in 1945 and subsequently expelled the Japanese residents. Japan has continued to demand the return of the islands, while Russia maintains that its sovereignty over the territory is not subject to negotiation.
Putin’s visit was particularly significant because it was the first trip by a Russian president to the disputed territories since Dmitry Medvedev visited in 2010. Medvedev served as Russia’s president from 2008 to 2012, during a period when Putin was serving as prime minister.
The latest visit has prompted a sharp response from Tokyo and threatened to further diminish prospects for resolving the long-running territorial dispute.
Japanese Prime Minister Sanae Takaichi said the government’s position remained unchanged, describing the disputed islands as “an inherent part of Japan’s territory, both historically and under international law.”
Tokyo summoned Russia’s ambassador following Putin’s visit, formally expressing its objection to the Russian leader’s presence in the disputed territory.
Moscow responded by summoning Muto, with Russian Foreign Minister Sergei Lavrov accusing Tokyo of crossing what he described as the “line of decency.”
The diplomatic confrontation intensified after Muto did not immediately appear for the summons.
Lavrov said the Japanese ambassador had not attended and suggested that Moscow had received conflicting explanations for his absence.
“We were told either that he was not in Moscow or that he was unwell. We did not quite understand the situation,” Lavrov said.
Russian Foreign Ministry spokeswoman Maria Zakharova later said the ambassador would attend the meeting on Tuesday. Speaking to the state-run TASS news agency, Zakharova suggested that Muto had “suddenly started feeling better” after Lavrov publicly discussed his absence.
The episode added an unusually personal dimension to what had otherwise been a conventional diplomatic dispute.
Japanese public broadcaster NHK reported that Muto’s initial decision not to attend was linked to concerns that Moscow could dominate the discussions and prevent a balanced exchange. According to NHK, Tokyo subsequently held internal consultations before deciding that the ambassador should respond to the Russian summons.
The disagreement over the Kuril Islands is rooted in the final days of World War II.
Soviet forces occupied the islands after Japan’s surrender in August 1945. The Soviet Union subsequently incorporated the territory into its state structure, while Japanese inhabitants were expelled.
Japan refers to the four disputed islands as the Northern Territories. Russia considers them part of the southern Kuril chain and regards its sovereignty over them as a settled consequence of World War II.
The dispute has repeatedly prevented Japan and Russia from formally concluding a peace treaty to end the state of war between them following World War II.
For decades, Japanese and Russian leaders have attempted to negotiate a settlement, with particular attention focused on the four islands of Etorofu, Kunashiri, Shikotan and the Habomai islets.
The issue has periodically appeared to move toward compromise but has never been resolved.
The deterioration of relations since Russia launched its full-scale invasion of Ukraine in 2022 has made progress considerably more difficult.
Japan has aligned itself with the Group of Seven and other Western countries in imposing sanctions on Russia and providing financial and non-lethal defense assistance to Ukraine.
Tokyo’s support for Kyiv has represented a major shift in the broader strategic relationship between Japan and Russia. While Japan has traditionally maintained a cautious approach toward Moscow because of the territorial dispute and its geographic proximity to Russia, the Ukraine war has pushed Tokyo closer to the United States and its European partners.
Japan has also sought to strengthen its defense cooperation with countries across the Indo-Pacific and deepen coordination with NATO members.
The country’s security environment has increasingly been shaped by concerns over Russia, China and North Korea, as well as by the broader competition between the United States and China.
The Kuril Islands dispute therefore extends beyond the question of sovereignty. The island chain occupies a strategically important position in the northwestern Pacific and provides Russia with access between the Sea of Okhotsk and the Pacific Ocean.
Russia has strengthened its military presence on the disputed islands over the years, deploying personnel and military equipment and developing infrastructure.
For Tokyo, the continued Russian military presence represents both a territorial issue and a security concern.
Putin’s decision to visit the islands at a time of heightened tensions with Japan may consequently carry a broader political message.
Analysts have suggested that the Russian president’s visit could have been intended partly as a warning to Tokyo against deepening its military and strategic support for Ukraine.
One potential point of concern for Moscow is Japan’s involvement in the supply chain supporting Ukraine’s air-defense capabilities.
Japan has eased restrictions on defense exports in recent years but continues to maintain significant legal and political limitations on the direct transfer of lethal military equipment to countries engaged in active conflict.
As part of its evolving defense-export policy, Japan has allowed domestically produced Patriot interceptor missiles to be exported to the United States. Those missiles can help replenish American stockpiles that have been reduced as Washington provides air-defense systems and other military assistance to Ukraine.
Although the missiles are not being transferred directly from Japan to Ukraine, the arrangement has indirect implications for Kyiv’s ability to receive U.S. military support.
For Russia, any further relaxation of Japan’s restrictions on defense exports could therefore become an important concern.
Moscow could also view deeper Japanese cooperation with NATO and other Western security structures as part of a broader strategic alignment against Russia.
Japan is not a NATO member, but it has strengthened cooperation with the alliance in recent years as security challenges have increasingly extended beyond Europe.
Tokyo has also expanded defense partnerships with the United States, Britain, Australia, the Philippines and other countries.
The Japanese government argues that these relationships are necessary to respond to a deteriorating regional security environment.
Russia, however, has repeatedly criticized the growing involvement of NATO countries in the Indo-Pacific and has warned against what it sees as the expansion of Western military influence toward Russia’s Far East.
The Kuril Islands dispute consequently sits at the intersection of territorial politics, military strategy and the wider geopolitical confrontation created by the Ukraine war.
For Japan, the territorial claim remains a longstanding national issue. Tokyo has consistently maintained that the four Northern Territories were never legitimately incorporated into the Soviet Union and that Japan’s sovereignty over them is supported by its historical and legal interpretation of the postwar settlement.
For Russia, relinquishing the islands would carry significant strategic and political costs. The territory forms part of Russia’s defensive position in the Far East and contributes to Moscow’s control of access to the Pacific.
The latest diplomatic dispute also comes after years of declining political trust.
Before the Ukraine war, Japan and Russia had attempted to improve relations through high-level meetings and economic cooperation. Former Japanese Prime Minister Shinzo Abe and Putin held numerous meetings and sought progress on the territorial dispute and a long-delayed peace treaty.
Economic cooperation was also presented as a possible mechanism for improving relations.
However, Russia’s invasion of Ukraine fundamentally altered the diplomatic environment. Japan joined Western sanctions and became increasingly critical of Moscow’s military actions, while Russia placed Japan among countries it considers unfriendly.
The territorial dispute, which had once been managed alongside economic and diplomatic engagement, has consequently become part of a much broader confrontation.
Putin’s latest visit is likely to reinforce that trajectory.
For Tokyo, the challenge is to maintain its longstanding claim to the Northern Territories while avoiding further escalation with a neighboring nuclear power. At the same time, Japan is under pressure to strengthen its support for Ukraine and coordinate more closely with the United States and European partners.
For Moscow, the dispute provides an opportunity to reinforce its sovereignty claims and signal that Russia remains willing to challenge Japan’s strategic choices.
The exchange of diplomatic summonses underscores how narrow the space for compromise has become.
The Japanese ambassador’s expected meeting with Russian officials on Tuesday may provide an opportunity for both sides to restate their positions, but there is little indication that either government is prepared to change its fundamental stance.
Instead, Putin’s visit and the subsequent diplomatic confrontation appear likely to deepen the political divide between Moscow and Tokyo.
The Kuril Islands dispute has survived the Cold War, changes of government and numerous rounds of negotiations. The war in Ukraine has now given the dispute a new strategic dimension.
What was once primarily a bilateral territorial disagreement has increasingly become part of the wider contest between Russia and the Western-aligned security architecture in the Indo-Pacific.
As Japan expands its defense partnerships and Russia strengthens its military posture in the Far East, the disputed islands are likely to remain not only a symbol of unfinished business from World War II but also a significant flashpoint in the evolving security competition across the northern Pacific.
