A historic first visit by a Russian president to a Pacific island chain claimed by both Moscow and Tokyo has reignited a territorial dispute that has simmered since the end of the Second World War. Vladimir Putin's trip to Iturup, the largest of the disputed islands, drew immediate condemnation from Japanese leaders who view the excursion as a direct challenge to their sovereignty claims. Main Developments Putin's journey to the island chain on Thursday marked his first-ever visit to the territory, according to Russian state media. During his time on Iturup, he met with the regional governor and toured a fish-processing plant, a hospital, and a school, presenting a picture of routine administrative oversight over the region. Japan's response was swift and unequivocal. Prime Minister Sanae Takaichi called the visit "absolutely unacceptable," stating that it "offends the sentiments of the Japanese people" and runs counter to Tokyo's longstanding position on the islands, which Japan refers to as the Northern Territories. Read also: Steering Failure: How a Container Ship Grounded in India's Hooghly Foreign Minister Toshimitsu Motegi echoed those sentiments, declaring that the islands "are an inherent part of Japan's territory both historically and under international law." The diplomatic friction escalated further when Motegi summoned the Russian ambassador to deliver a "strong protest" over the visit, as confirmed by Japan's Ministry of Foreign Affairs. Background The four contested islands—Kunashir, Habomai, Shikotan, and Iturup in Russian; Kunashiri, Habomai, Shikotan, and Etorofu in Japanese—anchor the volcanic Kuril archipelago, which arcs from Russia's Kamchatka Peninsula toward Japan's northern island of Hokkaido. Soviet forces seized the islands in 1945, deporting roughly 17,000 Japanese residents in the process. Strategic value has defined the islands' modern history. During the Cold War, they provided air and sea bases as the Soviet Union confronted the United States and its Pacific ally, Japan. Moscow has since continued to bolster its military footprint across the territory, which is home to about 20,000 Russian citizens despite its harsh climate. The islands also hold economic significance beyond their strategic position, with mineral deposits including gold and silver alongside rich fishing grounds. These resources have made the territory more than a symbolic point of contention between the neighbouring nations. Why It Matters Bilateral relations between Tokyo and Moscow have deteriorated sharply since Russia's full-scale invasion of Ukraine in 2022. Japan joined other G7 nations in sanctioning Russia and has provided financial support and non-lethal defence equipment to Kyiv, a stance that has deepened the rift between the two capitals. Putin directly addressed that tension during his visit, pushing back against Japan's characterization of Russia as a security threat. "Japan has identified Russia as a main source of threats," he said. "We are not threatening Japan. On the contrary, it has territorial claims against our country." The timing of the visit amplifies its significance. Putin travelled to the Kurils immediately after a Wednesday stop on the nearby Russian island of Sakhalin, where he held discussions on "ensuring the security of Russia's eastern borders" while the Russian navy conducted drills in the region—a pointed display of military posture near Japanese territory. What's Next The diplomatic fallout from Putin's visit is likely to harden positions on both sides of the dispute. Japan's protest through its foreign ministry signals that Tokyo intends to press its claim through official channels, though previous attempts at negotiation have yielded little progress over the decades since the Soviet occupation. With Russia's military presence on the islands continuing to grow and Japan's security alignment with the West deepening, the territorial question appears no closer to resolution. The visit has set the stage for a further cooling of relations, leaving the future of the Northern Territories as fraught as ever.