Defence Minister Sergei Shoigu announced the new construction on the Kuril Islands on Friday, Russian state news agency TASS reported. The islands, the most southerly of which lie within sight of Hokkaido, were seized by Soviet troops in the closing days of World War II.
“Moscow wants to show Japan that actions in support of Ukraine have costs and that those costs are not in Japan’s best interests,” he said.
Weakening Japan’s resolve on Ukraine would be a coup for Russia, although the islands are critical to its military ambitions in the Asia-Pacific.
“The importance of the islands goes well beyond any military bases that they build there,” said Garren Mulloy, professor of international relations at Daito Bunka University and a specialist in military issues.
“Those bases will be the eyes and ears into northern Japan, keeping Russia up to date on what Japan is doing based in its radar signals and, by extension, what its ally the US is also doing,” he said.
The chain of 56 major islands stretch more than 1,150km (715 miles) from the tip of northern Japan to the Kamchatka Peninsula, Mulloy pointed out, effectively enclosing the Sea of Okhotsk.
“Russia has come to consider the Sea of Okhotsk as its own exclusive area, and it is important as they can almost guarantee that it is free of foreign submarines of any other country and is a bastion for their own ballistic missile submarines,” he said.
“This entire area is protected by the Kurils, and they want to keep it that way.”
The chain of islands may not be as impenetrable as Russia would like, however, as US submarines covertly tapped Soviet undersea military communications cables in the Sea of Okhotsk in the 1970s.
In February 2022, the Russian defence ministry claimed to have detected a US Virginia-class submarine that its forces “expelled” from the area. The US Navy denied that one of its vessels was there.
The new facilities are likely to include improved air monitoring systems, Mulloy said, and Russia is likely to boost its capabilities on the islands, some of which date back to the 1970s and are overdue for replacement.
While the new bases are a concern, they are not a significant new threat to Japan, Brown said.
“There have been reports in the past about weapons being deployed, such as new anti-ship missiles in 2016, but this is a positive for Japan as these are defensive systems. It would be a lot more worrying for Japan if Russia was boosting its offensive capabilities there.”
There have been intermittent talks on the future of the islands, including the possibility of Russia returning some territory, but Moscow has hardened its stance after Japan sided with most of the international community to support Ukraine.
“Putin is afraid of flying and is extremely careful when he travels, so I’m not sure he will actually go through with a visit,” Mulloy said.
“He may send his prime minister or the defence minister in his place unless there is a significant change in the military situation in the region and there is suddenly a very good reason for him to go.”