The fact that Japan is a neighbor of Russia is often overlooked, especially in the West. In fact, Japan has had no land border with Russia for 79 years. But Japan has always faced Russia across the Sea of Japan and the Sea of Okhotsk, and until 35 years ago was at the forefront of the Cold War in Asia. Now, as the geopolitical conflict between Russia and the West reemerges, Japan is once again on the front line.
As during the Cold War, the focus is on the sea. Most of the ground forces in the Russian Far East are believed to have been redeployed to the battlefields of Ukraine, and many garrisons have been emptied. In contrast, the Russian Pacific Fleet’s submarine force is being steadily built up, with particular emphasis on the modernization of nuclear ballistic missile submarines.
After studying Russia for 20 years in close conjunction with the Japanese government, I believe that Western allies would benefit from better understanding Japan’s perspective on the military realities in the Russian Far East. The issue is not simply the growing number of submarines. Satellite imagery shows that Russia’s nuclear ballistic missile submarine fleet has become noticeably more active in recent years. The risk is that growing Russian submarine activity in the north of Japan could strain the deterrent resources of the U.S.-Japanese alliance in the face of the Chinese threat. This calls for a concerted Western response. Together with their Indo-Pacific partners, the United States and Japan have sought to balance Chinese military power. Now, with Russia’s renewed activity, this strategy should be extended northward. Increased Japanese cooperation with Canada would be an excellent first step.
Cold War Clashes
Tsushima is a place steeped in history. About a century ago, one of the greatest naval battles in history was fought in the Tsushima Strait, where the Japanese Navy defeated the Russian Baltic Fleet.
However, the role that the Tsushima Strait played during the Cold War is not well known. Tsushima was the chokepoint for the Soviet fleet sailing from Vladivostok to the Pacific and Indian Oceans. Just as Russian Admiral Zinovy Rozhdestvensky had to pass through Tsushima during the Russo-Japanese War, so too did Soviet submarine captains.
Nuclear-powered ballistic missile submarines were no exception. Submarines from the Soviet Northern Fleet were making various efforts to evade underwater hydrophone systems, as attested to by American and Soviet submariners. The same thing was happening in the waters around Japan. Soviet submarines usually cut off their engines just short of the Japan Maritime Self-Defense Force’s surveillance posts in the Tsushima Strait, and then ride the currents out into the East China Sea in silent navigation. Soviet corvettes were always anchored in the strait, and when the nuclear submarines passed by, they would turn on their engines to jam Japan’s underwater hydrophones.
On the other hand, it was possible to reach the Pacific Ocean from Kamchatka without being hindered by chokepoints. Thus, the submarine units of the Pacific Fleet gradually came to make this peninsula their main base, from where almost every month a Yankee-class submarine (Project 667A) would depart for the patrol area known as the Yankee Box, located 2,000–2,500 kilometers off the West Coast of the United States. On average, each Yankee patrol lasted one and a half months.
In the mid-1970s, the Delta I– (Project 667B) and Delta III-class (Project 667BDR) submarines appeared in the Pacific Fleet. Equipped with long-range R-29 and R-29R ballistic missiles, Deltas no longer needed to sneak across the Pacific to waters off the U.S. mainland. Instead, the strategy was to retreat to waters near the Soviet Union, where it would be easier to obtain support from friendly forces. In addition, Deltas had another merit. While the Yankee needed to travel at a high speed of 15 knots when heading for the coast, Deltas could travel at a lower speed, four to eight knots. This greatly contributed to increasing their survivability.
Western analysts referred to the resulting Soviet strategy as one of submarine “bastions.” The most famous bastion would be the Barents Sea for the Northern Fleet’s nuclear-powered ballistic missile submarines. The Pacific Fleet’s bastion, on the other hand, was the Sea of Okhotsk. Shortly after the first Delta I was deployed in 1974, the Soviet Union started fortifying the area around the Sea of Okhotsk. The first step was the deployment of ground forces: the 18th Machinegun Artillery Division (18 PulAD) was formed and dispatched to the South Kuril Islands for the first time in 20 years. Those islands, as well as the Sakhalin Island, were armed with surface-to-ship missiles and air defense systems. In addition to these developments, a huge caldera in Simushir Island was transformed into a submarine base.
Modern Challenges
Stories like these remain relatively unknown in the West, amidst a great focus on the undersea battles in the North Atlantic. But they are still pertinent today.
After the collapse of the Soviet Union, the Pacific Fleet’s nuclear-powered ballistic missile submarine units found themselves in a difficult situation. Due to a drastic reduction in the defense budget and hyperinflation, the Russian military could not maintain itself, and officers and soldiers did not even have enough food for their daily meals. The nuclear reactors of submarines were used to supply electricity to homes rather than for nuclear deterrence patrols. From the late 1980s into the 1990s, the number of Russian Navy submarine patrols continued to decline, and by the early 2000s it had almost reached zero.
The fact that huge sums of money were being wasted on maintaining submarines that did not even move was not good news for the Russian military. In the 1990s, Andrey Kokoshin, the secretary of the defense committee, was planning to concentrate the nuclear-powered ballistic missile submarines of the Northern Fleet by closing the submarine base in Kamchatka. When President Vladimir Putin came to power in 2000, Chief of the General Staff General Anatoly Kvashnin is said to have advised him to close the Kamchatka submarine base. But Putin rejected this proposal — or so he claimed in a 2012 paper on defense policy. And at the time the paper was published, the Sevmash shipyard was building new ballistic missile subs for deployment on the Kamchatka Peninsula.
If the vessels in question — two Borei-class (Project 955) submarines — had not been deployed in 2015–16, the Kamchatka Peninsula base might have been abandoned after all. Whatever Putin may have said, the Pacific Fleet’s nuclear-powered ballistic missile submarine force was lean and decrepit. By the early 2010s, there were only three aging Delta III submarines left, and their activity was very sluggish. While all the Delta IVs in the Northern Fleet had been modernized, the Delta III–class submarines in the Pacific Fleet had not been given the same opportunity. This may have been because the Sevmash shipyard, where they were built, was very far from Kamchatka, making maintenance difficult. In the end, experts believed that the day was not far off when the nuclear-powered ballistic missile submarines would disappear from the Russian Pacific Fleet, and when that happened, the fleet would have become a coastal fleet of small surface ships and conventionally powered submarines. It would have reverted to the Pacific Fleet of the Stalin era before Admiral Sergei Gorshkov began to pursue his dream of an ocean-going navy.
However, with the introduction of the Borei class, the Pacific Fleet managed to continue to play a strategic role. In addition, three upgraded Borei A (Project 955A) submarines started to arrive to the fleet after 2022, and all of the old Delta III submarines were decommissioned. The Pacific Fleet’s nuclear-powered ballistic missile submarine force has been greatly expanded in both size and quality, becoming almost comparable to that of the Northern Fleet.
Intensifying Russian Submarine Patrols
The problem is not just that the number of submarines is increasing. Their level of activity is also increasing and could strain the deterrence assets of the U.S.-Japanese alliance. Let me begin by describing Russian submarine activity in the waters around Japan.
I was the first individual user of Maxar Technologies in Japan. I still remember the look on the salesman’s face when I said, “Well … I want to buy satellite imagery, as an individual.” Anyway, I got access to optical satellite imagery with a ground resolution of 30 centimeters. I also got access to synthetic aperture radar satellites developed by a Japanese company.
Using these resources, I set about identifying the patrol patterns of the Russian Navy’s nuclear-powered ballistic missile submarines. I continued to observe what types of submarines were docked at the base in Kamchatka.
Observations have continued since June 2021. They reveal that patrols by Russian Pacific Fleet nuclear-powered ballistic missile submarines have become more frequent and longer over the past three years. From 2021, when the observations began, until around 2022, Russian nuclear-powered ballistic missile submarines conducted only one or two voyages of over a month (most likely nuclear deterrence patrols) per year in addition to several relatively short voyages of one to three weeks. Furthermore, in 2023, there was never a confirmed deployment lasting more than a month. Two Borei-As, which were sent to Kamchatka in 2022-23, appear to be treated as “rookies” for some time after their deployment.
From January to September 2024, however, there were already three confirmed patrols of more than a month, and two of them lasted more than two months. More interestingly, all of these long patrols were carried out by the Borei-As. The rookies are finally starting to make their mark. In 2024, the Emperor Alexander III was also deployed as the third Borei-A. It is believed that one or two more will be deployed.
It is also believed that the special mission nuclear submarine Belgorod (Project 09852), equipped with the Poseidon nuclear-powered unmanned underwater system, will be deployed to Kamchatka. It is highly likely that it will be tasked, under the command of the Main Directorate of Deep Sea Research of the Ministry of Defense, with surveying the locations where critical underwater infrastructure, such as submarine cables, are laid and even damaging them. Threats by Main Directorate of Deep Sea Research activities have been noted in Europe since the 2010s, but the lack of large bases on the Pacific side has meant that the sense of crisis on the Japanese side has been low. However, the situation will change in the near future, probably in the short term.
Strategic Implications
This is a worrying development for Japan’s security community. In the 1980s, the Japan Ground Self-Defense Force adopted a strategy called Northern Forward Defense. With the Sea of Okhotsk being the patrol area of the Soviet Union’s ballistic missile fleet, Hokkaido, which juts out far into the sea, must surely have been a prime target for attack. The Northern Forward Defense Strategy was to fortify the island with powerful ground forces, including Japan’s only armored division, and to deploy long-range surface-to-ship missiles. At the same time, the Japan Ground Self-Defense Force strengthened its anti-submarine warfare capabilities. As the number and capabilities of Soviet submarines operating in the waters around Japan increased dramatically, an anti-submarine warfare task force was formed around destroyers equipped with anti-submarine helicopters, and it was also decided to deploy 100 P-3C patrol aircraft. These were the noisy aircraft with prominent “tails” that used to fly around my hometown.
After enjoying the peace dividend for about 15 years, the Japanese security community turned its attention to the southwest of Japan as China’s naval and air forces began to grow rapidly in strength. The Japan Ground Self-Defense Force adopted a “southwest shift” policy, and Hokkaido came to be seen as a strategic reserve base rather than a front line.
This is the background to the increased Russian submarine activity and why it’s so worrying. If the number of deployed Borei-A submarines continues to increase, and assuming that each submarine conducts patrols for an average of two months, it is predicted that there will always be one nuclear-powered ballistic missile submarine deployed in the Sea of Okhotsk. However, the limited resources of the Japan Ground Self-Defense Force and the U.S. Pacific Fleet are already forced to work on a tight rotation. What if the situation in the Taiwan Strait deteriorates? What if a major war breaks out in the Middle East? The person responsible for fitting bells to Russian submarines may be temporarily absent.
What’s more, the situation is complicated by the fact that Russia has allowed China into the area. Fifteen years ago, Russia would never have allowed the Chinese fleet to operate in the Sea of Okhotsk or the Arctic. In fact, when the Chinese fleet transited the Sea of Okhotsk without permission in 2011, Russia expressed its dissatisfaction by conducting missile-firing exercises. But things have changed significantly over the past decade. Isolated from the West, Russia has deepened its ties with China, including militarily. The Chinese People’s Liberation Army has participated in Russia’s strategic-level exercises, and bombers and fleets from both countries have started conducting joint patrols. In addition, the Chinese and Russian fleets conducted joint exercises in the Sea of Okhotsk in 2023 for the first time. Russia finally officially recognized the Chinese navy’s presence in the Sea of Okhotsk. In 2024, Chinese and Russian bombers conducted patrols in the Arctic Chukchi Sea, and the two countries’ fleets again conducted exercises in the Sea of Okhotsk.
Conclusion
Russian submarines are becoming more active in the northern waters of Japan, and there is a threat to critical underwater infrastructure in peacetime. In addition, China and Russia are stepping up their military cooperation in Japan’s northern waters. The resources of the Japanese-U.S. alliance are limited, and it may not be possible to respond to all threats from China, North Korea, and Russia.
The decision made during the Kishida administration to increase Japan’s defense spending to 2 percent of gross domestic product would alleviate some of the resource constraints. Kishida’s successor, Shigeru Ishiba, is expected to continue along the same path. Jet-propelled P-1s have replaced the P-3Cs that fly over my hometown, Matsudo, and they are even louder.
But this is not enough. Deterring several military powers in Eurasia at the same time is a very difficult task. There are limits to what the Japanese-U.S. alliance alone can do. In this sense, trilateral security cooperation between Japan, the United States, and South Korea and the framework between Australia, the United Kingdom, and the United States are the right approaches.
The challenge for the future will be to expand, strengthen, and interlink the security cooperation networks already in place. The idea of Japan and South Korea joining the Australia-U.K.-U.S. framework has been discussed for some time. Why not include Canada? Canada is located on both the North Pacific and North Atlantic Oceans. Japan has also expressed its intention to participate in the project to replace the Canadian Victoria-class submarines, and this is not only for commercial reasons. Another objective is to maintain the balance of power in the North Pacific. It is also possible that Japan and South Korea could share activities in the Tsushima Strait and the East China Sea, using the surveillance and warning capabilities of the South Korean navy and air force.
The naval game played out between Russia and the West gets harder every year. But there is no limit to the number of players in this game. This can work to the Western allies’ advantage.
Yu Koizumi is an associate professor at the Research Center for Advanced Science and Technology at the University of Tokyo. After receiving his master’s degree from Waseda University, Yu worked as an analyst for the Ministry of Foreign Affairs and as a think tank researcher, conducting research on Russian military affairs. Since 2020, he has also been vice chairman of ROLES, a diplomatic and security think tank established at the University of Tokyo with funding from the Japanese Ministry of Foreign Affairs. He is known to be a lover of cats and beer.
Image: RIA Novosti archive, image #326075 / Vitaliy Ankov / CC-BY-SA 3.0 via Wikimedia Commons
