The Sino-Russian Joint Statement in May 2024 generated considerable media excitement. In the agreement, Moscow pledged its support to Beijing in conducting constructive dialogue with North Korea to allow Chinese vessels navigation through the lower reaches of the Tumen River. This seemingly innocuous agreement could have serious geostrategic consequences, as Chinese access to the Tumen estuary may grant direct maritime passage into the Sea of Japan and potentially a new littoral naval base. Throughout the Cold War, Soviet naval forces operating from Vladivostok repeatedly challenged U.S. naval forces, turning the Sea of Japan into a frontline of U.S. containment strategy. A Chinese presence in the Sea of Japan could bolster Beijing’s increasingly confrontational assertions in the East and South China Seas by opening a new frontier to subvert U.S. maritime dominance. Such developments would serve to divert and stretch U.S. and allied forces from Taiwan and bring China one step closer to neutralizing the first island chain.
Currently, Chinese ships can only navigate the Tumen up to Fangchuan village, located 17 kilometers from the Sea of Japan. The remaining stretch of river is controlled by Russia and North Korea, leaving China’s Northeastern provinces landlocked. Chinese access to the Tumen and the Sea of Japan has been historically denied since the cession of the Tumen River estuary by the Qing Dynasty to Imperial Russia following the 1860 Treaty of Peking. Despite Beijing’s arguments that it had retained the rights for navigational access of the estuary, Chinese ships have required strict permission to sail the Russo-North Korean sections. Furthermore, a 7-meter-tall Soviet rail bridge between Russia and North Korea physically bars larger ships from entering the Sea of Japan.
In recent years, China has desired riverine passage to the Sea of Japan to revitalize the economy of its deteriorating Northeast provinces and enhance Arctic shipping connections to further its Polar Silk Road strategy. Accordingly, China believes that its resource-rich rust belt could bring mutual industrial and economic benefits throughout Northeast Asia if direct sea lanes are established across the Sea of Japan, connecting the coastal cities and ports of South Korea and Japan to mainland Asia. Beneath the talk of mutual interests and economic development, however, China also reportedly harbors ambitions for a naval base on the Tumen to project maritime power and influence into the Sea of Japan.
Resultingly, the news and prospect of China gaining maritime access to the Sea of Japan rattled many observers, fearing that it could overturn the strategic balance of the region. Analyses ranged from concerns of expanded Chinese Coast Guard activity based out of the Tumen to possibilities of a new naval facility to enable the Chinese Navy unfettered access to the Arctic.
Indeed, if Beijing gains direct access to the Sea of Japan, the Chinese Navy will be able to bypass the geostrategic Tushima Strait chokepoint and threaten the Japanese home islands directly to further burden U.S. naval power. Chinese naval or coast guard vessels could also attempt to agitate bilateral relations between Japan and South Korea by sailing near the disputed Liancourt Rocks to create rifts amongst U.S. allies. Such an incident has already occurred when Chinese and Russian bombers entered the disputed airspace over the islands in 2019, resulting in a diplomatic row between Seoul and Tokyo. These fears are not unfounded, as evidenced by recurring joint Sino-Russian naval exercises in the Sea of Japan or the 2024 joint bomber patrols in the Northern Pacific nearing Alaska, indicating Beijing and Moscow’s desire to challenge Washington’s strategic interests in the Asia-Pacific. Nevertheless, despite the apparent agreement between Moscow and Pyongyang to grant China unbounded navigation of the Tumen, it remains skeptical and unclear if Beijing will ever realize its dreams of unlimited access to the Sea of Japan.
The first major obstacle to Chinese plans to access the Sea of Japan originates from the Tumen River itself, which is shallow and unsuitable for commercial vessels in its current state. According to a report from the DASC, a think tank affiliated with the Dalian Maritime University, the river is barely navigable downstream from Hunchun, of which 55.9% of the estuary is impassable due to accumulated silt. Resultingly, only small boats under 50 tons can navigate the river.
If China wants to make the river navigable and connect the nearby riparian Hunchun city rail port to the Sea of Japan, nearly 100 kilometers of waterway from Hunchun to the sea would need to be deepened and widened, and several locks constructed. Furthermore, another 50-kilometer-long underwater channel would need to be dredged from the mouth of the Tumen estuary into the seabed to enable vessels unobstructed access to global shipping lanes.
Projected costs for the work are expensive, with expenses estimated to rival that of the Pinglu Canal, which needed over $10 billion in investments. Riverine access to the open ocean will be hard and costly to maintain as the Tumen’s lower reaches consistently freeze over during winter. Spring and summer floods also deposit large amounts of sediments into the estuary, requiring expensive yearly dredging to keep the waterway open. The immense projected costs and difficulties in making the Tumen navigable make the project unattractive compared to the established alternatives of using nearby North Korean or Russian ports.
The second major roadblock to Chinese ambitions comes from its very partners, Russia and North Korea, who appear reluctant to give Beijing access to the Sea of Japan. Notwithstanding Russia’s promise to guarantee Chinese navigation rights of the Tumen estuary in May 2024, Russia and North Korea agreed to construct a new highway bridge over the Tumen during Vladimir Putin’s state visit to Pyongyang in June 2024. Technical specifications of the planned bridge remained unknown, but once construction commenced earlier this April, it became clear from official architectural renderings that the new overpass would approximately be the same height as the pre-existing railway bridge. As a result, the passage of large vessels or cargo via the Tumen to the open sea remains physically blocked.
State-run Chinese institutions, such as the Academy of Ocean of China, had previously expressed hopes that the pre-existing bridge could be demolished and rebuilt, going as far as suggesting that China fund the costs of this endeavor. However, the low height of the new highway bridge makes it abundantly clear that Moscow and Pyongyang are unwilling to accommodate Beijing on this issue. The reason for this sidelining could stem from Russia and North Korea’s longstanding distrust of Chinese ambitions. For instance, recently leaked FSB documents revealed serious fears of Chinese intelligence infiltrating the country, including trepidations that China would attempt to annex the Russian Far East. As a matter of fact, related fears arose in 1995 during Sino-Russian border negotiations, when opponents of Russian territorial concessions cited the possibility of Beijing building a major oceanic port and naval base on the Tumen to militarily threaten Vladivostok.
In a similar vein, Kim Jong Un has reportedly distrusted China since 2012, when Chinese leadership did nothing to prevent or inform Pyongyang of a potential regime change attempt. Further Chinese actions, such as its disapproval of North Korea’s nuclear weapons program and support for international sanctions, served to anger and alienate Pyongyang. Although China has attempted to repair its strained ties with North Korea since 2018, bilateral relations have allegedly become frosty following the formation of the North Korea-Russia defense pact.
Regardless of Sino-Russian declarations of a “no limits” strategic partnership or the trilateral China-Russia-North Korea display of unity during China’s victory day parade, Beijing’s Tumen navigation issue demonstrates the uneasy nature of this alignment. Whilst military and economic bonds amongst the “axis of upheaval” have gotten stronger, it demonstrates the fundamental distrust amongst partners and unwillingness to compromise even a fraction of their national interests. Indeed, if China gained open access to the Sea of Japan, it could bring greater economic opportunities to both Russia and North Korea, while militarily it could stretch regional U.S. naval capabilities by opening a new front for pressure. Such actions would undoubtedly serve to further Beijing, Moscow, and Pyongyang’s mutual interests against the U.S. and its regional allies. Nevertheless, Russia’s anxiety towards Chinese interests in its eastern provinces and North Korea’s antipathic perception of China as a “nemesis” reveal the constrained nature of the current alignment. As such, long-term coordinated designs in Northeast Asia against the U.S. and allied nations will most likely remain elusive for the time being.
Had the enormous costs of opening the Tumen for navigation not already dissuaded Beijing, then the geopolitical rivalries and the construction of the new highway bridge undoubtedly would have put a hard stop to existing plans. The current reality suggests that Chinese ambitions for the Sea of Japan will remain nothing more than a distant dream—at least for the foreseeable future.
