How Should South Korea Respond to China's ‘Yellow Sea Project'?
The Yellow Sea is a shallow body of water, about the size of California, located between the Korean Peninsula and China. It is too narrow for South Korea and China to fully claim the 200 nautical mile Exclusive Economic Zone that each is allowed under the United Nations Convention on the Law of the Sea (UNCLOS).
In 2015, the two countries began discussions aimed at establishing their maritime boundary. These negotiations are ongoing, but little progress has been publicly reported. The most recent round of talks took place in Shanghai in November 2024, but many have questioned whether China is negotiating in good faith as it keeps building new structures in the Yellow Sea.
In recent months, there has been heated discussion about Beijing's 'Yellow Sea Project,' which many Koreans see as threatening South Korea's economic and security interests. These concerns are driven by China's history of coercive behavior and unilateral maritime expansion, and also renewed doubts about the U.S. commitment to its allies since the reelection of President Donald Trump.
China's Yellow Sea Project
Chinese President Xi Jinping has sought to make China a peer competitor for the United States, looking to erode and ultimately replace the U.S.-led international order with a new framework more conducive to Chinese interests. During the imperial era, China's sphere of influence extended across the whole of East and Southeast Asia, and Beijing is keen to restore such dominance. Toward that end, China's forces – its navy, air force, coast guard, and maritime militia – now routinely deploy high-powered water cannons, physical intimidation, and other harsh tactics to advance China's claims in the South China Sea, the East China Sea, and near Taiwan.
In the Yellow Sea, the North Sea Fleet of the People's Liberation Army (PLA), which operates under the Northern Theater Command, has already expanded its operational reach to waters east of the 124-degree-east longitude line, which has long functioned as the de facto maritime boundary between China and South Korea. This is fueling concerns that China's Yellow Sea Project is fundamentally about military expansion.
Although Chinese illegal fishing activities in the Yellow Sea have been common east of 124 degrees east, especially near the Northern Limit Line (NLL) between the two Koreas, Chinese military activities have not – until recently. The People's Liberation Army Navy (PLAN) has gradually increased its operations in the Yellow Sea, aligning with China's broader anti-access/area-denial (A2/AD) strategy. This seeks to constrain combined naval operations between South Korea and the United States, limiting them to freedom of navigation and overflight.
China is apparently attempting to convert the Yellow Sea into Chinese internal waters, having already claimed the Bohai Sea (the innermost gulf of the Yellow Sea) as an 'inland sea' since 1958. This clearly disregards the spirit and the principles of UNCLOS, which came into effect in 1997, and the further extension of such claims over the whole of the Yellow Sea should be strongly resisted.
Legal Status of the Yellow Sea
Unlike the South China Sea, where sovereignty disputes and strategic posturing have routinely escalated into diplomatic crises, the Yellow Sea remains a relatively well-managed maritime space, legally. While the overlapping EEZs between South Korea and China have so far prevented formal maritime boundary delimitation, both countries have worked around the legal limbo. For example, under the bilateral fisheries agreement signed on June 30, 2001, a Provisional Measures Zone (PMZ) was established to allow for joint management of fisheries, pending a final boundary settlement.
Overt naval clashes in the Yellow Sea between South Korea and China have largely been avoided. Instead, tensions have primarily manifested in two forms: North Korean provocations near the NLL, and frequent incursions by Chinese fishing fleets into sensitive maritime areas. To date, these incidents have rarely escalated into direct confrontations between the Republic of Korea Navy (ROKN) and the PLAN.
The relative stability of the Yellow Sea is supported by hotline agreements between naval units and between maritime law enforcement agencies, and also by multilateral mechanisms to avoid unexpected contingencies, such as the Code for Unplanned Encounters at Sea.
Strategic and Operational Significance of the Yellow Sea
The Yellow Sea holds immense strategic importance for the PLAN. The majority of China's submarines, both conventional and nuclear-powered, are built and launched from the Huludao and Dalian shipyards located in the Bohai Sea. These yards have recently been expanding rapidly to accommodate China's next-generation submarine programs.
The PLAN's North Sea Fleet, headquartered in Qingdao, is tasked with the operation of the Type 001 Liaoning aircraft carrier, China's first. It was originally designated for training purposes at its commissioning in 2012, and subsequently reassigned to full Carrier Strike Group capabilities in 2014. Since then, the North Sea Fleet has been training in the Bohai Sea, including flight deck take-off and landing operations with the Shenyang J-15, an indigenous fourth-generation, twin-engine strike fighter.
The North Sea Fleet is responsible for the building, testing, training, and operating of China's strategic nuclear submarines (SSBNs). It oversees the deployment of the Type 094 Jin-class SSBNs, which carry JL-2 and the new JL-3 submarine-launched ballistic missiles. It will also soon receive China's most advanced surface warships: Type 055 Renhai-class guided missile destroyers, and Type 054B new-generation frigates, both of them stealth vessels.
China's operational behavior in the Yellow Sea also reflects its growing discomfort with South Korea-U.S. joint exercises. After the ROKS Cheonan, a naval corvette, was sunk by a torpedo from a North Korean midget submarine in 2012, South Korea-U.S. combined naval exercises were planned for the Yellow Sea. Strong Chinese opposition led to a temporary relocation of the allied exercises to the East Sea (Sea of Japan), only to return later that summer to the southern waters of the Yellow Sea. In response, the PLAN conducted a large-scale live-fire exercise in the Yellow Sea, an early manifestation of its A2/AD doctrine.
Increasingly, China's North Sea Fleet has been deployed in missions and roles to protect the strategic importance of the Yellow Sea. Navigational harassment and coercive operations target the ROKN, the Korea Coast Guard (KCG), and South Korean scientific research vessels. China also frequently declares temporary no-sail zones under the guise of maritime law enforcement or research activities.
Taken together with China's stiff resistance to South Korea-U.S. combined naval exercises, as well as its increased security and military coordination with the Russian Pacific Fleet, it is clear that there has been a shift in China's perception of the Yellow Sea. It is not only central to China's active maritime defense strategy, but also the military front line to counter U.S. Navy operations.
China has escalated its 'gray zone' tactics in the Yellow Sea, and is increasingly blurring the lines between traditional military exercises and deliberate strategic messaging, with the Northern Branch of the China Coast Guard (CCG) assuming quasi-military roles in support of naval objectives.
Since 2014, Beijing has installed a number of unmanned buoys and semi-permanent maritime structures under the pretext of oceanographic research. Many of these are situated just west of the 124-degree-east meridian.
More provocatively, between 2018 and 2022, China erected two large-scale installations within the PMZ, ostensibly for aquaculture development, without consulting South Korea. Then in 2025, a steel framework over 50 meters in both diameter and height was observed in the PMZ, with more reportedly planned. All these structures are claimed to be fishing facilities, though some experts believe that they may be disguised oil rigs. Regardless, these actions constitute a violation of the 2001 Fisheries Agreement between South Korea and China.
Strategic Implications for South Korea's Maritime Posture
From a legal standpoint, China's operations in international waters do not explicitly violate UNCLOS, but they do represent a serious threat to South Korea's operational freedom in adjacent waters. Consistent maritime operational policies are necessary, since China appears to be calibrating the aggressiveness of its maritime operations according to the perceived assertiveness/passivity of South Korea's government. Administrations should seek to maintain a consistent national policy that guides Yellow Sea operations, regardless of political leadership transitions.
Internationalizing the Yellow Sea boundary issue could be counterproductive: exaggerating China's intentions could complicate negotiations and jeopardize previous gains in bilateral maritime cooperation. Handling South Korea's concerns directly with China will serve to preserve the integrity of existing bilateral arrangements in the Yellow Sea.
To that end, the ROKN should continue to conduct appropriate freedom of navigation and overflight operations west of 124 degrees east in the Yellow Sea. Beyond simply signaling South Korea's insistence on preserving its access rights under UNCLOS, such missions must be understood as essential to deterring North Korean infiltration. Existing bilateral mechanisms, such as the hotline systems between China and South Korea, should be adequate to convey such messages.
South Korea's intelligence, surveillance, and reconnaissance (ISR) capabilities in the Yellow Sea also need to be enhanced, both for deterrence and for situational awareness. The ROKN has been relying on its obsolescent P-3C Orion aircraft for both ISR and anti-submarine warfare targeting North Korea. It has now acquired P-8A Poseidon next-generation maritime surveillance aircraft, with greatly superior operational capabilities. As well as North Korea, ISR operations should be expanded to target PLAN and PLA Air Force movements in the Yellow Sea, particularly east of the 124-degree-east line.
South Korea's maritime law enforcement also needs to update its institutional structure. Unlike the CCG, which reports directly to the Central Military Commission and operates under military-style directives, the KCG is under civilian control, so it is restricted to law enforcement and lacks the legal mandate or logistical infrastructure to engage in paramilitary contingencies. In February 2025, the Korea Institute of Ocean Science and Technology sent a maritime research vessel to investigate a large Chinese installation on the seabed of the Yellow Sea. The operation was obstructed by PLAN-affiliated CCG vessels including speed boats, but only one KCG vessel was dispatched in response.
For South Korea, the significance of the Yellow Sea is nothing less than existential. The South Korean capital, Seoul, is connected to the Yellow Sea via the Han River, which flows through the heart of the city. Two of South Korea's three naval commands are located on the Yellow Sea, and the largest U.S. overseas garrison, Camp Humphreys, is within 10 miles of its shores. The Yellow Sea has now become the focus of concentrated Chinese military and paramilitary activity, and is rapidly emerging as a theater of geostrategic competition, joining the South China Sea, the Taiwan Strait, and the East China Sea. For South Korea, this shift requires a reorientation in both strategic posture and operational readiness.
Conclusion
The recent revelation of a large Chinese structure in the Yellow Sea is the latest manifestation of China's relentless efforts to shift the strategic balance in its favor, and to erode the military effectiveness of the U.S. and its allies. South Korea must do everything it can to resist China's Yellow Sea project, otherwise the strategic balance in the region will ultimately shift in China's favor, excluding South Korea and the U.S. from most of the Yellow Sea. Then Kyushu, Okinawa and ultimately Taiwan would be vulnerable, triggering a domino effect and laying a solid foundation for further PLA expansion in the Western Pacific.
Hashtags
Try Our AI Features
Explore what Daily8 AI can do for you:
Comments
No comments yet...
Related Articles
3 hours ago
Energy from the North? Japan Eyes the Promise and Perils of Alaskan Gas Investment
Among the barrage of executive orders that US President Donald Trump issued upon taking office in January 2025 is one titled Unleashing Alaska's Extraordinary Resource Potential, which proclaims the need to tap the state's natural resources, including liquefied natural gas, to rein in inflation, create jobs, correct trade imbalances, boost America's global clout, and counter moves by foreign powers to weaponize energy supplies. In conjunction with this policy, the Trump administration is urging Japan—under pressure from tough tariff negotiations—to invest in the Alaska LNG project, a costly plan to pipe gas across the state, liquefy it, and ship it to East Asian countries. Liquefied natural gas has a long history in Alaska. Japan's very first imports of LNG, back in 1969, were shipped from the state. But apart from the name, the Alaska LNG project being pushed by the White House has very little in common with its predecessor. Under the earlier plan, natural gas was extracted from reserves on the Kenai Peninsula on the south coast of Alaska, where it was processed into LNG and loaded onto ships for export. Total capacity was only about 1.5 million tons a year. Beginning in 2015, global LNG prices dropped as supplies increased and demand weakened, and it became increasingly difficult for Alaska to compete with other suppliers. In 2017, Alaska LNG's operations were shut down. The new Alaska LNG development project proposes to tap the North Slope gas fields on the Arctic Ocean coast in northern Alaska. A 1,300-kilometer trans-Alaska pipeline would transport the gas all the way down to the Kenai Peninsula, where chilling facilities would produce up to 20 million tons of LNG annually. Alaska Gasline Development Corp. (AGDC), the independent public corporation heading up the project (including construction of a natural-gas pipeline and liquefaction plant) hopes to begin shipping LNG around 2030. Alaska depends heavily on locally extracted natural gas for its own heating and industrial purposes, and the Kenai Peninsula's gas reserves have been dwindling, with supplies expected to run out sometime in the mid-2030s. For the state, therefore, development of the North Slope fields promises a new source of affordable energy for Alaskans, as well as significant revenue from exports. LNG Demand in East Asia In February 2025, the Japanese government released its Seventh Strategic Energy Plan, which calculates the outlook for energy supply and demand in 2040. Alongside its basic energy outlook, the plan incorporates an alternative scenario in which the official targets for adoption of nonfossil fuels (such as renewable energy and hydrogen) are not met. If the goals are achieved, demand for LNG in fiscal 2040 is expected to drop from the current level of 66 million tons (fiscal 2022) to somewhere between 54 million and 60 million tons. If the country falls short of the targets, though, it will need an estimated 74 million tons of LNG. In short, a certain level of demand for LNG is expected to persist through 2040. In the interim, the long-term contracts under which Japanese utilities and trading companies purchase LNG are coming up for renewal. New contracts will have to be signed to ensure a stable energy supply farther down the road, and Alaska LNG is one potential supplier. South Korea and Taiwan are in a similar position. Much like Japan, South Korea can only guess at the amount of energy renewables will be able to supply over the next 10 or 20 years. Taiwan, which shut down its last operating nuclear power plant in May this year, has adopted an energy strategy that calls for converting coal-fired plants to natural gas. All three countries have a clear need for LNG going forward, presenting a business opportunity for Alaska LNG. Geographical Merits Clearly, Alaska LNG enjoys the Trump administration's enthusiastic backing, but what are the relative benefits for Japan and its neighbors? The biggest advantage is probably geographical proximity. Japan already imports LNG from the United States, but those shipments originate in the Gulf of Mexico. The shortest route, through the Panama Canal, is about 17,000 kilometers. Moreover, because congestion has made it difficult for LNG tankers to transit the canal, the preferred route nowadays is around the Cape of Good Hope, a 29,000-kilometer trip. The southern coast of Alaska, by contrast, is only about 6,000 kilometers from Japan. The shorter distance and shipping time would mean lower transportation costs and more flexible delivery schedules. Shipping from Alaska is also attractive from the standpoint of safety of navigation. LNG from Qatar typically passes through the Strait of Hormuz and the Strait of Malacca before traveling north through the South China Sea. The Strait of Hormuz poses safety risks whenever the situation in the Middle East is unstable, and piracy continues to be an issue in the Strait of Malacca. China's increasingly assertive activity in the South China Sea, most of which it claims as its own territory, makes navigation problematic there. Shipping LNG from Alaska is a way of avoiding these safety risks. Cost Questions Remain But the Alaska LNG plan raises some serious questions centered on costs and lead time. Gas from the North Slope is inexpensive in and of itself, but the construction of a new gas treatment plant on the North Slope, a trans-Alaska pipeline, and a liquefaction plant on the Kenai Peninsula would incur enormous costs. An early estimate by the developer put the total expense at about $44 billion, but inflation has pushed up construction costs since then, and the challenges of laying pipeline through permafrost areas could add significantly to the expense. Any final decision must await a detailed, independent analysis, which will doubtless yield a higher price tag. For purposes of comparison, one might note that total investment in the Rio Grande LNG project, now under construction in Brownsville, Texas, is estimated at roughly $20 billion. To be sure, the two projects differ significantly in terms of the scale of construction and the kinds of expenses involved, but the comparison helps put the cost of the Alaska LNG project in perspective. The high initial investment required augments the challenges of financing the project and could also push up the selling price of the LNG thus produced. Bad Timing? The long lead time required for Alaska LNG to launch commercial operations is problematic on several counts. First, it could affect Alaska LNG's ability to compete with other LNG projects targeting Asian markets, including various US ventures, a Canadian project that began shipping LNG from the Pacific Coast in May 2025, and plans to expand production in Qatar. In short, Asian customers have multiple options for investing in and importing natural gas, and they will only choose Alaska LNG if it suits their needs with respect to timing and terms of sale. This is especially true in Japan, where most of the importers are private companies. In South Korea and Taiwan, where public corporations handle the importation of LNG, political considerations may play some role in purchasing decisions, but even so, buyers will have to decide whether the political benefits are worth the additional costs. Second, under the current timeline, Alaska LNG will not begin exporting until after the end of Trump's second term of office in January 2029. We have witnessed firsthand the policy U-turns that can result when a new president from a different party takes control in Washington. The next administration might well resurrect the environmental protections and climate-change policies that Trump has discarded, a shift that could spell trouble for Alaska LNG. Long-term business decisions require a measure of policy predictability, and in this key respect, the United States has become a high-risk country. The third issue with Alaska LNG's long lead time pertains to the target year for achieving net zero carbon emissions. Demand for LNG from Japanese and other East Asian importers is bound to decline sharply as the 2050 target year approaches. A 20-year LNG contract concluded in 2030 will last through 2049. If long-term contracts are needed to secure funding for the future, then it makes sense to begin export operations as soon as possible. Alaska LNG has very little time to spare. A Narrow Window of Opportunity Plans for tapping the North Slope's natural gas resources have been around for decades, but they have stalled repeatedly in the face of financial and political obstacles. Trump's executive order Unleashing Alaska's Extraordinary Resource Potential presents an unprecedented opportunity for the Alaska LNG project. But given Trump's term of office and the looming net-zero deadline, the window of opportunity is narrow. Ultimately, speed and cost will determine whether Alaska LNG can tap into the East Asian market. In terms of speed, the project needs to make concrete progress—meaning a final investment decision and initial construction—soon, while the political winds are still favorable. Otherwise, the project will lose momentum, and the market will be snapped up by competing LNG projects. The importance of cost considerations goes without saying. It would be foolish to overrate the value of Alaska LNG solely on the basis of geography. That said, if Alaska LNG can offer its product at a price comparable to that of competitors, then its geographical location becomes a powerful inducement, vastly increasing its chances of claiming a share of the East Asian market. (Originally published in Japanese on July 25, 2025. Banner photo: A liquefied natural gas tanker arrives at Futtsu Power Station in Futtsu, Chiba Prefecture, in February 2023. © Kyodo.)
7 hours ago
2 China Coast Guard Ships Enter Japan Waters off Senkakus
News from Japan Society Aug 4, 2025 11:47 (JST) Naha, Okinawa Pref., Aug. 4 (Jiji Press)--Two Chinese coast guard ships, again, intruded into Japanese territorial waters off the Senkaku Islands in Okinawa Prefecture on Monday, the Japan Coast Guard said the same day. The Haijing ships entered the waters off Taisho Island of the uninhibited islet chain in the southernmost Japan prefecture around 12:20 a.m. and approached a Japanese fishing boat, according to the 11th Regional Coast Guard Headquarters in the Okinawan capital of Naha. They are the same Haijing vessels that made similar moves in the waters on Saturday. China claims the Japanese-administered islands in the East China Sea, collectively called Diaoyu in Chinese. END [Copyright The Jiji Press, Ltd.] Jiji Press
NHK
9 hours ago
- NHK
Trump threatens sanctions, mulls envoy visit to Russia
US President Donald Trump says he may send special envoy Steve Witkoff to Russia ahead of the August 8 deadline he set for a ceasefire agreement with Ukraine. Speaking to reporters on Sunday, Trump said Witkoff "may be going" on Wednesday or Thursday. He has warned of sanctions if Russian President Vladimir Putin does not agree to a deal, saying "There will be sanctions, but they seem to be pretty good at avoiding sanctions." He added, "We'll see what happens." The sanctions could be applied to imports from countries that buy Russian products. Putin has said he will not agree to a deal unless Moscow's demands are met.
