Yellow Sea flashpoint in China’s power play

It’s part of a broader campaign by Beijing as it asserts its intention to prevent its neighbours, as well as the US, from challenging its influence over the region.

China’s first domestically built aircraft carrier, the Shandong, sails into Hong Kong harbour on Thursday. AP Photo/Chan Long Hei

One day in February, a South ­Korean research vessel ­approached a set of unusual structures planted by China in the middle of the Yellow Sea, the narrow body of water that separates the two countries.

Two large Chinese Coast Guard ships and three Chinese boats quickly blocked the South Korean ship’s path. The passengers on the small Chinese boats wielded knives to force the ­Koreans back.

After two hours, the South ­Korean ship turned back, unable to learn more about the mysterious installation that sat about 370km from the country’s coast: a yellow aquaculture cage placed next to a refurbished multistorey oil rig, complete with lifeboats and a helipad.

It was the latest of a series of Chinese provocations in the Yellow Sea, including incursions into South Korean territorial waters and airspace, and the placing of 13 buoys that some experts say could be used to gather intelligence.

The Yellow Sea is emerging as the newest flashpoint in a broader campaign by Beijing as it asserts its intention to prevent its neighbours, as well as the US, from challenging its influence over the region.

The provocations also come as China claims all of the South China Sea, a vital waterway for global trade. Chinese jet fighters have increased sorties near Taiwan and last month they tailed Japanese air patrols during exercises. Beijing also launched live-fire drills off the coast of Australia earlier this year.

But friction in the Yellow Sea is especially alarming because of its strategic importance in any future US-China conflict over Taiwan. Beijing would likely need free ­access to the waterway to deploy its naval and missile firepower during any attempt to seize control of the island.

The largest overseas US military base, home to 28,500 service personnel, sits 16km inland from the Yellow Sea in South Korea.

Tens of thousands of US troops are also stationed 800km away in Japan. The Trump administration has signalled that US troops from both countries could be deployed in a clash with China over Taiwan. A stepped-up Chinese presence in the Yellow Sea could limit the ability of the US to manoeuvre in such a conflict.

A large portion of Beijing’s naval capabilities, as well as key missile launch sites, sit on China’s side of the Yellow Sea, making them vulnerable to attack from US forces in the Indo-Pacific region.

Over the last couple of years, China has steadily escalated pressure on Asian countries with close ties to the US. Incursions into South Korean waters by Chinese warships have tripled since 2017, South Korea’s military says, while aircraft intrusions have surged.

In March, Beijing issued a ­directive calling for more assertive behaviour in South Korea’s territorial waters, according to a senior Taiwan security official, citing local intelligence. Beijing is also seeking to build more maritime structures there.

“China is putting pressure on yet another US ally, hoping to weigh down the allied ability to push back,” said Brian Hart, deputy director of the China Power Project at the Centre for Strategic and International Studies in Washington.

The Yellow Sea is so narrow that China and South Korea’s exclusive economic zones overlap. More than 20 years ago, Beijing and Seoul created the so-called Provisional Measures Zone, which created rules for policing ­illegal fishing and conducting marine conservation activities.

Fast forward two decades and the PMZ is the site for near-daily provocations by China, according to the South Korean military. It says Chinese warships intruded in South Korea’s territorial waters 330 times in 2024, tripling from 2017, according to the military.

Recent South Korean data shows 130 Chinese aircraft entered its airspace in 2023, more than double the number from the previous year. Many of the Chinese flights were over the Yellow Sea, prompting South Korea to scramble its jets in response.

In May, Beijing jolted Seoul by declaring a no-sail zone in the PMZ. It then carried out unprecedented drills in the Yellow Sea with the Fujian, the country’s most advanced aircraft carrier. In response, South Korea deployed its navy to observe and gather intelligence on the exercises.

The cluster of Chinese structures dotting the sea has rattled officials in Seoul. The fishing cage and the oil rig at the centre of February’s incident are located on the western side of the shared PMZ, close to Chinese land. Beijing has repeatedly said they are for maritime research.

Analysis by the Centre for Strategic and International Studies found the rig could have military as well as scientific uses. “Concerns that the platforms may be dual-use for purposes of ­advancing China’s creeping jurisdictional presence aren’t unfounded,” it said.

As for the buoys, which China asserts are for meteorological ­observation, South Korean politician Yu Yong-weon has suggested that they are clustered close together in order for China to control the area rather than collect scientific data.

China has a history of building maritime structures that are used to assert its territorial claims. It has turned reefs in the South China Sea into artificial islands, equipping them with radar systems and air strips. “China always has a dual purpose for everything,” said Derek Grossman, a former Pentagon official who worked on Indo-Pacific security issues.

Chinese and South Korean ­officials met on Tuesday for bilateral talks. South Korea’s Foreign Ministry, in a brief reference, said the two sides had discussed the situation in the Yellow Sea. China made no mention of the sea and said it exchanged views with South Korea on issues of common concern.

The Wall Street Journal