Illustrated by Baek Hyeong-seon

South Korean and Chinese maritime authorities were locked in a two-hour standoff in the West Sea (Yellow Sea) after Chinese personnel blocked a South Korean research vessel from inspecting a large steel structure Beijing had installed in a disputed maritime zone, sources familiar with the matter said.

The confrontation occurred on Feb. 26, when South Korea’s Korea Institute of Ocean Science and Technology (KIOST) deployed its research vessel RV Onnuri (1,422 tons) to examine the structure, located in the Provisional Measures Zone—a contested area where the exclusive economic zones (EEZs) of both nations overlap. South Korean intelligence had earlier detected China’s construction of a mobile steel structure measuring over 50 meters in both height and diameter. Beijing had previously installed two similar structures in nearby waters between April and May 2024.

As RV Onnuri approached, four Chinese personnel in two rubber boats intercepted the vessel, brandishing knives and preventing South Korean researchers from deploying inspection equipment, the sources said. In response, South Korea’s coast guard dispatched patrol ships, resulting in a tense standoff with Chinese maritime authorities that lasted for two hours.

Experts say installing structures in the Provisional Measures Zone without mutual consent constitutes a violation of bilateral agreements. However, China has reportedly claimed the facility is a fisheries-related installation.