On a faded notice pasted to the padlocked doors of the Lotte Mart superstore in Jiaxing, China, a date can still be read: March 6, 2017 — when the store was ordered to "temporarily" close over alleged fire safety issues.

The shuttered entrance and flapping notices are a blunt reminder of how South Korean businesses have become unwitting victims in a year-long diplomatic standoff between Beijing and Seoul.

Last September, Chinese President Xi Jinping warned his South Korean counterpart that bilateral ties would suffer if Seoul did not properly handle China's opposition to the planned deployment of a U.S. anti-missile defense system in South Korea.