Chinese customs officers in eastern Shandong province have seized 60,000 maps that 'mislabelled' the self-governed island of Taiwan, which Beijing claims as part of its territory. The maps, authorities said, also 'omitted important islands' in the South China Sea, where Beijing's claims overlap with those of its neighbours, including the Philippines and Vietnam.

The 'problematic' maps, meant for export, cannot be sold because they 'endanger national unity, sovereignty and territorial integrity' of China, authorities said. Maps are a sensitive topic for China and its rivals for reefs, islands, and outcrops in the South China Sea.

China Customs said that the maps also did not contain the nine-dash line, which demarcates Beijing's claim over nearly the entire South China Sea. The line comprises nine dashes which extend hundreds of miles south and east from its most southerly province of Hainan. The seized maps also did not mark the maritime boundary between China and Japan.

Authorities said the maps mislabelled 'Taiwan province', without specifying what exactly the mislabelling was. China sees self-ruled Taiwan as its territory and has not ruled out the use of force to take the island. However, Taiwan sees itself as distinct from the Chinese mainland, with its own constitution and democratically-elected leaders.

Tensions in the South China Sea flare up occasionally; most recently, encounters between ships from China and the Philippines led to accusations and denials of aggressive actions. The Philippines accused a Chinese ship of deliberately ramming a Philippine vessel, while Beijing claimed it was responding to unsafe maneuvers from the Philippine ship.

The Philippines and Vietnam are also particularly sensitive to depictions of the South China Sea in maps. In 2023, the Barbie movie was banned in Vietnam and censored in the Philippines for showing a South China Sea map with the nine-dash line.

The confiscation of 'problematic maps' by Chinese customs officers is not uncommon; however, the number of maps seized in Shandong easily eclipses past seizures. In March, customs officers at an airport in Qingdao confiscated 143 nautical charts with 'obvious errors' in national borders. Previous seizures in Hebei included two 'problematic maps' that misrepresented the Tibetan border.