The Economist explains

How the “nine-dash line” fuels tensions in the South China Sea

China has co-opted a cartographic mistake to bully its neighbours

AT SEA - DECEMBER 13:     A Filipino fisherman operates around Scarborough Shoal while a Chinese Coast Guard ship on December 13, 2016 in Scarborough Shoal, South China Sea. Scarborough Shoal lies within the exclusive economic zone (EEZ) of the Philippines. However, it is claimed by not only the Philippines but also China and Taiwan. In July, the Permanent Court of Arbitration, based in The Hague, denied China's claim over the South China Sea. As for Scarborough Shoal, the court said that China is infringing on the Philippines' traditional fishing rights. China has refused to accept the court ruling. Tensions heightened in the South China Sea on December 15 when a Chinese naval vessel seized a U.S. Navy underwater drone in an area.  (Photo by The Asahi Shimbun via Getty Images)
Image: Getty Images

CHART THE course of Chinese coastguard ships in the South China Sea and a pattern emerges. The boats’ patrols often follow a U-shaped route that stretches over 700 nautical miles from China’s coastline, encircling most of a sea that plays an outsize role in global trade and security. This path is the “nine-dash line”. China claims everything inside it as its own, ignoring protests from neighbouring countries. Last year its coastguard spent longer patrolling key reefs along the line than ever before. China’s assertiveness in enforcing this claim is perhaps the biggest obstacle to calming tensions in the South China Sea. How did this line become so important?

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