The South China Sea covers almost 1.4 million square miles. It contains an estimated 11 billion barrels of oil. About $5.3 trillion worth of trade and more than half the world’s merchant tonnage passes through it. It contains some of the world’s most important fisheries.
And China claims basically all of it — much to the chagrin of Taiwan, Japan, Malaysia, Brunei, Vietnam, Indonesia and the Philippines.
Nearly 2 billion people live in countries that have maritime disputes in the South China Sea, and the U.S. has treaty obligations that could embroil it as well. Add to the mix nationalist rivalries and the battle to control the sea has become a major threat to the stability of the region.
While maritime border disagreements are nothing new, tensions are heating up as a number of nations take up aggressive actions. On May 7, the Philippines arrested a crew of Chinese fishermen in contested waters for poaching turtles. A day later, after Chinese ships rammed and fired water cannons at Vietnamese ships in a disputed area near the Paracel islands, a Vietnamese newspaper declared, “Vietnam will hit back if Chinese vessels continue ramming Vietnamese ships.”
The primary disagreements are over the Spratly islands, Paracel islands, Scarborough Shoal and the Diaoyu/Senkaku/Tiaoyutai islands — all of which are uninhabited, and most of which are routinely described as “large rocks.”
Territorial rows between China and its neighbors go back centuries, and the claims can be messy and complicated.
For example, the China-Japan-Taiwan disagreement over the Diaoyu/Senkaku/Tiaoyutai islands — eight islands that may sit amid large oil and natural gas deposits — goes back to at least 1895 with the signing of the Treaty of Shimonoseki, which ended the Sino-Japanese War and ceded Taiwan to Japan. Despite the fact that the disputed islands aren’t mentioned in the treaty, Beijing argues that it covers them implicitly and was therefore ceded back to China after the World War II. Japan says they surveyed the islands in the 19th century, deemed them to be owned by no one, took control of them and are therefore not part of its imperial expansion and so not covered by the treaty.
The islands are, however, explicitly mentioned in the 1952 Treaty of Mutual Cooperation and Security between the United States and Japan, which obligates the U.S. to defend the islands militarily.
Countries can’t even agree on what to call the body of water. Vietnam calls it the East Sea, and the Philippines even went as far as to change its name: In 1992, Philippine President Benigno Aquino ordered all official maps to call the sea the West Philippine Sea.
Countries and their citizens seem to be going out of their way to stoke tensions. In 2012, China released a passport that included a map of China’s maritime claims, which was swiftly denounced by the Philippines and Vietnam. Vietnam wrote to China to demand that the country "reverse their incorrect content," Luong Thanh Nghi, a spokesman for Vietnam's foreign ministry, told Reuters.
In 2012, 14 pro-China activists from Hong Kong, carrying Chinese and Taiwanese flags, sailed to the Diaoyu/Senkaku/Tiaoyutai and were detained by Japanese police. Their arrest sparked protests in China where Japanese military flags were burned.
The low-level clashes have continued, ramping up in May 2014 when China sent a $1 billion, 40-story-tall deep-water drilling rig to an area contested with Vietnam, an especially provocative move given that the oil company is state-owned.
A Vietnamese political analyst, Nguyen Quang A, quoted in The New York Times, tied the current conflict to centuries of fighting between China and Vietnam and suggested that tensions weren't going away anytime soon.
"Invasion is in their blood," he said, "and resistance is in our blood."