Although some of the factories were owned by companies from Taiwan and South Korea, they were not thought to be the real target of the protesters' anger.
That prize belongs to China and its now-infamous "nine-dash line."
The protests were sparked when Beijing deployed an oil rig in waters claimed by Vietnam on May 1. The Haiyang Shiyou 981 now sits about 70 miles inside the exclusive economic zone (EEZ) that extends 200 miles from the Vietnamese shore as part of the 1982 U.N. Convention on the Law of the Sea.
The problem is that China doesn't really care about Vietnam's EEZ. What matters to Beijing is the nine-dash line: A loosely-defined maritime claim based on historical arguments which China uses to claim much of the land mass in the South China Sea. That nine-dash line (which, as the name implies, looks like nine dashes on a map) runs remarkably close to Vietnam's shoreline, and though its nature is imprecise, Beijing seems to claim economic rights within the line.
Beijing has been using maps featuring the line since the 1950s, but it was only in the late 1960s that the issue really became a problem, after a U.N. report concluded that the area possibly had large hydrocarbon deposits.
It has caused big rifts between China and Vietnam, which have a complicated relationship at the best of times. In 1974, after attempts by the South Vietnamese government to expel Chinese fishing ships, the Chinese navy seized the historically unoccupied Paracel Islands after a short battle and has held them since, despite a 1988 skirmish that left more than 70 Vietnamese soldiers dead. China later built a city on the largest island in the archipelago, long claimed by Vietnam, and it appears to claim an EEZ around the islands which includes the location of the Haiyang Shiyou 981.
The nine-dash line isn't a problem just for Vietnam. Going by its U-shaped curve, the larger group of the Spratly Islands also falls within Chinese territory, despite competing claims by the Philippines, Brunei, Malaysia, Taiwan and Vietnam. The 200 or so mostly uninhabitable islands and rocks also are thought to be rich in oil and gas. In addition, China has a serious maritime dispute with Japan in the East China Sea.
Vietnam and China had shown some signs of rapprochement in recent years, signing an agreement in 2011 aimed at solving the South China Sea disputes, and Hanoi had already offered the waters near where the rig is sitting for exploration by energy companies. However, with the arrival of the oil rig – said to have cost $1 billion to produce – relations are looking their worst in years. The timing of the move is worth noting, coming shortly after President Obama's trip to Asia and just before a recent meeting of the Association of Southeast Asian Nations.
It's a big problem for Vietnam, which is largely impotent in any battle against China. As a recent Washington Post editorial noted, Vietnam lacks strong military ties with the United States and is ruled by a powerful Communist Party that includes a strong pro-Beijing faction. It can't hope to compete with China's navy, and Chinese President Xi Jinping has made it clear that he would use military strength to protect what he views as Chinese territory: A graphic example of that is the videos posted online last week that appeared to show the oil rig's Chinese escort ramming and shooting water cannons at Vietnamese boats trying to stop the flotilla.
The protests within Vietnam seem to be a result of that impotence. Although unauthorized protests are rarely tolerated in Vietnam, the anti-China demonstrations seem to have the government's blessing. The AP reports that signs have been handed out at some protests that read: "We entirely trust the party, the government and the people's army."
It is unclear whether the violence Wednesday morning was part of the plan, however, and Hanoi may find itself torn between two difficult choices – facing the military and economic wrath of China or its own increasingly furious domestic audience.
CORRECTION: An earlier version of this post incorrectly described the basis for China’s territorial claim there. China asserts sovereignty over land features in South China Sea that lie within a so-called nine dash line on Chinese maps; it does not assert a claim to all waters within that line. China’s assertion of a right to deploy the oil rig in its current location appears to be based a Chinese claim to the nearby Paracel Islands, not the waters themselves. The article also incorrectly stated the islands were historically unoccupied; in fact, they were once sparsely populated.