My colleague Adam Taylor unpacked the recent events that reportedly spurred thousands of Vietnamese protesters to ransack foreign-owned factories in the environs of Ho Chi Minh City. Waving Vietnamese flags and chanting nationalist slogans, the demonstrators were enraged by China's latest aggressive act: the placement of an oil rig  not far from Vietnam's coast, in waters contested by both Beijing and Hanoi.

"Our patience has limits," a 74-year-old war veteran told Agence France-Presse, outside the Chinese embassy in Hanoi. "We are here to express the will of the Vietnamese people to defend our territory at all costs. We are ready to die to protect our nation."

Conspicuously, the Vietnamese government--one which routinely stifles dissent and muffles civil society at home--appears to have sanctioned some of the protests. The country's Communist rulers walk a delicate tightrope, compelled both to manage a pivotal relationship with its larger, far more powerful northern neighbor, while also reckoning with the burgeoning anti-Chinese sentiments of its population.

China isn't making Vietnam's hand any easier to play. In recent years, the longstanding Sino-Vietnamese rivalry over disputed archipelagos in the South China Sea has flared, as an increasingly assertive China expanded its navy and pushed its maritime claims.

The tensions between the two countries belie a shared ideological and cultural past. For centuries, parts of Vietnam existed under the suzerainty of Chinese dynasties. By the mid 20th century, as the Vietnamese struggled to overthrow French colonial rule, Vietnam's revolutionaries received aid and support from Chairman Mao Zedong's People's Republic of China.

But things turned after the conclusion of the U.S.-Vietnam War, when the Vietnamese moved solidly into the Soviet camp, antagonizing Beijing, which had warmed to the United States and also helped prop up Pol Pot's murderous Khmer Rouge regime in neighboring Cambodia. When Vietnam stepped in at the end of 1978, overthrew the Khmer Rouge and effectively ended the hideous Cambodian genocide, China found reason to retaliate.

The brief, bloody war that followed in 1979 -- then Chinese leader Deng Xiaoping said he wanted to teach the Vietnamese "a lesson" -- achieved little but a ruinous loss of life. In the first few days of combat alone, some 4,000 invading Chinese soldiers, thrown at Vietnamese lines in "human waves," were killed. Tens of thousands died on both side, with both Beijing and Hanoi claiming Pyrrhic victories.

It's a conflict the Chinese, in particular, try to forget. Here's the excellent Tea Leaf Nation blog on how China's official media organs marked the 35th anniversary of the conflict earlier this year:

Recent articles on Vietnam in People’s Daily, the Chinese Communist Party mouthpiece that essentially declared war on its southern neighbor with an editorial on Feb. 16, 1979, lacked any mention of the conflict. A Jan. 21 People’s Daily article about anti-Chinese feelings in Vietnam avoided mention of any armed tussle between the two countries in the late 20th century, instead blaming the negative sentiment on Vietnamese’s “sour” and “contradictory” attitude towards historical Chinese cultural influences and current economic dominance. Another People’s Daily piece from Feb. 13 profiled the bustling town of Mong Cai on the eastern Chinese-Vietnamese border, which cleared over $2.6 billion worth of import and export goods in 2013, without mentioning that it was the scene of fierce fighting 35 years ago.

Meanwhile, according to the BBC, Vietnam's state press has revived the story of the 1974 clash between Chinese and South Vietnamese forces over the Paracel Islands after a long silence. At the time, China sank a South Vietnamese ship and killed dozens of Vietnamese sailors and soldiers. But it took the communist government in Hanoi decades to view that defeat as a national sacrifice. Beijing retains de facto control of the Paracels and it's from there that the Chinese justify the current territorial positioning of the oil rig.

In Southeast Asia, as a whole, there is a growing resentment toward perceived Chinese imperialism, with governments such as those in the Philippines taking largely unprecedented, confrontational stances against China. Vietnamese anger toward China is also fueled by a sense that Chinese interests have overwhelmed the Vietnamese economy: some of the most significant organized protests have surrounded the opening and expansion of Chinese bauxite mines in the country.

In the past, the Vietnamese would likely find subtle ways to cope with Chinese pressure and local resentment, but signs point to a new, stiffer resolve. To present something of a deterrent threat to the China PLA Navy, Vietnam is building up its submarine fleet, enlisting both Russian and Indian help. Vietnam's state press has encouraged their fishing fleets to challenge rules over access set up by Chinese administrators of the Paracels.

It's an environment primed for provocation -- and leading experts are worried. "We can anticipate several more months of high tensions," says Ian Storey, a security analyst at Singapore's Institute of Southeast Asian Studies, in an interview with Reuters. "I believe [that] could lead to the most serious crisis in Sino-Vietnamese relations since the 1979 border war."