Over 600,000 Chinese soldiers dispatched to invade northern Vietnam in 1979 ran into indomitable spirit and tenacity.

Fast asleep in her arms, Den’s baby chose the wrong time to wake up.

They were passing through a camp where Chinese soldiers were stationed.

Den covered the baby’s mouth to smother his crying. The child struggled, but she could not let him make any noise.

Only after the group had passed safely through the camp could she take her hand away from the baby’s mouth.

The baby had stopped breathing. He was just two months old.

Den quivered as she held her dead child’s body and held back the cries of anguish that threatened to erupt from her.

A small grave was dug and a tombstone hastily erected by the side of the road; and the group of people moved on.

It was a night lit faintly by stars.

It was one of many February nights in 1979, as the Sino-Vietnamese war raged at the border.

The group of people were trying to make no noise at all as they walked through the woods near the northern province of Cao Bang to try and reach Bac Kan Province, which had yet to become a war zone.

Rising tensions

Whoever traveled through the Chinese cities of Kunming and Nanning in the winter of 1978 would remember lines of vehicles packed with soldiers moving towards the south.

No one knew where they were going.

Some believed it was a military exercise.

At the same time, on the streets of Guangxi Province, the sight of soldiers in green outfits marching through the province’s many districts was not strange to locals. The puttering engines of numerous military vehicles present stirred up the dirt and a sense of foreboding.

Relationships between border guards on both sides had also turned sour after Vietnam regained independence in 1975, said Dinh.

"When we worked together, (Chinese guards’) faces didn’t seem all that welcoming. How they talked to us also differed from before," he remarked.

Dinh was not the only one noticing something strange was going on in the province.

Sam Thi Dong, a local militia member in Na Sac Town, said she saw people from the other side of the border moving the boundary posts of the two countries at night.

"Whatever we planted, they plucked it off. We tried to plant corn, they sent cows and buffalos to eat them all," she said.

Fellow resident Nguyen Thi Su recalled how local markets were littered with signs saying Vietnamese would be beaten if they were seen in proximity.

"The people of Na Sac were hated the most [by people from the other side of the border]. If you went to the market, and they knew you were from Na Sac, at best you were chased out, at worst beaten," she said.

Su’s village was home to over 40 families. When people noticed how the boundary posts were being moved by people from the other side, the whole village unilaterally decided to uproot themselves, abandon their fields and plantations, and relocate right next to the border to act as a living fence to protect the boundary posts. Their unyielding, adamant attitude earned them much hatred from the other side, Su said.

But the other side never gave up. Every night, they would fire flares for their people to scout around Na Sac. As such, local militia always had to be on guard and patrol the perimeters at all times. It was a constant tug-of-war.

To this day, Dong remembers the exchanges the people had innumerous confrontations:

"Your people are not as many as ours; your weapons are not as good as ours," the other side would taunt. 

"If you don’t fear death, come at us," this side would fire back.

The Battle of Cao Bang

The first round of cannons roared into life in the dead of night, one spring day in 1979.

Nong Thi Quyen, then 19, was living seven kilometers away from Ta Lung. She and her sisters were at a local movie theater.

Sixty kilometers away from where Quyen was, another movie show was also taking place in a Cao Bang Town. When the film ended and everyone prepared to go home, some people spotted flashes of light streaking across the jet-black sky.

Moments later, strange sounds, seemingly emanating from all directions, rumbled in the distance.

"It isn’t the rainy season, so how can there be thunder at this time?" Nong Van Ngan, 15, thought to himself. But like many others, he dismissed it and went home to sleep. 

With firepower ten times stronger than Vietnam, supported by artillery, the Chinese belligerents believed Vietnam’s border defense would quickly collapse and its neighboring towns seized within three days. And if they wanted, "Hanoi could be next within two hours," said Xu Shiyou, a Chinese general.

On the Vietnamese side, 600,000 soldiers were distributed across multiple fronts: Cambodia, Laos, the south and Hanoi. The border was defended by less than 60,000 troops.

China decided to attack on two fronts; one from the east and another from the west. Targets included Cao Bang, Lang Son, Quang Ninh and Lai Chau.

Specifically, 130,000 Chinese soldiers, approximately 25 percent of the nation’s total force, were dispatched to deal with Cao Bang alone, a province that stretched 333 kilometers along the border and had 634 boundary posts.

Official documents say that the war broke out on the morning of February 17, 1979. But in reality, it had started way earlier on the Cao Bang border. On February 16, Chinese forces had already seized the province’s Thong Nong District, before expanding towards Tra Linh and Ha Quang Districts.

When alarm systems, rudimentarily made with wood and bamboo, were sounded in Lung Pia Village of Ha Quang District, Sam Thi Dong woke up, grabbed her grenades and a bamboo staff in the corner of her house, ready for battle.

Her 5-year-old brother was wailing, woken up by thunderous explosions and blinding flashes of light in the night sky. Dong, her mother-in-law and six other siblings frantically hushed each other as they joined fellow villagers evacuating to a cave in the area. But Dong decided to stay.

"If you go now, will you ever make it back?" Dong’s mother-in-law tearfully asked her. But she had already made up her mind. Her father was also a militia member and her husband was a border guard in the province.

Dong took two sets of clothes, two extra blouses and a scarf. She had prepared them months before.

"If I die, no one will be able to come back home and bring me new clothes to change," she said. The 24-year-old woman was prepared to die when she set out.

Dong headed a squad with six other women. Most of them were not even 20 years old, and they all weighed less than 40 kilograms. In the dark, they walked two kilometers through woods and four kilometers on mountains, carrying a 60mm mortar and four ammunition boxes, to reach a military post in Lung Loong Village to get their weapons and prepare for battle at the Keo Li checkpoint.

Dawn came as soon as they reached their destination; sounds of explosions had died down by then. But the garbled, screechy voice of a scout soon came out of their walkie-talkie.

"They’re coming."

The six women immediately got into battle position. Dong and Lien steered the mortar, while the other four were tasked with calibration, aiming and reloading. About ten minutes later, a horde of soldiers spilled onto the battlefield from the other side, all armed to the teeth. Swarms of tanks accompanied them.

The girls started to throw in the mortar rounds, each weighing more than one kilogram, into the loading chamber. Once the trigger was released, the rounds were fired, and they followed a perfect arc trajectory before hitting the ground, sending dusty clouds and body parts scattering. So many were the enemy soldiers that no matter where you aimed, you would hit several at once. But they just kept coming.

Dong and her comrades stood their ground until noon, but the enemy hordes never stopped coming. Smoke and flame rose and bodies were piling up, and they did not even have a moment’s rest to take a sip of water.

Less than 100 meters away, Vietnamese soldiers and local militia were locked in battle, while backline forces evacuated citizens and transported the wounded out of the battlefield. Everyone’s mind went blank; the only thing they could do at that moment was to look ahead and keep shooting.

Two of the girls suddenly screamed in pain. Their clothes were soaked wet in crimson and drops of blood started to spill onto the ground. They had been hit by shrapnel in the head and the hips. Both fell to the ground. Four were left to hold the line.

Sea of Chinese soldiers

In the very first hours of February 17, 1979, Sergeant Ho Tuan heard voices of big crowds following a series of cannons while standing in an elevated sentry post at the Ta Lung International Border Gate in Cao Bang Province.

Looking through his heavy machine gun, Tuan felt his blood run cold as he saw waves of Chinese soldiers flooding through the border. Cannons cleared the way for tanks to advance, followed by the infantry. There were even drums and trumpets supporting the invaders. The Chinese army stretched out for kilometers, blocking the entire area in front of the border gate.

"There are so many of them, no need to aim, just keep shooting from above," Tuan told himself. But even as he kept shooting, the waves of Chinese soldiers kept coming.

In late 1950, during the Korean War, a war between North Korea (with the support of China and the Soviet Union) and South Korea (with the principal support of the U.S.), the Americans had been stunned to see waves of Chinese soldiers approaching the Yalu River, the natural border between the Korean peninsula and China. When one group was down, another group rose immediately. 

The American-South Korean union, with much more advanced weapons, could not hold that border. The strategy of using a sea of soldiers had once again succeeded. 

In his book "On Protracted Warfare" published in 1938, Mao Zedong, the Chinese communist evolutionary who became the founding father of the People's Republic of China, which he ruled as the Chairman of the Communist Party of China from its establishment in 1949 until his death in 1976, noted: "Weapons are an important factor in war, but not the decisive factor; it is people, not things that are decisive. The contest of strength is not only a contest of military and economic power, but also a contest of human power and morale. People necessarily wield military and economic power."

Then, in an interview with American journalist Anna Louise Strong in 1946, Mao said: "The atom bomb is a paper tiger which the U.S. reactionaries use to scare people. It looks terrible, but in fact it isn't. Of course, the atom bomb is a weapon of mass slaughter, but the outcome of a war is decided by the people, not by one or two new types of weapons."

After Mao’s death, his successor Hua Guofeng, followed that approach.

When the border war broke out with China wanting to “teach Vietnam a lesson” for overthrowing its ally Pol Pot and the Khmer Rouge in Cambodia, Mao’s military tactic was deployed again. 

Vietnam’s intervention in Cambodia, made after the Khmer Rouge’s repeated incursions and killing of Vietnamese citizens, heightened border tensions between Vietnam and China.

More Vietnamese soldiers were sent to Cao Bang Province.

Sergeant Ho Tuan had joined his comrades to celebrate Tet, the biggest holiday of Vietnamese people, a month earlier. In early February 1979, Tuan and other soldiers were ready to fight.

But the waves of Chinese soldiers that began pouring in at 4:30 a.m. on February 17 caught them off guard. 

After failing to hold the Ta Lung border gate, Tuan’s unit, Regiment 567, and others retreated 12 kilometers (7.45 miles), passing a series of hills, to the Khau Chia Pass.

The pass was the entrance to Cao Bang Town and if Chinese tanks could cross it, they only needed an hour to march into the town. 

The Chinese attacked the province from two opposite directions, the northwest and southeast. Their plan was to meet at Cao Bang Town. The attack that Tuan faced was from the southeast. 

"The Chinese had a system of attacking. They only shot early in the morning and rest at night," Tuan said.

When they wanted to attack an area, they first sent cannons in, fired a series of rounds, and then the infantry troops rushed in; and that was when the Vietnamese counter attacked, he recalled.

His entire regiment only had three KPV-14.5 heavy machine guns that were produced by the Soviet Union on order by Vietnam back in 1967 during the war against the U.S.

Every time the Chinese infantry approached, the Vietnamese side would fire nonstop, and soldiers had to use their drinking water to cool down the gun barrels. Tuan shot so hard that even the flash hider was blown away and he had to wait for his team to replace it.

Tuan and Regiment 567 spent 12 days keeping Khau Chia from falling into Chinese hands. They survived thanks to the plain rice that locals sent up to the pass. Very rarely, the rice was added with some salt and roasted sesame or fermented fish. 

There were days when some locals or militiamen were killed halfway along the pass as they transported rice up the hills to the soldiers. Late in the night, Vietnamese soldiers would crawl down those hills to pick up the rice that was covered in soil and dust. 

Girls from Tay and Nung ethnic minority communities that lived near the boundary line once used to cheer to welcome lines of trucks coming from the other side of that line. Those trucks carried rice and weapons that the Chinese government sent to support Vietnam during the war against U.S. in the Vietnam War, which ended in 1975.

But those were the days.

Just four years later, the tables had turned.

In 1979, the Tay and Nung people, who only knew to work on the farm, drink wine and have a good time, learnt to hold a gun. Those who could not fight took care of military logistics.

"If it were not for that help, all of us soldiers would have died," Tuan said.

Unable to cross Khau Chia for 12 days, the Chinese decided to change their tactics by moving around the pass and joining forces moving in the other direction, creating a pincer to crush Regiment 567. 

Tuan said he wished there were more Vietnamese soldiers there to help his team, but the majority of the nation’s armed forces were still fighting the Khmer Rouge in Cambodia.

Meanwhile, from the other direction, the Chinese had already attacked Cao Bang Town since February 24. They blew up every structure that stood higher than their knees. And when withdrawing from the town, they even destroyed a major 150m long bridge across the Bang River. All houses in the town were damaged, except for one where a picture of Mao Zedong was hung. 

Cao Bang Town was finally occupied and all connections were cut. Regiment 567 was totally isolated and had to fight on its own.

Millions without a home

Ten days after the war broke out on the northern border of Vietnam, Chinese troops approached Lang Son Town in Lang Son Province, a neighbor of Cao Bang and also of China, on February 27. 

Their purpose was to level to the ground every Vietnamese house near the border, and they did it. The Chinese destroyed almost every basic infrastructure and social facility, rendering 3.5 million Vietnamese people in the border area homeless. 

After the war, China announced 20,000 deaths while Vietnam counted more than 62,500. And there has never been an official announcement on specific damages suffered by both sides. 

If Chinese forces had managed to attack as far as Hanoi, the capital city of Vietnam over 280km (174 miles) south of Cao Bang, as their general Xu Shiyou used to threaten, they would have definitely faced the Vietnamese forces that had just returned from their Cambodian battles.

"Back then, Vietnam’s main forces had returned from Cambodia and been sent up to the northern border, to get ready to fight again. They were even prepared to surround and destroy all Chinese invaders in the area," said Nguyen Manh Ha, former director of the Institute of Vietnamese Communist Party History.

"But we decided to let China retreat instead of attacking them, for the sake of peace," he added.

The massive attack using a sea of people did create advantages for China at first. But once the Chinese got deeper into Vietnam’s soil, the unjustified, illegal war that they started gradually lost its steam.

One week after they expanded the attack on February 27, China declared on March 6 that it "would withdraw its troops in ten days."

Twelve days later, it completed the withdrawal. Returning after 30 days of clashes, China told the world that it "had achieved its war objectives."

The aftermath

40 years on, the Bang River has been in spate, on and off, season after flooding season, but a concrete block of the old bridge that was destroyed by China still lies on the riverbed. 

A new bridge lights up in five different colors today. The light show is a highlight of Cao Bang Town these days. And by that bridge, Ho Tuan has opened a small restaurant.

The Ta Lung, Tra Linh and Soc Giang border gates in Cao Bang, places that Chinese troops rushed through to invade Vietnam in 1979, have all been regulated as border-gate economic zones, with preferential treatment given to businesses since 2014.

The road from Ta Lung border gate to Cao Bang Town these days has become a major trading route between Vietnam and China. Trade turnover through Ta Lung hit more than $123 million last year, up 33.7 percent against 2017. 

The Martyrs' Cemetery in Quang Hoa District sits less than 10km from the Khau Chia Pass, and Tuan stops by to burn incense sticks for his comrades every now and then.

Of the 406 graves there, 250 belong to soldiers of Regiment 567. They were all killed in February, 1979. Many of them share the same death anniversary. 

Cao Bang folks rarely talk about the pain they suffered during that war. The memories are still there in detail; they easily recount them when asked. 

'Not afraid of China'

84 years old now, Nong Van Niem, a Tay ethnic minority man, has got into more than a few fights with Chinese people, barehanded and with weapons, to protect Soc Ha, a commune in Cao Bang Province’s Ha Quang District. 

Niem has unforgettable memories and feelings about the border war of 1979.

When a Chinese grenade killed his father, Niem was fighting with other militiamen to hold the sentry post of Soc Ha Commune.

He also remembers he had to spend one month and 20 days walking around his hometown and to Bac Kan Province, 150 km away, to look for the wife and children he had lost during the war.

Returning home from the post after a few days of fighting, Niem found his stilt house completely destroyed, his father dead, his wife and kids missing, his cattle gone and his family farm burned to ashes. 

A year after the war, Niem’s family was one of a few that returned to their hometown. Many did not dare to go back. 

But Niem could not stay in his former house. His family had to stay away for exactly ten years, waiting for authorities to remove all unexploded ordnance in the area. In 1990, when they were finally home, wild grass had grown to head height.  

In fact, the war did not end in early March, 1979. It lasted for a decade after, with Chinese forces continuously creating tension and disturbing the border area in order to pressurize Vietnamese forces to retreat from Cambodia.

And as recently as in 1996, when Vietnam started work on a checkpoint at the Soc Giang border gate, China came to mess it up. Niem, who was on his farm that day, rushed to the gate with other neighbors. 

"We’re poor, but we’re not afraid of China," Niem said, waving his hand towards the border.