Regulars of the Jianba barbershop in this southern city recently found it shuttered, with a curious note taped to the door.

Dear customers, I got a call from my daughter yesterday. I have been away from her so long, she doesn’t even know how to call me ‘Daddy’ anymore . . . . I beg you for a week off to visit my family.

The letter, photographed by a passerby, was posted on the Chinese equivalent of Twitter and quickly went viral. It reflected a growing angst in this country over “left-behind children.”

More than 61 million children — about one-fifth of the kids in China — live in villages without their parents. Most are the offspring of peasants who have flocked to cities in one of the largest migrations in human history. For three decades, the migrants’ cheap labor has fueled China’s rise as an economic juggernaut. But the city workers are so squeezed by high costs and long hours that many send their children to live with elderly relatives in the countryside.

The barber who posted the note, Wu Hongwei, and his wife, Wang Yuan, had left their daughter with her grandparents in a remote village when she was 9 months old. The couple thought the 340-mile distance was a challenge they could overcome.

Every day, they phoned and told the little girl that “Mommy loves you” and “Daddy misses you.” They taped photos of themselves on the concrete walls of her room at her grandparents’ house.

But after almost two years, they have come to a stark realization.

“We are complete strangers to her,” Wu said.

A tough decision

Wu, 24, left the tiny village of Zhaishi in the craggy mountains of Hunan province eight years ago. Staying would have meant back-breaking labor for just $3 a day — when work could be found.

The tall, lanky young man bought a bus ticket to the city of Zhangzhou, where his uncle took him on as an unpaid barber’s apprentice. Wu then moved to Zhuzhou, where he got a job pulling in $500 a month.

It was in that city that Wu met Wang, a woman with an infectious laugh. Wang’s friends called her “Baozi,” or steamed bun, because of her chubby cheeks. The barber wooed her with his guitar and folk songs. And, for a while, life in the city seemed full of possibilities for the newlyweds. They had their daughter, Beibei, in 2011.

To take care of the baby, Wang, 33, quit her job selling cellphones. Her husband worked extra hours, cutting hair from morning to 11 p.m.

At first, they managed to get by. They kept up the $100-a-month rent. Like many migrant workers, Wu had to help support his peasant parents; $170 a month went to them.

But then their baby was weaned and needed formula — an expensive product in China, where parents distrust cheap ­local brands, which often turn out to be tainted. Even average-
quality Chinese baby formula sold for at least $100 a month, a fifth of the couple’s monthly income.

“There was no choice. We both needed to keep working,” said Wang, whose parents were too sick to help.

So, in May 2012, the couple made the journey to Wu’s village — a grueling 14-hour trip via bus, two trains and a motorcycle — and gave the baby to his parents.

It seemed like an obvious solution. Almost every young couple from Wu’s village had done the same so they could keep their city jobs. It even allowed Wu and Wang to put aside a little money toward their dream of opening their own barbershop.

The couple comforted themselves with the notion that Beibei might be better off in the countryside.

“We don’t want her to endure the pressures of the city life, to think always of material things,” Wang said. “We want her to be happy.”

Meaning of ‘Mom’ and ‘Dad’

The first few months without Beibei were excruciating.

“I went to sleep hugging the little outfits she left behind,” Wang said. “I cried constantly.”

Her husband, a quiet man, focused on his job, finishing each $2.45 haircut so he could send money home.

Three months after dropping off their daughter, the couple returned to the village, eager to visit. As soon as they walked through the door, Beibei hid from them.

“Whenever we tried to hug her, she screamed and clung to Grandma,” Wang recalled.

At one point, the couple asked their daughter to point out Mom and Dad. She ran to the photos on the wall, not to them.

Around her parents, Beibei, a playful girl who often spends her days singing to the mountains, grew painfully quiet.

She didn’t understand her mother’s Chinese, having learned the ethnic dialect of the village. The few words the little girl could say, Wang couldn’t make out.

“She loves Grandma the most,” said Wang, who has tried not to feel envious. “When she’s hurt, she runs to her.”

During the trip, the couple went to a nearby town and bought toys and sweet steamed buns to try to win Beibei over.

To hold her, they waited until her grandmother lulled Beibei to sleep, then sneaked into bed and replaced the older woman’s arms around their daughter with their own.

“Those few hours at night,” Wang said, “were precious.”

By the end of their second visit, last December, they had finally taught their daughter to say “Mom” and “Dad.”

“But the way she says ‘Mama,’ it’s nothing more than a name to her,” Wang said recently. “There is a person named Mama, but it has no meaning.”

Then, one day this past fall, Beibei’s grandparents called Wu and Wang to tell them how some relatives — a newly married couple — had visited, bringing presents for Beibei. When the little girl saw the young couple bearing toys and sweets, she called them “Mom” and “Dad.”

“It cut us deeply,” Wang said.

Wu and his wife had finally pooled enough money to open their barbershop in a closetlike space off a city road. But when they heard the story, they decided to head for the village.

On their way out, they hastily stuck the note on the door.

‘It’s not too late’

Many people who saw the note online left comments bemoaning the brutal nature of China’s modern economy. “To make a living, people have paid too much,” one said.

“I burst into tears because I see myself in them,” another said.

In recent years, the plight of “left-behind children” has attracted growing attention. Chinese experts warn of psychological and emotional problems among kids raised apart from their parents. Such children often do worse at school than their peers. Studies have suggested that they develop increased tendencies toward suicide and alcohol abuse.

But in cities, migrant children face problems as well; they are often barred from public schools and medical care unless their ­parents have residency permits. And city folk often discriminate against the rural families, regarding them as crass and uneducated.

“The countryside has been good for Beibei,” her grandmother Yang Peiyun, 51, said on a recent day in their village. “The food here is clean. The air is not polluted like in the city.”

But, she added, “there is no future for her in the village. There is nothing here but mountains.”

Several weeks ago, as winter approached, the couple asked Beibei’s grandmother to take her to the city for a visit.

As the little girl walked up the apartment stairs, holding her father’s hand, she frowned and asked, “Whose home is this?”

“This is Beibei’s home,” her parents told her, but she shook her head.

That night, when Wang tried to lie down with her, Beibei objected.

Running to her grandmother, she cried out: “I don’t want Mom.”

Recalling those words the next day, Wang wiped away tears as she stood outside their barbershop.

“I want so much to teach her the real meaning of a mother,” she said. “A mother is the one who gives birth to you. She is the one who teaches you to walk and talk and sing. A mother watches as you grow up. She is the person closest to you.”

Wang and Wu have since started planning to bring their daughter to the city permanently. They haven’t figured out how to overcome the financial hurdles, but they have set a deadline: the beginning of February, after the Chinese New Year.

“We missed so many things already, like her first step and first words,” Wang said. “But she’s still young. It’s not too late for her to learn what it really means to have a mother.”

Li Qi contributed to this report.