Family ties are hugely important in China, but thousands of Chinese parents are still sending children as young as three away to boarding school. Why do they do it?

Kelly Jiang bounces into her kindergarten classroom, her parents a few steps behind.

"Bye Mum and Dad," the four-year-old trills, with barely a backwards glance.

As her parents wave farewell, she's already happily chatting to her teacher and her classmates.

There are no tears, no cuddles and no long goodbyes, which is all the more remarkable, because Kelly won't see or talk to her mother and father for another four days.

Kelly is one of dozens of three and four-year-olds sent to this boarding kindergarten in Shanghai. From Monday morning to Friday afternoon she and her classmates play, learn, eat and sleep in their brightly coloured classroom and its attached dormitory, only going home at weekends.

Image caption The children on the way to have a shower

They are not alone. There are other boarding kindergartens in Shanghai, Beijing and other major Chinese cities. While no official figures are available, it's estimated that the number of boarding toddlers runs into thousands nationwide.

We let go of her earlier to help her become more independent and be able to survive in society Jamie Jiang, Parent of four-year-old Kelly

In traditional Chinese culture, family is prized above all else - so how can the phenomenon of the boarding toddler be explained?

There are a few reasons, says Xu Jing, executive principal of the Kangqiao kindergarten affiliated to the China Welfare Institute (CWI) in Shanghai.

"Some think it's good for the children because it helps promote independence. Other parents don't have time or energy to look after their kids," says Xu.

"Also, in traditional Chinese culture many grandparents live with the family, and [because of China's one child policy] sometimes there are four grandparents, two parents and just one child in a home.

"Some parents worry that the grandparents will spoil the child, so they send them here."

Image caption Kelly's parents say they cherish the time they have with her

Kelly Jiang's father, Jamie, is an investment consultant, and her mother doesn't work. As part of China's wealthy business elite, they are able to afford the monthly fees of $1,000 (£622).

It achieves independence only in parents' minds - it is brutal Han Mei Ling , Psychologist

"We did a lot of research, and discovered that boarding kindergarten benefits outgoing children. It helps them become more independent, and have better life skills," explains Jiang.

"Our Kelly was a very cheerful baby who liked her own space, so we sent her for a trial. Then we asked her if she wanted to stay in the boarding class, and she said yes."

Jiang's eyes fill with tears when asked if he misses his bubbly little girl.

"At first we missed her so much. But we think that as the world is more global, sooner or later she will leave us.

"We let go of her earlier to help her become more independent and be able to survive in society. But we cherish the time we spend with her."

Image caption Parents come to pick up their children on Fridays

Boarding kindergartens were established in China in 1949 to look after war orphans of the civil war, as well as the children of new Communist Party leaders who suddenly found themselves too busy for childcare.

Find out more Image caption Interviewees with children of their own warmed to Scarlett - and she to them Madeleine Morris visited Fiji and China to investigate different approaches to childcare

Part one of her documentary Who's Left Holding The Baby? was broadcast on BBC World Service on 29 October - part two on 5 November Catch up via BBC iPlayer Radio

These days, as the queues of Audi and Mercedes cars at drop-off time attest, it is a very different crowd who send their children to boarding kindergartens.

Numbers peaked in the 1990s, when sending a young child to such schools was a fashionable status symbol.

But recently the system has become less popular. Some boarding kindergartens, both private and state-run, are closing. Others are switching from boarding classes to day care.

The CWI kindergarten in Shanghai used to be exclusively boarding, but now only three out of 22 classes for young children are residential.

"Chinese parents are now starting to realise that it's important to spend more time with their kids when they are very young, because they are learning and it's a very important stage of growth," says Xu Jing.

"We also advise parents that if they have the time and ability to be with their children, day care is a better option."

Psychologist Han Mei Ling is a vocal critic of boarding kindergartens, having treated a number of adults and teenagers scarred by the experience.

More from the Magazine "Our sojourns in Fiji and China were without doubt the most inefficient work trips I have ever undertaken. Instead of scheduling five interviews in a day I could manage just two, with nap time, playtime and mealtimes taking precedence. But being forced to slow down also helped me to look closer, think longer and listen harder, simply because I had time to. " Read more on working with a toddler in tow

"They feel abandoned and irrelevant. They struggle to find their place in life, and they don't know how to behave in their own family," she says.

"It achieves independence only in parents' minds - it is brutal."

Han believes a culture where family pride depends overwhelmingly on a child's success or failure is the reason some parents still send their children to kindergartens.

"Most Chinese families understand that it's important for children to be with their parents, but they also have very high expectations of their kids," she says.

The experience of boarding is seen by some parents as a way for a toddler to get ahead. From boarding kindergarten, they are likely to go on to a boarding school and then, the hope is, they will win a place at a good university.

But a number of former boarding kindergarten pupils told me it had been a bad experience.

Fashion model Wang Danwei was sent to board aged three after her parents divorced.

"In the end I accepted it in a passive way, but I never liked it," she says. "When I later went on to boarding school I felt a deep sense of exclusion, and spent most of my time alone, keeping quiet and resisting getting to know new people."

Image caption The children have a wide range of toys to play with

Adjusting to life away from their parents is difficult for nearly all toddlers. During the day, the children are busy with fun activities, but when I made a bedtime visit to the three-year-old boarders at the CWI's Kangqiao campus, about half the class was in tears.

Children cried out for their parents in heartbreaking scenes of distress, as teachers tried to comfort them.

"We are seeing a lot of tears tonight because it is the start of the academic year, and these children are new to boarding," kindergarten administrator Huang Ying assured us.

"In about two months no child will cry at bedtime. The kids also have family photos, so when they need their parents they can talk to the photos and it's just like they are there with them."

Mo Li, a 17-year-old student, said she, too, found it difficult at first as a three-year-old boarder, but then had a positive experience.

"At the beginning I missed home, but the food was very good, and the environment lovely, with lots of trees," she says.

"I think that now, compared to other people my age, I am more independent and more responsible. And you may see this as a positive or a negative, but I also cherish my relationship with my parents more than my peers do."

Madeleine Morris visited Fiji and China to investigate different approaches to childcare. Part one of her documentary Who's Left Holding The Baby? was broadcast on BBC World Service on 29 October - part two on 5 November

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