ZHANG Yichao wants his children to sing and to sing out loud about good and happy things. His charges, from primary school students to high school teenagers, are all children of migrant workers who have a hard life in Shanghai.

Some parents drive illegal taxis near Metro stations, always afraid of being caught by police. Some wash dishes in restaurants until midnight and have no time to look after their children. Some work on construction sites, sometimes getting injured. Some put up shabby street stalls, selling pirated CDs.

It would seem these children don't have a lot of good things to sing about.

Zhang, a 34-year-old Shanghai native, has been singing with these children for the past 10 years and says he will sing for the rest of his life.

"Mr Zhang, can I use the computer and play games now?" asks 10-year-old Wu Zeyu with a grin.

Zhang asks the boy from Xuzhou, Jiangsu Province, if he has finished his homework. "No work, no play," he says firmly, but then he gives a fatherly smile.

The boy makes a grimace and rushes downstairs to join classmates who are reading quietly.

Zhang's Jiuqian Classroom is a nonprofit educational institution that provides quality free private tutoring and extracurricular activities for around 80 children of migrants. It has two centers, one in Pudong's Chuansha area and one in Yangpu District's Wujiaochang area.

Ten years ago, Zhang was a philosophy student in Fudan University and he discovered the world of migrants while he was out looking for mulberry leaves to feed his silkworms. He came upon nearby Jiangwan Town and a school for migrants' children.

"There were dim classrooms, peeling paint, rotten wooden desks and chairs," he recalls. Zhang started a team of volunteers from university to teach the children how to sing. After graduation, the volunteers went their separate ways.

Zhang didn't give up. He continued to visit the children and sing with them after school.

He then got a job at an international school.

"I came to see the distinct gap between my rich students at international school and those in poverty. That's the real world," he says.

In 2008, Zhang registered the Jiuqian Classroom as a nonprofit organization in the Pudong New Area and got support from the district's Civil Affairs Bureau.

Little by little, his efforts to help migrants' children have borne fruit.

Today Jiuqian has been a place visited almost daily after school by migrant children living or studying nearby. They play, have classes, do their homework, or just chat with Zhang and other volunteers.

Fifth-grader Yang Hong, living just across the street, stops by every day for reading, singing and playing cards with his playmates, doing his homework or taking a fun class.

"We have all kinds of interesting lessons here and the teachers are just like big brothers and sisters, who help me with my schoolwork," he says. Little Yang loves reading about animals and holds up the book "Animal World" that he has read three times.

The classes are varied and interesting: choral singing, piano, erhu (two-string Chinese fiddle), guitar, clay sculpture, painting, cooking, computer skills and English. They are taught by volunteers, who are university students, professional workers and professionals.

Teenage boys and girls learn about physical health and mental health.

A core of 30 volunteers teaches after school and on weekends. They give lectures and one-on-one tutoring.

"We are quite strict with volunteer teachers. It's not a one-time thing because it takes time for a teacher to build up trust with the children," Zhang says. Each volunteer has to hand in a detailed teaching plan and he or she is required to teach for at least half a year.

Jiang Xudong, a post-graduate from Tongji University's Law School, is a new volunteer, teaching sculpture every Friday afternoon.

"To share the sculpture fun I learned from my parents and do something for migrant children are two things I want to do before I graduate," says Jiang. "It's just a 10-minute bike ride from my school," he says. "The kids love me."

The Puxi classroom in the Wujiaochang area is a two-story apartment, fully furnished in bright colors and equipped with an open kitchen and a spacious living room for activities on the first floor. The second floor contains a computer room and large balcony.

"There are rules the children must obey. We take this seriously," says Zhang. Each child can sign up for courses that interest them, but they must attend; if they are absent, they must present a note from their parents.

Students take turns to be on duty and do chores. Empty water bottles must be placed in the trash cans; wet umbrellas must be placed on shelves in the doorway; food and drink are only allowed in the kitchen; no playing with the buttons on the building's elevator.

Most of the migrant families live in the dilapidated houses that are about to be torn down.

"I once met a girl near the center and she was squeezed into a garage with her brother and parents - it was no more than 10 square meters," says Gao Tianxiang, a staff worker at the center. "I asked if she wanted to come play with us. She was timid, but nodded and said 'thank you'."

Many migrant's children are shy and introverted, sometimes hostile. A 14-year-old girl from Jiangxi Province is very thin and tiny, only around 140 centimeters tall. "Her parents fight every day and she once told me that she never wanted to get married," says Gao.

Two years ago when the girl went to Jiuqian, she was silent and always kept to herself, but now she raises her hand to ask questions in class and jokes with classmates. "She smiles a lot now. It's a change for the better," says Gao.

Founder Zhang has big ambitions. He wants to build Jiuqian into an integrated educational institution for migrants' children, offering career planning, life guidance and even the opportunities for overseas study.

"I want them to see more of this world, the good side and the bad one," says Zhang.

"What they need is an opportunity."