One afternoon when Ma Xia was 6, he came home from kindergarten and told his mother that he wanted to learn to play the piano.

"We then sent him to have lessons. It was his own choice. His father and I don't know much about the piano or music, we just think it will be helpful to develop his intelligence and nurture his ability to appreciate music," says his mother, Xia Qin, 33.

The boy, now aged 8, has passed the grade examination and the teacher of the training course says he might even be able to pass the grade 4 exam, but his mother says the boy's hands are not big enough to master the musical works that the level-four test required.

"Some parents don't know how well their children can play. They often sign their children up for tests that they fail to pass," Qiu says.

The Central Conservatory of Music has more than 40 examination branches across the country. Each branch offers training courses and sells training materials.

Each year, thousands of children register for piano exams, with fees ranging from 50 yuan ($8) to 360 yuan.

The Central Conservatory of Music Press has recently published a new set of piano training materials titled Piano Squirrels for beginners.

"But the training institutions may not want to use our materials because unlike existing teaching materials, we combine the study of the musical instrument with the study of music theory, so that they may not be able to give separate lessons, which means less profit," Zhang said.