His school uses the British Associated Board Royale School of Music grading system.

"It examines not only the playing skills but also their understanding and perception of music," he says.

But some discipline is required for any music student, no matter how they're taught or graded.

Rindermann's students replace repetition with analyses of the melodies and rhythms to help students "collect the beat". If they can sing it, they can play it, he believes.

The 43-year-old became interested in music at age 5, when he received a toy marimba. He started a decade of piano lessons under an Indonesian teacher in Berlin the following year.

"My teacher didn't speak much German, but language was never a problem," he says. "Music is universal."

He studied economics in university but maintained his musical interests through his 2007 arrival in China.

"I would go up and play whenever I saw a piano," he says.

Rindermann played jazz piano in a Suzhou bar and won first prize in the 2011 Suzhou talent show for expatriates with a jazz adaptation of a Chinese pop song and a piano solo.

He's happy to be able to live his dream of working with music. Raffles Music Class charges 4,200 yuan ($687) a year. It's sustainable but not highly profitable, Rindermann says.

But he hopes to grow.

"I wish to expand the school to more cities of China, maybe Shanghai," he says.

"I also want to organize music tours for Chinese families to Germany to participate in all the music festivals there. I hope to bring the joy of music to more people in China."