"In the beginning, the music sounds very simple, just like the lines of the calligraphy. Then the music develops and grows on its own, like the movements of Han's strokes," says Yao, adding that the music piece also shows his respect for Han.

Born in Jinan, Shandong province, Han recalls that he was intrigued by ancient Chinese characters when he was a child. In his eyes, all those mysterious characters are beautiful with shapes full of imagination.

"Ancient Chinese characters are an important part of Chinese culture and history. With thousands of years of development, Chinese characters have gone through changes and reforms. I love ancient Chinese characters, which represent objects or ideas through simple drawings. Some characters remain mysterious to us because even experts cannot interpret their meanings," says Han.

When Han started writing, the series didn't even have a name. Tian Shu was suggested by historian Ji Xianlin (1911-2009). Now, Han is working on the fifth and sixth Tian Shu books.