Young people gather at LA CASA, a Beijing-based creative artist studio, to participate in a party with the theme Secret Garden. [Photo by Yu Zhuo/For China Daily]

Secret Garden sold more copies than any other book in the whole year, according to 2015 list released by Amazon China on Dec 10.

The book proved to a black horse with no slowdown in sales on Amazon.cn since its publication on June 1.

Shi Jianjun, vice-president of Amazon China, noted that Secret Garden transformed a traditional book into a coloring book, adding that social media also contributed to its success. Shi said the trend showed that TV and films based on books helped to promote reading. For example, the sales of The Common World by Chinese writer Lu Yao, and Wolf Totem by another Chinese writer Jiang Rong were given a boost by the popularity of their TV and film adaptations.

And the adaptations can also stimulate the sales of related books. Comparing the sales of the books before and after the release of their TV and film adaptations, The Common World grew at six times, The Journey of Flower 10 times and Nirvana in Fire 33 times.

One week after its TV adaptation's launch on Nov 30, the sales of the book The Legend of Miyue that was published in August rose by 1.5 times.

Jinan, Ningbo, Chongqing, Zhengzhou, Changsha, Foshan, and Hangzhou rounded up the top 10. And each city has its own taste of books. Books about economy and management are popular in Suzhou, while the ones focusing on children's education are hot in Hefei. And English study and examination books are popular in Jinan.