Educational books and test preparation books accounted for nearly 40 percent of book sales on Tmall, while the most popular books among those aged between 30 and 40 were parenting and educational books for children. Those in their 20s mostly bought books on English and administrative tests, while teenagers favored guide books for college English exams and young adult fiction.

Zhang Wei, manager of the book department at Tmall, says part of the online sales growth came from purchases made in remote rural areas, such as certain parts of the Tibet and Xinjiang Uygur autonomous regions, thanks to publishing houses opening special postal delivery services for students there.

Liu Yu, manager of the children's book department at another big Chinese online store, Dangdang, says the company sold 620 million children's books in 2018, which accounted for 25.9 percent of the whole book section's total sales.

Sun Lijun, a professor at Renmin University of China who specializes in publishing, says educational books and textbooks have long been the largest proportion of published books in China, which is something that many publishers have wanted to change for some time.

"The country's strength in publishing should be reflected in a flourishing and diverse book market," Sun says. "But right now, Chinese people are still more interested in textbooks and exam guides because they see reading as a utilitarian act.

"People want to see a direct benefit from reading a book," he adds. "That is the mentality which has resulted in the popularity of test preps and other educational and self-help books."

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