This trend was started by a book initially published in 2017, Banxiaoshi Manhua Zhongguoshi (A Comic Book About Chinese History That Can be Finished in Half an Hour).

Its author Chen Lei, whose pen named is Erhunzi, says he did not become interested in history until he was 20, after playing a computer game about World War II while studying mechanical science at university.

"At that time I knew nothing about the people, places and historical background in the game, so I started reading books about WWII and found that I had to first read about WWI to understand WWII," he said at a book event last year.

He said that gradually, his previously sparse historical knowledge developed into clear narrative lines, and he found that the essence of history is stories.

While working as an automotive designer in Shanghai, Chen began creating comic strips full of jokes and vivid metaphors based on historical facts.

For example, when talking about the seven powers during the Warring States Period (475-221 BC), he compared them to seven students in a class. One student named Qin was so outstanding that he looked down upon all the others, so the other six united to fight him. The strategy was known historically as hezong, but Qin managed to sow discord among the allies and break up the union.

In 2014, Chen started posting his comics on his WeChat account, and by 2018 he had 5 million followers.

"We (the publishing team) spent 80 percent of our time processing historical knowledge so as to represent it in a straightforward and clear way that long-form text can't achieve, so that readers can quickly understand people's relationships and other information," he said.

Choosing only core events from critical historical periods, Chen tried to create an interesting narrative form for readers to easily understand and remember events in Chinese history.

After finishing his part, Chen would invite experts to review his work to make sure there were no mistakes pertaining to historical facts.

In April 2017, when the book was published by Dookbook, it set a record of selling out within seven hours on online shopping platforms.

To date, the Half-An-Hour Comics series includes 47 books. The latest is about Chinese geography, says Shen Jun, who is in charge of the series at Dookbook.

Selling more than 20 million copies to date, the series mainly consists of four themes — history, literature, Chinese ancient civilization and science.

"Actually, at first, Erhunzi created the comic strips for adult readers, but later we found his work is most popular among primary school students because kids need to study Chinese history, but what teachers teach at school is not so easy or interesting enough for them to understand," Shen says.

"In comparison, readers need only a little time to read our comics but can gain a lot of knowledge, which is how we positioned the books in planning.

"Just like the educational idea of 'learning through play', through the metaphors, jokes and images in the comic books, readers can easily master otherwise boring knowledge."