China heavily censors any material that may not be compliant with its policies or is deemed potentially divisive or critical of its policies or leaders.

The book "Chongzhen: The Diligent Emperor of a Fallen Dynasty" was recalled on Oct. 16, due to "printing problems", its publisher, Dook Media Group, said in an online notice.

Reuters could not immediately verify the notice, and the publisher did not immediately respond to a request for comment.

Censors have also scrubbed all screenshots of comments circulating online that likened the emperor to Xi, who began this year a precedent-breaking third term as president.

Chongzhen, whose reign ended with his suicide in 1644, was noted by historians for his diligence as much as his paranoia, including the constant questioning of his subjects' loyalty.

The censorship was likely because of online parallels drawn between the ailing Chongzhen's rule and perceived governance mistakes by Xi, from last year's strict zero-COVID lockdowns and protests to the current economic slowdown, said Srikanth Kondapalli, a professor of Chinese studies at Jawaharlal Nehru University in New Delhi.

"Using historical allusion and double entendre has become a way for the Chinese to work around strict censorship," he said.

Several Chinese readers shared images of the book cover on their Weibo social media accounts, including words in bold critical of the emperor such as, "Bad moves one after another, the more diligent (Chongzhen was), the more the kingdom died".

The shared images also included the book's cover, which showed Chongzhen's name overlaid with a red noose. One other blurb on the cover read: "paranoid and mercurial".

The book is currently not available online. Searches for the title on Weibo yielded no results. The name of the author, Chen Wutong, who died this year, was also censored on Weibo.

Published on Sept. 1, the book was a reprint of a 2016 text that had a different cover and title.

In a recently released biography of the world's richest man, Elon Musk, by Walter Isaacson, phrases such as "This is fascism", which could be perceived as critical of China's recent zero COVID policies championed by Xi, were obscured in white.

In the past, pictures of Winnie the Pooh, an internet meme that played on Xi's supposed likeness to the rotund cartoon bear, have also been scrubbed from the Chinese internet.

(Reporting by Ryan Woo and Beijing newsroom; additional reporting by Eduardo Baptista and Brenda Goh; editing by Miral Fahmy)