From Danwei.org:

Yan Chongnian (阎崇年), a scholar specializing in Qing history and Manchu culture, was attacked on October 5 when he was in Wuxi to promote his new book, The Kangxi Emperor. The prolific author was smacked twice in the face, allegedly because the attacker disagreed with his historical views.

Yan is the director of the Manchu studies department at the Beijing Academy of Social Sciences and is a guest host on the CCTV-10 TV show Lecture Room. That program, which focuses on Chinese history and traditional culture, has made him a celebrity, as it has for other academics including Yu Dan, arguably the most popular exponent of Confucius ever.

Some statements which Yan’s online detractors contribute to the historian and call “traitorous”:

Wu Sangui, the general who has usually taken the blame for the collapse of the Ming Dynasty (the last Han Chinese Dynasty) by virtue of his surrender to the Manchu invaders, should be reevaluated for avoiding mass bloodshed that may have resulted had he not surrendered;

Censorship and crackdown on dissenting views by the Qing ensured social stability despite certain limitation;

The Manchu invasion promoted the integration of different ethnic groups, and the human loss it caused was inevitable.

According to the same article, the news broke first on the Tianya BBS (Chinese) before being picked up by mainstream Chinse media.

Jeremiah Jenne at The Granite Studio offers some insight into the high emotions surrounding just how to interpret the Qing and Manchu legacy in China:

The Qing can be a touchy subject. I’ve occasionally riled people by (tongue ever so slightly in cheek) correcting their assumption that I study Chinese history, telling them instead that ”I study the Qing Empire, of which China was one, albeit very large, part.”

The fact that the Qing Era was so prosperous and successful (for the first two hundred years or so) can be tempered in the zeitgeist by the knowledge that the Qing emperors were not Han, did not consider themselves Han, and would likely have chopped off anybody’s head who claimed that His Majesty’s Empire had succeeded due to Manchu assimilation, as early 20th-century Han nationalist historians argued in an attempt to reconicle past events with contemporary sentiment.

Prior to the 1911 revolution, revolutionaries such as Sun Yat-sen, Zhang Binglin, and Zou Rong wrote passionate tracts lamenting the depravity, cruelty, and, yes, the “Otherness” of the Manchu rulers. Post-1911, as the KMT and later the CCP took up the baton of statebuilding, the desire to hold on to the territorial conquests of the Manchus trumped ethnic nationalism, and the Manchus were brought into the fold of a newly-defined “Chinese nation,” which transcended Han ethnic or cultural definitions to include those groups, like the Tibetans, Uighurs, and Taiwanese, who had also been ruled by the Manchus. This is the narrative which dominates in the PRC today.

Danwei.org has also translated an interview with Yan which originally appeared in the Beijing Morning Post in Chinese. The interview adresses the quotes and views attributed to both Yan’s book and Yan himself which have been spreading rapidly on the Internet. Excerpts of the translation below:

BMP: Quotes circulating on the Internet, such as the “word prison” ensuring social stability and Han costumes having nothing to do with the national spirit, have caused lots of controversy. Did you say those things?
Yan: Let me make a statement here: I have checked up on all those quotes. I said none of them, they are pure fabrication. I has been critical of the “word prison” and never expressed any opinion about Han costumes. If someone insists that I said such things, please point out in which book and on which page, or in which one of my talks. The imprecision of the quotes is not scholarly at all.

[…]BMP: A poem on the Internet commemorating the 100th anniversary of the Qing emperor’s abdication claims to be your work and has been the target of criticism. There’s also talk that you lied when you said you were Han Chinese.
Yan: I can clear that up. I never write poems. I can show you my ID and tell you assuredly that I am a Han Chinese. I correct these Internet rumors every time someone asks. Someone even faked my blog and cooked up discussions between me and someone else. I can assure you that I do not blog.

[…]Those people, who probably haven’t read my books at all or watched all the episodes of my show, act out of nationalist prejudice to take things out of context and even distort and fabricate. Those who disagree with my historical views are entitled to do so. But hitting me is not about academics.