With Bing, Microsoft tried to play by China’s rules. For example, a search for the Dalai Lama, the religious leader, would turn up state media accounts within China that accused him of stirring up hatred and separatism. Outside the country, it would point to sites like Wikipedia.

Other searches, like for Tiananmen Square or the Falun Gong religious group, were similarly scrubbed, though over the years users reported that using coded language could help turn up posts about some topics that were generally controlled.

Blocking Bing would brick over one of the last holes in a wall of online filters that has isolated China’s internet from the rest of the world. Although not widely used in China, Bing has remained an option of last resort for some in China looking for an alternative to the dominant local search engine, Baidu. While it continues to dominate search traffic in China, Baidu has been at the center of complaints about poor search results and advertisements for questionable medical treatments.

Earlier this week, a former journalist, Fang Kecheng, accused Baidu of largely returning search results that were links to its own products instead of those from external sites. The accusation, which Mr. Fang posted on social media with the headline “Baidu the Search Engine is Dead,” went viral in China.

Baidu said in a statement that less than 10 percent of its search results included one specific Baidu product that Mr. Fang had singled out, and that its practices of using its own products in search results helped speed up download times.

In an interview, Mr. Fang said the Chinese internet was developing into a series of walled gardens, rather than the sprawling forum for ideas that makes online life appealing to many, thanks to censorship and to the rise of big Chinese internet companies like Tencent and Bytedance that dominate the online experience on mobile phones. Blocking Bing would only make it worse.

“Bing compromised in order to have a Chinese version to get into the country,” said Mr. Fang, a doctoral candidate at the Annenberg School for Communication at University of Pennsylvania. “It would be pathetic if even this can’t exist. We have one less alternative.”