In a tale taught to generations of Chinese schoolchildren and celebrated in film, theater and paintings, five Communist soldiers who had fought off the Japanese invaders in World War II, killing dozens, chose to leap off Langya Mountain, shouting “Long live the Chinese Communist Party!” rather than surrender.

But Hong Zhenkuai, a historian, challenged the story of the “five heroes of Langya Mountain.” In two articles published in 2013, he questioned how many Japanese soldiers were actually killed and whether the five men — three died but two survived the fall — had slipped rather than jumped off the cliff.

In June, a Beijing court ruled that Mr. Hong, a former executive editor of the history journal Yanhuang Chunqiu, had defamed the heroes and ordered him to post a public apology on websites and in news outlets. He appealed, and on Monday, the Beijing Second Intermediate People’s Court, in a final decision, upheld the ruling against him.

“I certainly will not apologize,” Mr. Hong said in an interview on Monday. “This is basic academic freedom, and I need to maintain my dignity as an intellectual.”

Mr. Hong, who called the trial “political,” has said that he was trying to determine the truth through careful research and that the plaintiffs, sons of two of the “five heroes” who filed the suit last August, had not provided any evidence that disproved his findings. ...