FIVE HEROES VILLAGE, China—A jagged cluster of granite spires where one of China’s most celebrated war skirmishes unfolded has once again become the backdrop to a battle, this time over the right to question the Communist Party’s version of history.

In June, a Beijing court declared writer Hong Zhenkuai guilty of libel for challenging elements of the “Five Heroes of Langya Mountain,” a tale of patriotism and self-sacrifice taught to generations of Chinese school children. In raising doubts about the tale, the court said,...