Sun Yu was a major leftist film director active in the 1930s in Shanghai. One of the core directors of the Lianhua Film Company, Sun Yu made a name for himself with a series of socially conscious dramas in the early to mid-1930s. After the Japanese invasion of China in 1937, Sun Yu made his way to the interior, where he continued to make films glorifying the war effort against the Japanese.
His career took a turn for the worse after the Communist victory in 1949. In The Life of Wu Xun, Sun Yu's big-budget biographical picture of the titular Qing Dynasty educator, Sun attracted the wrath of Mao Zedong, who personally criticized the film in an essay. Though Sun never fully recovered from the episode, he has regained his reputation as one of the foremost filmmakers the golden age of Chinese cinema.