Hergé's early Tintin albums were highly dependant on stereotypes for 'comedic' effect. Russians (Bolshewiks) and Americans were portrayed as evil, black Africans as lazy and dumb.
At the close of the news paper run of Cigars of the Pharaoh, Hergé had mentioned that Tintin's next adventure (The Blue Lotus) would bring him to China. Father Gosset, the chaplain to the Chinese students at the University of Louvain, wrote to Hergé urging him to be sensitive about what he wrote about China. Hergé agreed, and in the spring of 1934 Gosset introduced him to Chang Chong-chen, then a young sculpture student at the Brussels Académie des Beaux-Arts. The two young artists quickly became close friends, and Chang introduced Hergé to Chinese history, culture, and the techniques of Chinese art. As a result of this experience, Hergé would strive in The Blue Lotus, and in subsequent Tintin adventures, to be meticulously accurate in depicting the places which Tintin visited.
As a token of appreciation, he added a fictional "Chang" to The Blue Lotus, a young Chinese boy who meets and befriends Tintin. Hergé mocks his own naïveté deep inside the album, when he tries to let Tintin explain to the fictional Chang that Chang's fear for the 'white devils' is based on prejudice. He then recites a few Western stereotypes of the Chinese. This Chang will later return in Tintin in Tibet.
As another result of his friendship with Chang, Hergé became increasingly aware of the problems of colonialism, in particular the Japanese Empire's advances into China. The Blue Lotus carries a bold anti-imperialist message, contrary to the prevailing view in the West, which was sympathetic to Japan and the colonial enterprise. As a result, it drew sharp criticism from various parties, including a protest by Japanese diplomats to the Belgian Foreign Ministry. However, the passage of time has since vindicated Hergé's views.
At the end of his studies in Brussels, Chang returned home to China, and Hergé lost contact with him during the invasion of China by Japan and the subsequent civil war. More than four decades would pass before the two friends would meet again.
In a remarkable instance of life mirroring art, Hergé managed to resume contact with his old friend Chang Chong-chen, years after Tintin rescued the fictional Chang in the closing pages of Tintin in Tibet. Chang had been reduced to a street sweeper by the Cultural Revolution, before becoming the head of the Fine Arts Academy in Shanghai during the 1970s. He returned to Europe for a reunion with Hergé in 1981, and he would settle in Paris in 1985, where he died in 1998.