Following the October Revolution, tens of thousands of White Russians sought refuge in China and became inevitably involved in the escalating Sino-Japanese War (1931–1945). The Japanese deployed measures of coercion, material incentives, and ideological indoctrination to recruit White Russians for Japan’s military and political maneuvers in the China theater of WWII. With the conclusion of the war, the Chinese Nationalist government launched a legal campaign against all collaborators with Japan and labeled them hanjian, “traitors to the Han Chinese,” regardless of the race and nationality of the defendants. Based on archival materials in Chinese, English, Japanese, and Russian, this article examines the context and process of the incrimination of White Russians in China’s postwar trials of traitors. With no consular support and little diplomatic significance, the White Russians became the ideal foreigners for the Chinese government to exercise its newly recovered judicial sovereignty and to claim its legitimacy in administering justice related to war crimes. Dozens of White Russians were convicted of the crime of hanjian and sentenced to prison terms of varied lengths.