In 1946, a British military court in Singapore tried a Korean national named Cho Un-kuk for war crimes against Allied prisoners of war on the Thailand-Burma Railway during the Second World War. The evidence against Cho was scanty, but he had been part of a group of Korean guards notorious for brutality towards prisoners. In expedited proceedings relying heavily on affidavit material, Cho was found guilty and sentenced to fifteen years in prison. The trial revealed both Cho's unexpected transnational background as a dentist in pre-war British India and the complex position of Korean guards on the Railway. Often characterized as universally brutal as a result of their own ill-treatment by the Japanese colonial system, the guards responded in many different ways to the pressures and opportunities of service subordinate to the Japanese military. After sentencing, Cho served time in Singapore and Japan. He left prison a broken man in 1955. Like other Koreans who had been in Japanese military employment, he was spurned by other Koreans as a collaborator. Only in 2006, after his death, was he officially recognized as an unwilling conscript into Japanese service. His case illustrates the difficulty of distinguishing victims and perpetrators in the tangled circumstances of the Second World War.