A Historical Study of the Adversarial System in Criminal Procedure and Its Implications for Criminal Justice Reform

The foundation of Korea’s modern criminal procedure system began with the adoption of Western legal traditions through the application of Japan’s old Criminal Procedure Code under the Chosun Criminal Order of 1912. This marked an indirect reception of the continental legal system via Japan. After Korea’s liberation, various elements of the Anglo-American legal tradition were introduced into our criminal procedure system during the process of enacting the Criminal Procedure Act. Following World War II, both Korea and Japan came under U.S. military administration, during which American criminal procedure and evidence law significantly influenced the development of legal systems in both countries. In particular, the enactment of Japan’s new Criminal Procedure Code in 1948 and Korea’s own Criminal Procedure Act reflected strong influences from Anglo-American law. Notably, adversarial principles—a hallmark of Anglo-American criminal procedure—were introduced during this period, along with key evidentiary rules such as the hearsay rule. The current Korean Criminal Procedure Act incorporates adversarial principles through provisions on the hearsay rule and cross-examination. Since then, through successive amendments to the law, systems aimed at realizing trial-centered and adversarial proceedings have been legislated. This paper examines the characteristics, origins, and issues of adversarialism under Anglo-American law, and explores the historical development of adversarial principles in Korean criminal procedure, particularly in relation to the hearsay rule. It also discusses the future direction of Korea’s criminal trials with respect to adversarialism. By developing a systematic understanding of adversarial principles originating in Anglo-American law, this study aims to deepen our understanding of the structure of Korean criminal procedure and ultimately explore more effective directions for a criminal justice system that ensures both procedural efficiency and the discovery of substantive truth.