Reconsidering the Passage of the 1925 Peace Preservation Law at its Centennial

Abstract Based on excerpts from the author’s book, Thought Crime: Ideology and State Power in Interwar Japan (Duke University Press, 2019), this article explores the passage and early implementation of Japan’s infamous prewar law, the Peace Preservation Law (Chianijihō). Enacted in March 1925, this law was utilized to arrest over 70,000 people in the Japanese metropole and tens of thousands more in Japan’s colonial territories until being repealed by order of Allied Occupation authorities in October 1945. Proponents initially explained that the law was to suppress communists and anticolonial activists for threatening the national polity, although how to exactly define such threats remained ambiguous. By the 1930s the purview of the law expanded and was used to detain academics, other activists, and members of religious groups who were seen as challenging imperial orthodoxy. This article focuses on the interpretive debates over the law’s central category— kokutai , or national polity—and how its interpretation started to transform as the law was first applied in the late 1920s and early 1930s. The occasion of the Peace Preservation Law’s centennial invites us to consider its history and legacy, especially as policing and state power have expanded since the so-called war on terror.