Abstract
Although the House of Councillors elections, at a number of critical times, have played important roles in shaping post-war Japanese politics, the existing studies of electoral politics in Japan have focused predominantly on the House of Representatives elections. Rigorous empirical analysis of the House of Councillors elections has been limited (except for the studies using post-election surveys), and, for this reason, we do not yet have full understandings of the dynamics of postwar political competition and resultant policy processes in Japan. We argue that one of the major reasons for the lack of studies on Japan's House of Councillors elections is simply the lack of systematic database of these elections. Accordingly, we have compiled detailed municipality-level election results of most House of Councillors elections held during the post-war period and developed a user-friendly database available online. We hope that this new database will facilitate further studies on Japan's bicameralism and the roles of the House of Councillors elections in political and policy processes in Japan, and will motivate comparative scholars worldwide to use Japan as a case to develop and refine theories of electoral politics. This article introduces our new database and explains how to use it.
