Abstract
Based on the Basic Law on Reform of the National Public Service System 2008, the National Public Service Act was amended in 2014. The series of reforms includes measures to increase diversity and openness in the public service system, such as open competition recruitment and personnel exchanges between the public and private sectors. This paper focuses on senior public servants, who are key actors in the policy process, and analyzes the recent senior executive service system and the relationship between politicians and bureaucrats from the point of view of contestability. The reforms have made senior executive services more responsive to politicians, but on the other hand, the traditional Japanese personnel system (seniority-based by ministry, types of recruitment examination, and year of employment) has been maintained. Compared to major developed countries, Japan's public service system is extremely closed, and public-private exchanges and open recruitment have not increased diversity and mobility in the public service system.