This chapter presents a case study of Japan’s ICT regulation after the 1980s. It first reviews the development of Japan’s ICT sector, starting from telecommunications liberalisation in 1985. This review is followed by an exploration of power relations between key actors including those within the core executive. Paying attention to how power relations have changed among core executive actors, the third section explores how the core executive in the ICT sector has transformed its internal power relations by exploring key actors – Cabinet ministers, party politicians outside the Cabinet and civil servants – and structures within the core executive. Two core issues emerge in the analysis: first, the relationship between Cabinet ministers and party politicians outside the Cabinet including those in the ruling party; and secondly, the partisan confrontation between the Liberal Democratic Party (LDP) and the Democratic Party of Japan (DPJ).