日本新党
After serving two terms in the National Diet, he left in 1983 to become the governor of Kumamoto, where he served until 1991. During his term as governor, he complained about the powerful bureaucracy of the central government. Hosokawa pursued an aggressive economic policy and strengthened environmental laws. In May 1992, an ongoing campaign contribution scandal inspired him to form the reformist Japan New Party (JNP), which won four seats (one of which Hosokawa assumed) in the 1992 House of Councillors election.