Hayato Ikeda
Kosaka first became a member of the House of Representatives in 1946, being a representative for the Nagano Prefecture. He served at the lower house 16 times and held different ministerial post. On 6 September 1960, Kosaka visited Seoul, being the first Japanese official to visit South Korea since 1945. He was appointed labor minister in the Yoshida Cabinet, foreign minister in the cabinets of Hayato Ikeda and Takeo Miki.