Keizō Obuchi
He was a member of the "YKK" faction with Kōichi Katō and Jun'ichirō Koizumi, and also led a small faction that bore his name. He sought to oust the incumbent prime minister Keizō Obuchi in the LDP presidential election of 1999, but placed third among three candidates (Obuchi 350, Katō 113, Yamasaki 51). Obuchi attributed his victory to the support of Yoshirō Mori, who succeeded Obuchi as Prime Minister following Obuchi's stroke and coma in early 2000. In November 2000, along with Katō, Yamasaki was heavily involved in a failed no confidence motion against Prime Minister Mori.