YAMAGUCHI Natsuo

Yamaguchi served as a member of the House of Representatives from 1990 to 1996 and has been serving as a member of the House of Councillors since 2001. 

Yamaguchi served as the leader of the Komeito Party (公明党, Kōmeitō) from 2009 to 2024. In September 2024, he announced that he would not run in the party leadership election scheduled for the same month. Keiichi Ishii was elected as his successor unopposed. Following this, Yamaguchi took on the role of the party's Senior Advisor. In October 2024, after losing his seat in the House of Representatives general election, Ishii resigned, and Tetsuo Saito assumed the position of party leader.

As the party leader, Yamaguchi supported Komeito’s stance on constitutional revision, known as "kaken" (additive revision), as expressed in his 2019 speech (2019 speech). Komeito’s proposal of "kaken" involves adding necessary provisions to the existing constitution, rather than amending it, in order to address contemporary issues such as new human rights and the expansion of local autonomy, which were not anticipated at the time the current constitution was enacted.