Official campaigning began Thursday for the Upper House by-election in Saitama Prefecture, where a former governor is pitted against the head of a minor opposition party critical of public broadcaster NHK.

Independent Kiyoshi Ueda, 71, is an established figure after serving as Saitama governor for 16 years, while Takashi Tachibana, 52, leader of NHK Kara Kokumin o Mamoru To (the Party to Protect the People from NHK), is known for making controversial remarks — most recently a suggestion that genocide is the solution to overpopulation.

Ueda was a member of the now-defunct Democratic Party of Japan, and served four four-year terms as Saitama governor from 2003.