The incumbents in Wakayama and Yamaguchi will each go up against an independent in the Aug. 8 gubernatorial elections, with all four registering Thursday.
The elections will be held after the incumbent governors' terms expire.
Wakayama Gov. Yoshiki Kimura, 52, seeking his second four-year term, has the support of the Liberal Democratic Party, New Komeito, the Democratic Party of Japan and the Social Democratic Party, as well as about 700 businesses and labor organizations in the prefecture.
Toshitaka Izumi, 66, backed by the Japanese Communist Party, will challenge Kimura in the election.
Yamaguchi Gov. Sekinari Nii, 61, eyeing a third term, is up against Toshiki Fukue, 63, an independent backed by the JCP.
Nii has support from the LDP, DPJ and New Komeito, as well as some 50 business and labor organizations in the prefecture.
Fukue, a former chairman of the prefectural labor federation, has criticized Nii for creating a financial catastrophe for the local government.