Photo/Illutration Yukio Edano, left, head of the Constitutional Democratic Party, and Kenta Izumi, chief of the Democratic Party for the People's Policy Research Council, after a joint news conference on Sept. 7 (Hiroki Endo)

The official campaign kicked off Sept. 7 to elect the leader of a new political force that merges the two largest opposition parties and hopes to finally end the dominance of the ruling party.

Entering the fray are Yukio Edano, who heads the main opposition Constitutional Democratic Party of Japan (CDP), and Kenta Izumi, chief of the Policy Research Council of the Democratic Party for the People (DPP).

The election will be held on Sept. 10.

The new party will comprise 149 lawmakers from both houses of the Diet: 88 CDP members, 40 DPP members and 21 independents.

But Yuichiro Tamaki, head of the DPP, and several other party members will not join, a setback because the new force needs to gather as many members as possible to counter the overwhelming strength of the Liberal Democratic Party in the Diet.

The LDP will hold its own presidential election on Sept. 14, with the winner assured of being named prime minister to replace Shinzo Abe.

Edano, 56, seen as the front-runner in the opposition party race, is endorsed by senior CDP legislators, political veteran Ichiro Ozawa of the DPP, and two heavyweight independents, Katsuya Okada, a former foreign minister, Yoshihiko Noda, a former prime minister.

“I entered the race to offer an alternative to (the LDP administration) and regain a tense atmosphere in the political world,” Edano told reporters. “We should face the reality in which the public is in.”

Izumi, who is backed by Hirofumi Hirano, secretary-general of the DPP, told reporters he will work “to create a main opposition force that can offer many policy proposals and will be trusted.”

He also called for transparency and a democratic process in the management of the new party, alluding to criticism against Edano’s management style.

The election carries weight because the winner will likely lead the new party in the Lower House election expected by next autumn.

Members will also vote for the name of the new party. Edano is pushing for the CDP, while Izumi backs Minshuto (Democratic party).