Photo/IllutrationYukio Edano, right, head of the opposition Constitutional Democratic Party of Japan, meets on Aug. 5 with Yuichiro Tamaki, who heads the Democratic Party for the People. (Takeshi Iwashita)

The head of the main opposition party is switching tactics and calling on smaller parties to form a larger and unified voting bloc in the Lower House to counter the dominance of the ruling coalition.

Party leader Yukio Edano explained the change in strategy Aug. 5 as offering the best chance of creating a political force strong enough to take on the ruling Liberal Democratic Party and its junior partner Komeito.

The Constitutional Democratic Party of Japan (CDP) had long argued that it would not be party to any move that simply created a larger bloc in terms of numbers without reaching agreement on key policy positions.

But on Aug. 5, Edano sat down with the heads of the Democratic Party for the People (DPP) and the Lower House group known as the Reviewing Group on Social Security Policy, and proposed that the three bodies unite to form a single voting bloc in the lower chamber.

Yuichiro Tamaki, the DPP head, welcomed the move that was in line with his repeated calls for opposition parties to close ranks and confront the LDP and Komeito in the Diet.

The CDP's about-turn in strategy suggests the party views enhanced cooperation with other entities as offering the best chance of snatching power when the next Lower House election is held.

The CDP won less than 20 seats in the July Upper House election and greatly reduced the number of votes it gained through the proportional representation constituency in comparison to the Lower House election two years ago.

In his meeting with Tamaki and Yoshihiko Noda, the head of the reviewing group, Edano said that one condition for forming the single voting bloc would be their full cooperation with the CDP's main policy initiatives of seeking zero dependence on nuclear energy and allowing married couples to use different surnames.

Edano asked for a response to his proposal by mid-August.

A single unified voting block would give the three groups 117 Lower House members compared with the 70 now held by the CDP.

"We will first of all move ahead with creating a larger bloc in the Lower House in order to heighten our ability to debate the ruling coalition," Edano said at a news conference after the meetings.

He said that both Tamaki and Noda gave positive responses to the proposal.

Edano also explained that he proposed a meeting with the Social Democratic Party on the same issue but did not receive positive feedback.

When asked by reporters about the party's new position rather than outright rejection of a merger of opposition parties, Edano said, "We have entered a phase that requires this form of taking on" the ruling coalition in the Diet.

He stopped short of saying if the voting bloc would be the first step to the three groups merging into a new political party.

Most of the members of the three entities were part of the Democratic Party of Japan before it disbanded after losing control of the government in 2012.

Later on Aug. 5, DPP executives held a meeting and confirmed the party would ask the CDP to form a single voting bloc in not only the Lower House, but also the Upper House.

"We have proposed since last year the creation of a large bloc of opposition parties," Tamaki said. "I believe we have to join forces not only in the Lower House, but also in the Upper House."

Pressed to explain the CDP's change in position, a party executive said that forming a joint voting bloc would make it easier to coordinate contenders for the next Lower House election and ensure that all the major opposition parties back the same candidate.

While the CDP has even cozied up to the Japanese Communist Party in its efforts for greater cooperation in elections, the initial voting bloc in the Lower House would begin with the three entities.

But sharp differences over policy, such as nuclear energy, will likely cloud matters somewhat.

(This article was written by Taro Nakazaki and Daizo Teramoto.)