TOKYO (KYODO) -- The leaders of the Democratic Party of Japan and the Japan Innovation Party agreed Friday to merge the largest and third-largest opposition parties in March in an attempt to challenge Prime Minister Shinzo Abe's ruling coalition in a House of Councillors election this summer.
After signing the merger accord with Innovation Party leader Yorihisa Matsuno, DPJ President Katsuya Okada told reporters that he will serve as head of a new party until the upper house poll.
Okada pledged the new party will represent the views of people unhappy with Abe's government. He criticized Abe for "conducting pork-barrel politics and putting off tackling difficult issues."
Matsuno advocated "drastically pushing forward administrative reform" so that the government does not need to impose a heavier tax burden on the public.
Altogether, about 150 lawmakers from both chambers of the Diet will join the new party, but it will still be far smaller than the ruling coalition of Abe's Liberal Democratic Party and the Komeito party, which controls a majority of the 242-member upper house and more than two-thirds of the 475-member House of Representatives.
The DPJ and the Innovation Party hope members of other parties and groups will also join the new party to more widely assemble opposition forces.
The two parties will now start talks on a party name and platform. While the Innovation Party would prefer a brand new name, some DPJ lawmakers are insisting on maintaining the DPJ's name.
Stressing that the merger deal is only a start, Matsuno said he is happy that he has taken a step with Okada toward a change of government.
Citing an agreement involving the two parties and three other opposition parties to launch talks on forging a united front against the Abe government, Okada said he "wants to run the new party and this five-party agreement in parallel so as to firmly confront Abe's politics and live up to people's expectations."
"We would like to make today a historic day from which to turn the tide of Japanese politics," he said.
In a meeting earlier this week, the DPJ, the Innovation Party, the Japanese Communist Party, the Social Democratic Party and the People's Life Party affirmed coordination in fielding unified candidates in single-member electoral districts in the upper house election likely to be held in July.
In a related move, DPJ lower house member Takako Suzuki said Friday that she will leave the party because of its election cooperation with the JCP despite wide policy differences.
Suzuki has criticized the DPJ for teaming up with the JCP and other opposition parties to field a unified candidate for a lower house by-election for the Hokkaido No. 5 district on April 24. She was elected in the Hokkaido proportional representation block.
Commenting on the opposition move, Abe said at a Diet session what is important for a political party is "not the name but whether it possesses solid principles and policies, and whether it can implement them in line with (voters') trust."