Former Tokyo Gov. Shintaro Ishihara and Nagoya Mayor Takashi Kawamura agreed Thursday to merge their political parties and face December's general election together, and further called on Osaka Mayor Toru Hashimoto's national group and Your Party to join them.

"We must overcome small differences in order to form a large coalition, otherwise we won't be able to change the country," Ishihara told reporters in Tokyo.

Kawamura heads the Nagoya-based Genzei Nippon (Tax Reduction Japan), which has five Diet lawmakers, while Ishihara's Taiyo no To (The Sunrise Party), which was only launched Tuesday, counts five Diet members among its ranks.

Ishihara declared that he also wants Hashimoto's Nippon Ishin no Kai (Japan Restoration Party) and Your Party, a minor opposition group, to merge into a single group, saying he will discuss the matter Friday with Hashimoto.

"I'll meet with Hashimoto, and it will probably be the final meeting," Ishihara said. "I am confident that the coalition will be formed."

Following Prime Minister Yoshihiko Noda's abrupt announcement Wednesday that he will dissolve the Lower House on Friday for a general election Dec. 16, Ishihara is apparently rushing to clarify exactly where Hashimoto stands on his proposed grand coalition.