The Constitutional Democratic Party of Japan (CDP) and the Democratic Party for the People (DPP) are seeking to cooperate in the upcoming election for the all-important House of Representatives.
With the ruling Liberal Democratic Party (LDP) in hot water due to a slush funds scandal involving the party's factions, the two opposition parties believe it is possible to strip it of its majority.
Major hurdles remain, however, such as what to do about the CDP's ties with the Japanese Communist Party (JCP) and how to overcome differences over basic policies including those on nuclear power and the Constitution.