Nippon Ishin no Kai (Japan Restoration Party) co-leader Shintaro Ishihara said Thursday that he will soon launch a party "more conservative" than the ruling Liberal Democratic Party, allowing torn Nippon Ishin to merge, as planned, with a center-left party and perhaps trigger a sweeping realignment of the opposition.

In a Tokyo news conference, Ishihara, 81, said he and some of his followers are leaving because they disagree with the proposed merger with Yui no To, which opposes Ishihara's call to replace the Constitution.

The former Tokyo governor said there are "huge gaps" between his views and those of Yui no To on constitutional issues and the ongoing debate on legalizing the use of collective self-defense.