Overcoming heated arguments, two young opposition parties planning to merge later this month finally agreed Wednesday to name their new entity Ishin no To.

In what appeared to be a fight over which side should take the initiative in party management, Nippon Ishin no Kai (Japan Restoration Party) and Yui no To (Unity Party) combined both names to come up with the moniker.

The final choice, which translates loosely as Restoration Party in English, came from three candidate names proposed by the two parties' executives to their members.

Earlier in the day, Nippon Ishin and Yui no To executives failed to even decide on the three candidate names. Yui no To rejected the ideas proposed by the other party, saying the names were too similar to Nippon Ishin's current name.

The tussle became so acrimonious that some Nippon Ishin members even brought up the possibility of calling off the merger.

In the end, Nippon Ishin decided to continue the negotiations by proposing another name to Yui no To members.

"These are birth pains (when creating a new party), and we want to overcome those difficulties," Yorihisa Matsuno, who leads Nippon Ishin's Diet lawmakers' group, told reporters after the name was decided.

Nippon Ishin's top leader, Osaka Mayor Toru Hashimoto, and Yui no To chief Kenji Eda had agreed Sunday to include the word "Ishin" in the name of the new party.

When Nippon Ishin combines its 38 Diet members with Yui no To's 14 on Sept. 21, the new party will be the second-largest opposition force in the Lower House, trailing only the Democratic Party of Japan.