Tokyo Governor Yuriko Koike has made a decision to resign as the leader of Kibo no To, or Party of Hope, which she herself launched ahead of October's general election, assuming responsibility for the party's electoral defeat.
The party also endorsed its new leadership at the meeting.
Koike established her national political party in the run-up to the October 22 House of Representatives election in an effort to defeat long-standing Prime Minister Shinzo Abe and his ruling coalition.
Koike, a former defense and environment minister, announced she was forming the Party of Hope the same day Abe said he was calling the election.
However, Koike soon came under criticism for weeding out liberal-minded members of the Democratic Party who wanted to run on the Hope ticket. She then led her party to a historic victory over the LDP in a July Tokyo assembly poll.
The LDP on its own secured well beyond the 261 threshold defined as a "stable majority" in the 465-member lower house.
That tally was not only dwarfed by the LDP's 283 seats but also lagged the 54 seats taken by the Constitutional Democratic Party of Japan (CDPJ), a group hastily formed by liberal-leaning former Democratic Party members.
The Party of Hope performed particularly poorly in the capital, where it lost in all but one district of the 23 in Tokyo in which it fielded candidates in the general election.
Koike later indicated she would concentrate on her duties as Tokyo governor and leave Hope party matters to Yuichiro Tamaki, the Lower House member who was recently elected as co-leader, and other party Diet members. "I want to step down as party leader and support you all", she told the meeting.