TOKYO (Reuters) - The governor of the Japanese capital, Tokyo, whose opposition “Party of Hope” came a distant third to Prime Minister Shinzo Abe’s ruling party in a general election last month, said on Tuesday she would quit as party co-leader.

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Governor Yuriko Koike, a former ruling Liberal Democratic Party (LDP) lawmaker sometimes mentioned as a possible first female Japanese premier, launched the party to great fanfare ahead of the Oct. 22 lower house election and absorbed a big chunk of the failed opposition Democratic Party.

But despite her bid to create what she called a “reformist, conservative” rival to Abe’s LDP, Koike’s party won only 51 seats 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.

Koike announced her decision at a televised meeting of her party legislators, also attended by Yuichiro Tamaki, who was recently elected as Party of Hope co-president.

“I want to step down as party leader and support you all,” she told the meeting.

“I want to leave things to President Tamaki.”

A media-savvy former TV announcer and veteran lawmaker who served as environment and defense minister, Koike defied the LDP to run for Tokyo governor last year and trounced her ruling-party rival.

She then led her party to a historic victory over the LDP in a July Tokyo assembly poll.

But support for the Party of Hope faltered after Koike said she would “exclude” liberal members of the Democratic Party and decided not to seek a seat in parliament herself.

She also confused many voters by seeming to leave open the possibility of a tie-up with the LDP after the general election.

Support for the Party of Hope was a mere 3.2 percent against 9.3 percent for the CDPJ and 37.1 percent for the LDP, in an NHK survey released on Monday.

Abe has had a bounce in his ratings, a series of public opinion polls published this week indicated, but his support remains below 50 percent.

The NHK survey put support for his cabinet at 46 percent, a seven point rise from a September survey, with the most frequently given reason being “it’s better than other cabinets”.