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.  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 .   