A suited woman, filmed from behind, walks down a corridor towards the light. Her heels ring on the floor. She passes two old men, wreathed in cigarette smoke. “Oppose us, will you?” they say. “Make a fool of the organisation?” The woman walks straight past. Four young men fall in behind her as she enters the light. Her face we never see, because we do not need to. The iconography, the silhouette and the story are unmistakable to every voter in Japan: Yuriko Koike.

Landing on unsuspecting prime minister Shinzo Abe like a slap from a sumo wrestler, the brief online video launched Ms Koike’s new Party of Hope, which will contest a general election called for October 22. Within 72 hours of her launch, Japan’s main opposition party collapsed, establishing Ms Koike as the main rival to Mr Abe’s ruling Liberal Democrats. The 65 year-old has still not said whether she will quit her job as Tokyo governor and stand for parliament. Nonetheless, she is within touching distance of becoming the first female prime minister of Japan. 

That would mark the spectacular culmination of a career spent running against a grey, male establishment using a mixture of charm, media-savvy, ruthless power politics and a gambler’s sense of timing. “What she has is decisiveness and guts,” says Takatane Kiuchi, a member of parliament who has defected to the Party of Hope.