TOKYO — Kyoko Hasegawa and Natsuko Fukue China hawk Sanae Takaichi won the leadership of Japan’s ruling party today, putting her on course to become the country’s first woman prime minister.

The 64-year-old, whose hero is Margaret Thatcher, is charged with reviving the ailing Liberal Democratic Party (LDP) as a new anti-immigration grouping snaps at its heels.

The arch-conservative will almost certainly be approved by parliament as Japan’s fifth prime minister in as many years, a step that local media say could come the week of October 13.

She was elected LDP president on Saturday after winning a run off vote against the telegenic but inexperienced Shinjiro Koizumi, the son of a former premier.

Koizumi, 44, would have become Japan’s youngest prime minister in the modern era and would have represented a generational change for the LDP.

The two went into the run off after the moderate Yoshimasa Hayashi, dubbed “Mr. 119” after Japan’s emergency phone number, was knocked out along with two other candidates.

Takaichi now faces a host of complex issues including an ageing population, geopolitical upheaval, a faltering economy and growing unease about immigration.

First, however, she will have to ensure that the LDP, which has governed almost non-stop since 1955, can rally voters again.

“The LDP must regain trust, and an overhaul is needed for us to start afresh,” Koizumi had said in the campaign, calling the state of the party a “crisis”.