What to watch for in Japan's leadership vote Wednesday

FILE PHOTO: Candidates for the presidential election of the ruling Liberal Democratic Party, Taro Kono, the cabinet minister in charge of vaccinations, Fumio Kishida, former foreign minister, Sanae Takaichi, former internal affairs minister and Seiko Noda, former internal affairs minister, attend a debate organized by the Liberal Democratic Party, Youth Bureau, Women's Bureau at the party headquarters in Tokyo, Japan, September 20, 2021. Philip Fong/Pool via REUTERS

(Reuters) - Japan's ruling party votes for a new leader on Wednesday in an unusually unpredictable tussle that will essentially decide the next prime minister of the world's third largest economy.

Four candidates are in the running to lead the Liberal Democratic Party, including the popular vaccine minister Taro Kono, 58, and the centrist ex-foreign minister Fumio Kishida. Two women will also historically vie for the top job, including the ultra-conservative Sanae Takaichi, 60, and Seiko Noda, 61, from the party's dwindling liberal wing.