Reiwa Shinsengumi opposition party leader Taro Yamamoto, 48, won the party's first leadership contest since its foundation on Sunday. The election was held as his three-year term came to an end.
Nominees were allowed to compete as a pair or group and run as a single entity.
Other election candidates included Akiko Oishi, 45, and Mari Kushibuchi, 55 -- both members of the House of Representatives who ran as one entity -- and critic Tsunehira Furuya, 40.
Eighteen votes were counted in the contest, including nine from Diet members and others, with the rest from local legislators and supporters, among others. Out of 17 valid votes, Yamamoto led with 8.83, followed by the Oishi-Kushibuchi coalition.
"I'll do my best more than ever as more and more people are in dire straits," Yamamoto said at a press conference.
Read more from The Japan News at https://japannews.yomiuri.co.jp/