Vaccination minister Taro Kono is known for his outspokenness, reform-minded views and social media savvy, making him the most popular pick in opinion polls for future prime minister.

Kono's Japanese account on Twitter has 2.4 million followers, making him the most followed lawmaker in the country. But he has toned down his signature reform-minded policies such as phasing out nuclear energy and allowing imperial family members in the matrilineal line to ascend the Chrysanthemum Throne to gather support from the Liberal Democratic Party's conservative wing.

A Georgetown University graduate, the 58-year-old Kono was foreign minister between 2017 and 2019, a role in which he communicated with his counterparts in fluent English. He subsequently served as defense minister for a year.

An eight-term lower house member, Kono was born into a family of politicians. His father Yohei Kono issued an apology statement in 1993 as chief Cabinet secretary on the issue of "comfort women" who worked at Japanese military brothels. The junior Kono donated part of his liver to save his father's life in 2002.

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