Takaichi, who is known to be an admirer of Britain's Margaret Thatcher, will get an early opportunity to meet President Donald Trump. They are both due to attend a meeting of the Asia Pacific Economic Cooperation forum in South Korea at the end of October, and they should find common cause on conservative issues such as immigration.

Hardline conservative Sanae Takaichi has been elected Japan's first female prime minister after a whirlwind few weeks of political wrangling.

“Political stability is essential right now,” Takaichi said at Monday’s signing ceremony with the JIP leader and Osaka Gov. Hirofumi Yoshimura. “Without stability, we cannot push measures for a stron...