Japan's first female prime minister, Sanae Takaichi, is using personal gifts and entertainment to build rapport with foreign leaders. Her unique approach to diplomacy is being tested as she settles into her role.

Japanese Prime Minister Sanae Takaichi has been putting her own spin on omotenashi, the Japanese concept of hospitality, to build personal rapport with foreign leaders as her diplomatic skills are put to the test about six months into office. Takaichi, Japan’s first female prime minister, who was not widely known for her diplomatic experience before taking office, has been adding an element of entertainment to summit talks and relying on personal gifts to win over her counterparts. Most...