Prince Saionji Kinmochi was a Japanese politician and statesman who served as Prime Minister of Japan from 1906 to 1908 and from 1911 to 1912. He was elevated from marquis to prince in 1920. As the last surviving member of Japan's genrō, he was the most influential voice in Japanese politics from the mid-1920s to the early 1930s.

The prime minister of Japan is the head of government and the highest political position of Japan. The prime minister chairs the Cabinet of Japan and has the ability to select and dismiss its ministers of state. The prime minister also serves as the commander-in-chief of the Japan Self Defence Forces and is a sitting member of either house of the National Diet. The current prime minister is Fumio Kishida of the Liberal Democratic Party, who assumed the office on 4 October 2021.