Yamagata Aritomo, Japanese Field Marshal and politician, 3rd and 9th Prime Minister of Japan (died 1922)

Prince Yamagata Aritomo was a Japanese politician and general who twice served as prime minister of Japan (. He was also a leading member of the genrō, a group of senior courtiers and statesmen who dominated the politics of Japan during the Meiji era. As the Imperial Japanese Army's inaugural Chief of Staff, he was the chief architect of its nationalist and reactionary ideology, which has led some historians to consider him the "father" of Japanese militarism.

The prime minister of Japan is the head of government 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.