Emperor of Japan
Currently, the Emperor of Japan is the only head of state in the world with the English title of "Emperor". The Imperial House of Japan is the oldest continuing monarchical house in the world. The historical origins of the Emperors lie in the late Kofun period of the 3rd–7th centuries AD, but according to the traditional account of the "Kojiki" (finished 712) and "Nihon Shoki" (finished 720), Japan was founded in 660 BC by Emperor Jimmu, who was said to be a direct descendant of the sun-goddess Amaterasu. The current Emperor is Akihito. He acceded to the Chrysanthemum Throne upon the death of his father, Emperor Shōwa (Hirohito), in 1989. The Japanese government announced in December 2017 that Akihito will abdicate on 30 April 2019.
Head of state
The was drawn up under the Allied occupation that followed World War II and was intended to replace the previous militaristic and quasi-absolute monarchy system with a form of liberal democracy parliamentary system. The constitution explicitly vests all executive power in the Cabinet, who is chaired by the prime minister (articles 65 and 66) and responsible to the Diet (articles 67 and 69). The emperor is defined in the constitution as "the symbol of the State and of the unity of the people" (article 1), and is generally recognized throughout the world as the Japanese head of state. Although the emperor formally appoints the prime minister to office, article 6 of the constitution requires him to appoint the candidate "as designated by the Diet", without any right to decline appointment. He is a ceremonial figurehead with no independent discretionary powers related to the governance of Japan.