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.
Imperial House of Japan
There are currently 18 members of the Imperial Family:
The Princess Mikasa is the widow of the Prince Mikasa (2 December 1915 – 27 October 2016), the fourth son of Emperor Taishō and Empress Teimei and an uncle of Emperor Akihito. The Princess was born on 4 June 1923, the second daughter of Viscount Masanori Takagi. Princess Mikasa has two daughters and three sons with the late Prince Mikasa.