Government of Japan
The Current Emperor of Japan (今上天皇) is Akihito. He was officially enthroned on November 12, 1990. He is styled as "His Imperial Majesty" (天皇陛下), and his reign bears the era name of Heisei (平成). Naruhito, the Crown Prince of Japan, is the heir apparent to the Chrysanthemum Throne.
Emperor of Japan
There are two Japanese words equivalent to the English word "Emperor": "tennō" (, "heavenly sovereign"), which is used exclusively to refer to the Emperor of Japan, and "kōtei" (皇帝, the title used for all other foreign Emperors), which is used primarily to describe non-Japanese Emperors. "Sumeramikoto" ("the Imperial person") was also used in Old Japanese. The term "tennō" was used by the Emperors up until the Middle Ages; then, following a period of disuse, it was used again from the 19th century. In English, the term "mikado" ( or ), literally meaning "the honorable gate" (i.e. the gate of the imperial palace, which indicates the person who lives in and possesses the palace), was once used (as in "The Mikado", a 19th-century operetta), but this term is now obsolete. (Compare Sublime Porte, an old term for the Ottoman government.)