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 Kōmei
Emperor Kōmei was the last Japanese Emperor who had more than one era name ("nengō") during a single ruling term. Beginning with his successor, Emperor Meiji, a single era name (identical to the Emperor's official title) was selected and did not change until his death. There were seven "nengō" during Kōmei's reign.