Emperor of Japan
The current Emperor on the throne is typically referred to as "Tennō Heika" (, "His (Imperial) Majesty the Emperor"), "Kinjō Heika" (, "His Current Majesty") or simply "Tennō", when speaking Japanese. The current Emperor will be renamed "Daijō Tennō" (, Retired Emperor), often shortened to "Jōkō" (), upon his planned retirement on 30 April 2019, and renamed "Heisei Tennō" () after his death and will then be referred to exclusively by that name in Japanese. In Japanese culture, it is considered a major faux pas to refer to a living Emperor by his posthumous name, although the posthumous name is the same as the era, which is used in official documents.
Emperor Kōrei
Kōrei is regarded by historians as a "legendary emperor" and there is a paucity of information about him. There is insufficient material available for further verification and study. The reign of Emperor Kinmei ( – 571 AD), the 29th emperor, is the first for which contemporary historiography is able to assign verifiable dates; However, the conventionally accepted names and dates of the early emperors were not to be confirmed as "traditional" until the reign of Emperor Kanmu (737–806), the 50th sovereign of the Yamato dynasty. 
In the "Kojiki" and "Nihon Shoki" only his name and genealogy were recorded. He is believed to be son of Emperor Kōan; and his mother is believed to have been Oshihime, who was the daughter of Ametarashihiko-Kunio-shihito-no-mikoto. The Japanese have traditionally accepted this sovereign's historical existence, and an Imperial "misasagi" or tomb for Kōrei is currently maintained; however, no extant contemporary records have been discovered that confirm a view that this historical figure actually reigned. He was the sixth of eight emperors without specific legends associated with them, also known as the .