 Emperor Akihito received the title "Daijō Tennō" (, Emperor Emeritus), often shortened to "Jōkō" (), upon his abdication on 30 April 2019, and is expected to be 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 era name, since it is only after his death when his era name becomes his posthumous name.Originally, the ruler of Japan was known as either / (Yamato-ōkimi, Grand King of Yamato), / ("Wa-ō"/"Wakoku-ō", King of Wa, used externally) or ("Ame-no-shita shiroshimesu ōkimi" or "Sumera no mikoto", Grand King who rules all under heaven, used internally) in Japanese and Chinese sources before the 7th century.