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 Go-Komatsu
He is officially considered to have been the Northern pretender from May 24, 1382 to October 21, 1392, when upon Emperor Go-Kameyama's abdication, Go-Komatsu is understood to have been a legitimate emperor (the 100th sovereign) from that date. In 1392, following the post"-Nanboku-chō" unification of the two formerly contending courts, the Southern Emperor Emperor Go-Kameyama reached an agreement with Go-Komatsu to alternate control of the throne between the Northern and Southern courts on a ten-year plan which effectively signaled the end of the southern court's claims to sovereignty. However, Go-Komatsu reneged, not only ruling for 20 years until his own abdication on October 5, 1412, but was succeeded by his own son, rather than by one from the former Southern Court. According to pre-Meiji scholars, Go-Komatsu's reign as a legitimate emperor spanned the years from 1392 through 1412. The present Japanese Imperial Family is descended from the Northern Court emperors.