Records of heads of state
Officially, the current Emperor of Japan, Akihito is the 125th in line from the first emperor Jimmu, who is variously believed to have reigned in the 1st or 7th century BC. The earliest documentary evidence is only for the 29th emperor, Kinmei (AD 509–571); however, this is sufficient such that even the most conservative of estimates still places the Japanese imperial family as among the oldest lines in the world today.
List of Emperors of Japan
This list of Emperors of Japan presents the traditional order of succession. Records of the reigns of the Emperors of Japan are compiled according to the traditional Japanese calendar. In the "nengō" system which has been in use since the late-seventh century, years are numbered using the Japanese era name and the number of years which have taken place since that "nengō" era started.