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 rulers of Japan
The rulers of Japan have been its Emperors, whether effectively or nominally, for its entire recorded history. These include the ancient legendary emperors, the attested but undated emperors of the Yamato period (early fifth to early 6th centuries), and the clearly dated emperors of 539 to the present. Political power was held in various eras by regents and "shōguns", and since 1946 has been exercised exclusively by the Prime Minister as leader of a representative government.