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.
Government of Japan
The Emperor is known to hold the nominal ceremonial authority. For example, the Emperor is the only person that has the authority to appoint the Prime Minister, even though the Diet has the power to designate the person fitted for the position. One such example can be prominently seen in the 2009 Dissolution of the House of Representatives. The House was expected to be dissolved on the advice of the Prime Minister, but was temporarily unable to do so for the next general election, as both the Emperor and Empress were visiting Canada.