The Chrysanthemum throne is the oldest monarchy in the world. It is said that the Empire of Japan was founded in 660BC by the Emperor Jimmu Tenno and his descendants continue to reign today; the current Emperor Akhito (Heisei Tenno) who is the direct 125th descendant of Jimmu. Despite the fact that there has been eight Empresses, under Japanese Imperial law (promulgated by the Imperial Household Agency and the Privy Council) woman cannot reign as sovereign.
The Japanese monarchy is highly traditional and modern at the same time. The Emperor, the Tenno (Heavenly sovereign), acts as a high priest in the Shinto faith, although his divine power was renounced after World War II.
Under the provisions of the current Japanese constitution the Emperor is a symbol of the state and the unity of the people; he has no real political power but is regarded as a ceremonial Head of State and constitutional monarch. Despite this there still exist people who would like to see the Emperor's power increase, these monarchists come in the form of politicians, Shinto fanatics and Yakuza gangsters.
The Emperor of Japan is the only Emperor left in the world, so his posistion is of historical importance not only to Japan but indeed to the world.
See also: National emblem