The Imperial Household of Japan is headed by the emperor. The Constitution of Japan defines the emperor to be "the symbol of the state and of the unity of the people". He performs ceremonial duties and holds no real power; not even emergency reserve powers. Sovereignty is vested in the Japanese people by the constitution. Though his official status is disputed, on diplomatic occasions the emperor tends to behave (with widespread public support, it should be noted) as though he were a head of state. In academic studies, Japan is generally considered a constitutional monarchy, based largely upon the British system.

The front entrance to the Imperial Residence in Tokyo

Akihito (明仁) is the current and 125th Emperor of Japan. He assumed the throne after the death of his father, Hirohito, on January 7, 1989. His son, Crown Prince Naruhito, married Masako Owada, who gave birth to a girl, Princess Aiko, in 2001. The Imperial Household Law of 1947 limits succession to males, but there is ongoing and widespread public discussion of the Japanese Imperial succession controversy. It seems likely that the law will be amended to permit women to ascend the throne (as eight have in Japan's recorded history).