The Constitution of Japan came into force on May 3, 1947. To commemorate this event, the date is celebrated as a national holiday.
Unlike the Meiji Constitution that it replaced, the present Constitution declares that sovereignty lies with the people; the Emperor is "the symbol of the state and the unity of the people" who has no "powers related to government." It asserts that people have fundamental human rights and renounces war.
It is a very democratic document modeled on the American and British constitutions.
The National Diet building in Tokyo. (Ministry of Foreign Affairs)
On May 3 of each year, the anniversary of the Constitution's coming into force is marked with ceremonies around the country. Thousands of people attend lectures on the role of the Constitution has played for over 50 years.
The Diet building itself is opened to visitors for this day. A lot of families walk through the halls that are usually off-limits to ordinary people, and many people are seen taking snapshots in front of the building.