The first national holiday of Golden Week is Showa no Hi on April 29, which honours the birthday of the former Showa Emperor.
The purpose of the holiday is to commemorate the promulgation of the 1947 Constitution of Japan. The new Japanese constitution was put into effect on May 3, 1947.
The History of Kenpou Kinenbi
Constitution Memorial Day was first celebrated in 1948 to reflect on the meaning of democracy in Japan and the Japanese government. The new constitution was created during the American occupation of Japan after World War II, with representatives from many countries contributing to the design of the new constitution and parliamentary form of government which was to follow.
This is the only day of the year that the National Diet Building is open to the public as well.