Sori-daijin Kantei is the working office for the Prime Minister of Japan.
National Diet Building is the place in which both the houses of the Diet of Japan (similar to a parliament) are held with the House of Representatives in the left wing and the House of Councillors in the right wing. The National Diet Building was completed in 1936, however a series of designs were being contemplated as far back as 1886. The design of the National Diet Building is really a hybrid of several of the entrants to a design competition with the floor plan being based on the designs of the competition winner Watanabe Fukuzo, while the roof line including the tower was based on third placed entrant Takeuchi Shinshichi. Visitors can tour the House of Councillors, but an invitation is required from a member to tour the House of Representative.