板垣退助
In the four corners of the central hall, there are statues of Itagaki Taisuke, Okuma Shigenobu, and Ito Hirobumi who were instrumental in establishing constitutional government in Japan, and an empty pedestal. It is not clear why there is an empty pedestal. Some claim original designers could not reach consensus on whose statue to build, or that it encapsulated the idea that politics is never complete. Others say designers left it open to urge politicians today to outstrip the three grand predecessors, or that they avoided building a statue with its back to the Imperial palace. The empty pedestal is displayed with a big pine bonsai on the first day of the Diet session.