The Marunouchi business district, the national government center of Kasumigaseki, and the Diet building in Nagatacho all stand on land that in the Edo Period (1603-1868) was reserved exclusively for daimyo lords.
The daimyo were territorial lords that ruled in provincial domains. Under a peculiar system of political control enforced by the Tokugawa Shogunate, they were required to live in Edo in alternate years, where they maintained large residences in the city. These spacious places were surrendered to the emperor as a result of the 1868 Meiji Restoration and were conveniently used by the new government as they set up a new political and administrative structure based on the 19th-century Western model.
Lord Ii, daimyo of the Hikone domain (now Shiga Prefecture), lived close to the Sakurada Gate of Edo Castle on the castle's west side. The Ii family stood unflinchingly loyal to the Tokugawa shogun ever since Ii Naomasa swore his allegiance to Ieyasu in 1575. The 13th chief daimyo, Ii Naosuke, served in the highest position of the shogunate from 1850 to 1860, a virtual dictator in Japan during the period of national crisis following the arrival of Commodore Perry in 1853.