Nijo-jo (1603) is the Kyoto residence of the Tokugawa shoguns. Its purpose was to project the Shogun's power into the heart of Imperial Kyoto. In practice, the castle was used infrequently: in 1603, for the investiture of Tokugawa Ieyasu; and in 1626, for a meeting between Tokugawa Iemitsu and his brother-in-law, emperor Go-Mizuno'o. The last shogun, Tokugawa Keiki, abdicated here in 1868 to Emperor Meiji.
This photo shows the outer wall and moat of the castle.