Edo Castle is a flatland castle that was built in 1457 by Ōta Dōkan in Edo, Toshima District, Musashi Province. In modern times it is part of the Tokyo Imperial Palace in Chiyoda, Tokyo, and is therefore also known as Chiyoda Castle . Tokugawa Ieyasu established the Tokugawa shogunate there, and it was the residence of the shōgun and the headquarters of the military government during the Edo period (1603–1867) in Japanese history. After the resignation of the shōgun and the Meiji Restoration, it became the Tokyo Imperial Palace. Some moats, walls and ramparts of the castle survive to this day. However, the grounds were more extensive during the Edo period, with Tokyo Station and the Marunouchi section of the city lying within the outermost moat. It also encompassed Kitanomaru Park, the Nippon Budokan Hall and other current landmarks of the surrounding area.

Ōta Dōkan , also known as Ōta Sukenaga, was a Japanese samurai lord, poet and Buddhist monk. He took the tonsure as a Buddhist priest in 1478, and he also adopted the Buddhist name, Dōkan, by which he is known today. Dōkan is best known as the architect and builder of Edo Castle in what is today modern Tokyo; and he is considered the founder of the castle town which grew up around that Ōnin era fortress.