Oota Doukan, also known as Oota Sukenaga or Oota Doukan Sukenaga, was a Japanese samurai warrior-poet, military tactician and Buddhist monk. Oota Sukenaga took the tonsure (bald scalp) as a Buddhist priest in 1478, and he also adopted the Buddhist name, Doukan, by which is known today. Doukan 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 Ounin era fortress.
Although born into the Oota clan -- and claimed by the Oota as a clan celebrity -- Doukan served as a vassal of the Ougigayatsu branch of the Uesugi clan which occupied land in the Kanto region of Honshu.
Doukan is credited with designing and building Edo Castle for Uesugi Sadamasa over the fortifications Edo Shigenaga had earlier built. Work on the defensive walls and moats began in 1457; and he took the name Doukan the following year.
In the late 16th century, Doukan's castle was chosen as the new home of Tokugawa Ieyasu, who had been persuaded by Toyotomi Hideyoshi to transfer the seat of his clan holdings into the Kanto. With the establishment of the Tokugawa shogunate in the early 17th century, Edo Castle became the center of the shogunate government. When the shogunate was displaced in the Meiji Restoration in the late 19th century, the newly named Tokyo became an Imperial capital with an Imperial Palace rising from the former shogun's stronghold. Every October 1, modern Tokyo celebrates the anniversary of its founding, which becomes a festival in honor of the memory of the samurai who would become honored as the founder of a great city.