Ōta Dōkan , also known as Ōta Sukenaga ( 太田 資長 ) or Ōta Dōkan Sukenaga , was a Japanese " samurai " warrior - poet , military tactician and Buddhist monk . Ōta Sukenaga took the tonsure ( bald scalp ) 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 ( now the Imperial Palace ) in what is today modern Tokyo ; and he is considered the founder of the castle town which grew up around that " Ōnin " era fortress . Dōkan ' s 15th century poetic description of what was once just a fortified hill on the Sumida River near Edo Bay would become the basis for metropolitan Tokyo Governor Ryokichi Minobe ' s 1971 re - election slogan : " Give Tokyo back its blue sky ! " The sky is not often blue and Mount Fuji may only be glimpsed on rare days , but the green pine trees still adjoin the continuously occupied site which Dōkan first chose . Instead of stone walls , the defense works around the 15th - century castle were only grassy embankments , and the structures inside them were not grand . The initial enclosure which served as the castle ' s core area , the space which would have been Dōkan ' s " hon - maru , " was modestly sized ; but the moats were extensive for that time period . These moats and their locations would figure prominently in the serial phases of construction and development which followed . Dōkan is also credited with diverting the Hira River east at Kandabashi to create the Nihonbashi River . Celebrations attending the 500th Anniversary of Greater Tokyo illuminated parts of the story of Dōkan ' s life and achievements ; and since that time , he has remained a well - known figure in modern popular culture . Ōta clan genealogy . The Ōta clan originated in 15th century Musashi province . They claimed descent from Minamoto Yorimasa , and through that branch of the Minamoto they claimed kinship with the Seiwa - Genji . The feudal progenitor of the clan name , Ōta Sukekuni , established himself at Ōta in Tamba province , and he adopted this location name as his own . He traced his lineage as a 5th generation descendant of Yorimasa . In a special context created by the Tokugawa shogunate , the Ōta clan were identified as " tozama " or outsiders , in contrast with the " fudai " or insider " daimyō " clans which were hereditary vassels or allies of the Tokugawas . In , 1638 , Ōta Sukemune , the grandson of Ōta Yasusuke , was granted Nishio Domain in Mikawa province ; and then , in 1645 , he and his family was transferred to Hamamatsu Domain ( 35 , 000 " koku " ) in Tōtōmi province . Yasusuke ' s descendants were moved several times by shogunate decree , residing successively in 1687 at Tanaka Domain in Suruga province , in 1703 at Tanakura Domain in Mutsu province , and in 1728 at Tatebayashi Domain in Kōzuke province . Then , in the period spanning the years 1746 through 1868 , this branch of the Ōta clan established itself at Kakegawa Domain ( 53 , 000 " koku " ) in Tōtōmi . The head of this clan line was ennobled as a " Viscount " in the Meiji period . Events of Dōkan ' s life . Although born into the Ōta clan — and claimed by the Ōta as a clan celebrity — Dōkan served as a vassal of the Ōgigayatsu branch of the Uesugi clan which occupied land in the Kantō region of Honshū . Dōkan is credited with designing and building Edo Castle for Uesugi Sadamasa ( 1443 – 1494 ) over the fortifications Edo Shigenaga had earlier built . Work on the defensive walls and moats began in 1457 ; and he took the name Dōkan the following year . Ōgigayatsu Uesugi Mochitomo ordered ordered Ōta Michizane and Dōkan to construct fortifications at Kawagoe in 1457 . As a military strategist , he is reputed to have been an effective tactician ; but political intrigues can be as deadly as any battle . Despite years of distinguished service , the Uesugi clan leader proved fickle . Dōkan met an untimely end at Uesugi Sadamasa ' s home in Sagami ( modern - day Kanagawa ) after he was falsely accused of disloyalty during a period when the Uesugi family struggled through an internal clan conflict . His death poem is as follows : Following his death , the castle was then abandoned until it was taken over by Ieyasu in 1590 . Dōkan was also well - read in classical ( Heian period ) literature ; and like other samurai of his time , Dōkan was said to have been a skilled poet , but only fragments attributed to him have survived . Dōkan is also credited with having selected the site of the Hikawa Shrine , which is dedicated to Sugawara no Michizane , the " kami " of poetry and scholarship . Hikawa Shrine is located very near Edo Castle . Legacy . Dōkan ' s residence in Kamakura became Eisho - ji , a Buddhist temple . The temple complex was s founded by Okaji , a daughter of Ōta Yasusuke who would have been one of Dōkan ' s great - great - grandsons . Okaji was one of Tokugawa Ieyasu ' s attendants , and she later became a foster mother to Tokugawa Yorifusa ( 1603 – 61 ) , the founder of the Mito branch of the Tokugawa family . After Ieyasu ' s death , Okatsu became a nun , taking the name Eishoin . The third shogun , Tokugawa Iemitsu ( 1604 – 51 ) , granted her the property her ancestors had once owned . In 1636 , Eishoin had a temple built and she invited a daughter of Yorifusa to join her . Eisho - ji ' s prosperity helped preserve the memory of the 15th century ancestor who once lived in the same place . In the late 16th century , Dōkan ' s Edo 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 Kantō . 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 . The city of Isehara celebrates Dōkan ' s contributions to the area with the annual Dōkan festival each summer .