After the Jokyu War in 1221 (in which the Retired Emperor Gotoba who hatched a plot to overthrow the Bakufu issued an order to defeat Yoshitoki HOJO but failed and was banished to Oki Province), the Kamakura government started to hold decisive political power, making Kamakura the seat of administration of Japan both nominally and virtually.
承久3年（1221年）の承久の乱（後鳥羽上皇が倒幕を企て、北条義時の追討を命じるが、失敗して隠岐に配流される）以後、鎌倉側の政治的優位は決定的となり、鎌倉は名実共に、日本の行政府所在地となったといえる。