Because of a large-scale preparation of the capitals, such as Fujiwara-kyo Palace, Heijo-kyo Palace and Heian-kyo Palace, the compulsion of concentrated dwelling of powerful regional clans and nobles from their local lands into the capitals, and the preparation of the official roads for tax payments and government officials, (refer to the ancient roads of Japan), the provinces surrounding Kyoto and Nara (Kinai region) had become an economic area in which the wealth of Japan was concentrated.
藤原京・平城京・平安京などの大規模な首都整備、豪族・貴族の在地から首都への集住強制、納税や官人の往来のための官道整備（→日本の古代道路）などにより、畿内は日本の富が集中する経済地域となっていった。