During the early Nara period, the land and people were governed by the central government based on the Ritsuryo system, but in 722, with the increase in population and financial demands, a large scale land development program was formulated to increase the national income by the government.
奈良時代初期は、律令に基づいて中央政府による土地・民衆支配が実施されていたが、人口や財政需要の増加に伴い、722年、国家収入を増やすため政府において大規模な開墾計画が策定された。