From the mid 9th century to the 10th century, the conventional administration based on the ritsuryo system (such as henko-sei, the organization of the citizens, and handen-sei, the ritsuryo land-allotment system) faced its organizational limit, and the central government promoted a nation-wide reform of the system to reflect the actual social situations in order to maintain the level of the tax revenue.
9世紀中期～10世紀頃になると、従来の律令制（編戸制・班田制など）による統治に限界が見られるようになり、中央政府は租税収入を確保するため、社会の実情に即した国制改革を進めた。