This change resulted in a mechanism in which an area of a field administered directly by a ruler and registered in the standardized map of provinces in the reform of the national administration from Emperor Uda to Emperor Daigo in the late ninth century was allocated to the rich and powerful class, and the tax was collected according to the area.
この変化は9世紀末の宇多天皇から醍醐天皇にかけての国政改革で基準国図に登録された公田面積を富豪層に割り当て、この面積に応じて徴税する機構として結実した。