The provincial governments created registers called "Ota bumi" (cadastral surveys) for all the kokugaryo, thereby getting a sense of the total agricultural land area and total yield, and so these Ota bumi became the basis of the system of taxation.
国衙領については国府が大田文と呼ばれる台帳を作成し、農地の面積や収量を把握し、徴税の基礎資料としていた。