For this reason, in order to cover the expenses of such incidental events, from the late tenth century, a particular province was designated as a ryogoku and the kokushi (governor) of that ryogoku imposed temporary tasks mainly on the owners of koden (or kokugaryo - territories governed by a provincial government office).
そこで、10世紀後期ごろから、臨時の事業の費用を賄うため、ある国が料国（りょうごく）として指定され、料国の国司は主に公田（国衙領）を対象として臨時雑役を課するようになった。