With the change in the tax collecting system in the 10th century, influential classes (influential aristocracy, temples and shrines) took over private land (shieiden: lands directly governed by such powers) in many places.
10世紀前期に従来の租税収取体系が変質したことに伴い、権門層（有力貴族・寺社）は各地に私領（私営田）を形成した。