Concerning the time when the old system shifted to the system based on tax on land, there is a view asserting that the era of Kanpyo no chi (Glorious rule in the Kanpyo era), led by the Emperor Uda and SUGAWARA no Michizane, was the preparatory period for the transition to the Dynastic polity regime and Engi no chi (Reign of Emperor Daigo), led by Tokihira, was the transitional period to the Dynastic polity regime (Koji HIRATA, 2000).
なお土地課税基調体制への移行の時期について、宇多天皇及び菅原道真の主導による寛平の治を王朝国家体制への転換準備期とし、延喜の治を時平による王朝国家体制への移行期であるとする意見（平田耿二,2000など）がある。