Ihai is a policy under which the Ritsuryo-seifu Government (the ancient Japanese government of centralized governance) (Imperial court) forced Emishi (northerners), who lived in present-day Tohoku area, to move to Kanto region and to the west of Honshu, Shikoku and Kyushu from the 8th to the 9th century.
移配（いはい）とは、8世紀から9世紀にかけて、当時の日本の律令政府（朝廷）が現在の東北地方に居住していた蝦夷を内地（関東地方以西の本州・四国・九州）に強制移住させた政策のこと。