If, however, the extent of the Japanese dominions suffered reduction in the west, it in the meantime received an increment in the north by the subjection of some recalcitrant tribes. It will be recalled that the uprising of these people, called Emishi, or _Ebisu_, had been suppressed by Prince Yamato-dake, but further north in the island of Ezo, the present Hokkaidō;, the imperial sway received only partial acknowledgment. There the Emishi not only were restless, but also generally had the sympathy and support of their kinsmen across the waters, just as in earlier times, the Kumaso, the autochthons of Kiushū, habitually espoused the cause of Korea in any conflict between the latter and Japan. The government always found itself compelled to undertake a dual campaign in times of trouble with the island on the north or with the peninsula on the west. Because of these difficulties forts were built, about 650, at Nutari and Iwafune in Echigo, and garrisoned by the people of that province and of Shinano, for the purpose of holding the aborigines of Ezo in control. The unsettled condition of these outlying districts may be further inferred from an enactment contemporaneous with the great Taikwa reforms. For whereas a general interdict was then issued against unauthorized possession of arms and armor by private persons, dwellers in the remote parts of the east were exempted from this prohibition on the ground of their liability to attack. During the years 658-660, in the Empress Saimei's reign, Abe-no-Hirafu, a distinguished governor of the Koshi provinces (Echigo and Uzen), conducted successful campaigns against the autochthons of Ezo, breaking their power and destroying their vessels of war, and finally invaded Manchuria at the head of a force composed of subjugated Emishi, and cut off the source from which insurgents had usually derived succor. The result of this campaign was that the Emishi were, for the most part, brought into subjection, and functionaries called _Gunryō_; were posted at Shiribeshi in the northern island. Frequent insurrections, however, followed, and finally it was found necessary to build the castles of Taga and Akita, where strong forces of soldiers were maintained to preserve order.