Two explanations are offered. They are more or less conjectural. One is that the Yemishi of Mutsu were led by chieftains of Yamato origin, men who had migrated to the northeast in search of fortune or impelled by disaffection. It seems scarcely credible, however, that a fact so special would have eluded historical reference, whereas only one passing allusion is made to it and that, too, in a book not fully credible. The other explanation is that the Yemishi were in league with hordes of Tatars who had crossed from the mainland of Asia, or travelled south by the islands of Saghalien and Yezo. The main evidence in support of this theory is furnished by the names of the insurgent leaders Akuro-o, Akagashira, and Akahige. Ideographists point out that the character aku is frequently pronounced o, and with that reading the name "Akuro-o" becomes "Oro-o," which was the term used for "Russian." As for "Akagashira" and "Akahige," they frankly signify "red head" and "red beard," common Japanese names for foreigners. In a shrine at Suzuka-yama in Ise, to which point the insurgents pushed southward before Tamuramaro took the field, there used to be preserved a box, obviously of foreign construction, said to have been left there by the "Eastern Barbarians;" and in the Tsugaru district of the modern Mutsu province, relics exist of an extensive fortress presenting features not Japanese, which is conjectured to have been the basis of the Tatar invaders. But all these inferences rest on little more than hypothesis.
RISE OF MILITARY HOUSES
What is certain, however, is that a collateral result of these disturbances was to discredit the great Court nobles—the Otomo, the Tachibana, the Ki, and the Fujiwara—as leaders of armies, and to lay the foundation of the military houses (buke) which were destined to become feudal rulers of Japan in after ages. Ki no Hirozumi, Ki no Kosami, Otomo Yakamochi, Fujiwara Umakai, and Fujiwara Tsugunawa having all failed, the Court was compelled to have recourse to the representatives of a Chinese immigrant family, the Saka-no-ye. By those who trace the ringer of fate in earthly happenings, it has been called a dispensation that, at this particular juncture, a descendant of Achi no Omi should have been a warrior with a height of six feet nine inches,* eyes of a falcon, a beard like plaited gold-wire, a frown that terrified wild animals, and a smile that attracted children. For such is the traditional description of Tamuramaro. Another incidental issue of the situation was that conspicuous credit for fighting qualities attached to the troops specially organized in the Bando (Kwanto) provinces with the sons and younger brothers of local officials. These became the nucleus of a military class which ultimately monopolized the profession of arms.
*The height recorded is five feet eight inches, but as that would be a normal stature, there can be little doubt that "great" (dai) measure is referred to and that the figures indicate six feet nine inches.
RELATIONS WITH KOREA
During the eighth century relations of friendship were once more established with Koma. A Manchurian tribe, migrating from the valley of the Sungali River (then called the Sumo), settled on the east of the modern province of Shengking, and was there joined by a remnant of the Koma subjects after the fall of the latter kingdom. Ultimately receiving investiture at the hands of the Tang Court, the sovereign of the colony took the name of Tsuying, King of Pohai, and his son, Wu-i, sent an envoy to Japan in 727, when Shomu was on the throne. Where the embassy embarked there is no record, but, being blown out of their course, the boats finally made the coast of Dewa, where several of the envoy's suite were killed by the Yemishi. The envoy himself reached Nara safely, and, representing his sovereign as the successor of the Koma dynasty, was hospitably received, the usual interchange of gifts taking place.
Twenty-five years later (752), another envoy arrived. The Empress Koken then reigned at Nara, and her ministers insisted that, in the document presented by the ambassador, Pohai must distinctly occupy towards Japan the relation of vassal to suzerain, such having been the invariable custom observed by Koma in former times. The difficulty seems to have been met by substituting the name "Koma" for "Pohai," thus, by implication, admitting that the new kingdom held towards Japan the same status as that formerly held by Koma. Throughout the whole of her subsequent intercourse with the Pohai kingdom, intercourse which, though exceedingly fitful, lasted for nearly a century and a half, Japan uniformly insisted upon the maintenance of that attitude.