The Yemishi are identified with the modern Ainu. It appears that the continental immigrants into Japan applied to the semi-savage races encountered by them the epithet "Yebisu" or "Yemishi," terms which may have been interchangeable onomatopes for "barbarian." The Yemishi are a moribund race. Only a remnant, numbering a few thousands, survives, now in the northern island of Yezo. Nevertheless it has been proved by Chamberlain's investigations into the origin of place-names, that in early times the Yemishi extended from the north down the eastern section of Japan as far as the region where the present capital (Tokyo) stands, and on the west to the province now called Echizen; and that, when the Nihongi was written, they still occupied a large part of the main island.
We find the first mention of them in a poem attributed to the Emperor Jimmu. Conducting his campaign for the re-conquest of Japan, Jimmu, uncertain of the disposition of a band of inhabitants, ordered his general, Michi, to construct a spacious hut (muro) and invite the eighty doubtful characters to a banquet. An equal number of Jimmu's soldiers acted as hosts, and, at a given signal, when the guests were all drunk, they were slaughtered. Jimmu composed a couplet expressing his troops' delight at having disposed of a formidable foe so easily, and in this verselet he spoke of one Yemishi being reputed to be a match for a hundred men.
Whether this couplet really belongs to its context, however, is questionable; the eighty warriors killed in the muro may not have been Yemishi at all. But the verse does certainly tend to show that the Yemishi had a high fighting reputation in ancient times, though it will presently be seen that such fame scarcely consists with the facts revealed by history. It is true that when next we hear of the Yemishi more than seven and a half centuries have passed, and during that long interval they may have been engaged in a fierce struggle for the right of existence. There is no evidence, however, that such was the case.
On the contrary, it would seem that the Japanese invaders encountered no great resistance from the Yemishi in the south, and were for a long time content to leave them unmolested in the northern and eastern regions. In A.D. 95, however, Takenouchi-no-Sukune was commissioned by the Emperor Keiko to explore those regions. He devoted two years to the task, and, on his return in 97, he submitted to his sovereign this request: "In the eastern wilds there is a country called Hi-taka-mi (Sun-height). The people of this country, both men and women, tie up their hair in the form of a mallet and tattoo their bodies. They are of fierce temper and their general name is Yemishi. Moreover, the land is wide and fertile. We should attack it and take it." [Aston's translation.] It is observable that the principal motive of this advice is aggressive. The Yemishi had not molested the Japanese or shown any turbulence. They ought to be attacked because their conquest would be profitable: that was sufficient.