Where did the northmost border of Japan run in the late 12th century (the beginning of the shogunate era)

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No, I was just surprised to know that along with the Japanese the Honsyu was inhabited by the other ethnic groups such as Hayato, Emishi, Kumaso etc. Many of them had not been assimilated until as late as the High Medieval.

Thank you very much for your answer. Yes, I knew that Hayato and Kumaso lived in the south. I was not only sure whether they were ethnic subgroups of the Yamato continuum. You resolved my doubts, thanks! ) I was only surprised to know that the Yamato empire had not been initially spread over the whole Honsyu, because earlier I thought it had been. I read that the Nara and Kyoto courts settled over to the North Honsyu about 19 tsd peasant households but I am still in doubt whether it meant the legal resident population or if they were just like the frontiers in America. Anyway it interests me in cultural and proper in architectural matter. I just want to know the heartland of Japan, where the most ancient architectural treasures are concentrated (not later than 13th century). For xample, are there any surviving surface buildings (temples, castles, palaces, civil facilities etc) since the Heian period in the north from Tokyo. And by the way, in Kyusyu too.