Position of Sedo-ka in Hitomarro Kashu was considered in the historical view of its development, comparing with ones in two chronicles, Kojiki and Nihonshoki. Repetition of third and sixth phrase could be found commonly in both of them. But the latter could be abridged and reformed into Tanka without any change of contents and expression, so they had a close character to ones in Nara Period. Contrary repetion of Sedo-ka in Hitomarro Kashu was used necessarily for poetical expression and they could not be abridged easily. That means they had an essensial character of Sedo-ka. We could say that they prece,ded ones in two chronicles and new form of expression was established on the process of writing down according to oral tradition of dialogue poems.