In several materials and family trees edited in Sendai Domain in the Edo period, Tanemichi is regarded as the ancestor of the Kokubun clan in Mutsu Province, however, this is the only common infomation in the earlier records, and other information related to the Kokubu clan until the Sengoku period (period of warring states) widely varies.
仙台藩で江戸時代に編纂された複数の資料・系図は胤通を陸奥国分氏の先祖とするが、古い時代で一致するのは胤通だけで、戦国時代(日本)を下るまで異同がはなはだしい。