According to the genealogical table of the Kokubun family (of Mutsu Province) that was compiled by Yoshikazu SAKUMA of Sendai Domain in the Edo period, Taneshige is said to have been the third head of the family.
江戸時代に仙台藩の佐久間義和が編纂した国分氏(陸奥国)の系図では、胤重は国分氏第3世の当主とされる。