Although it is told that the Miyaji clan was a branch family of the Mononobe clan or a family descended from Yamato Takeru (no mikoto), the detailed genealogy related to Kunihira is unknown.
宮道氏は、物部氏庶流ともヤマトタケル末裔とも伝えられる氏族であるが、国平の系譜関係は不明である。