In the inscription of "Tomari Jinja Munefuda" (Plaque on Tomari-jinja Shrine), Iori explains Musashi's origin as the Shinmen clan had been prospering in Sakushu (Mimasaka Province), however, in the Tensho era, the head of the clan died in Akizuki-jo Castle of Chikuzen Province without leaving his heir, then by his will, Harunobu was adopted into the Shinmen clan as their heir, since then, Harunobu called himself Musashi;" some historians consider that the head of the Shinmen (神免) in the inscription is identical with Muni SHINMEN (新免) and Musashi was adapted to Muni (kanji character was often used in substitution for other kanji characters which had the same pronunciation); however, that opinion is doubtful since Muni had been alive after the Tensho era (1573-1592).
武蔵の養子伊織による『泊神社棟札』にある「有作州之顕氏神免者天正之間無嗣而卒于筑前秋月城受遺承家曰武蔵掾玄信」という記述から、天正年間に秋月城で亡くなった新免某を無二とし、武蔵は無二の養子となったと主張する意見もあるが、新免無二は明らかに天正年間以後も生存している。