However, when it comes to the first builder, it is absolutely unknown, and rather if we were to guess, it could be someone related to Kadokawa Ito clan who occupied Agata no sho, however it is also necessary to consider the relationship with the 'Furushiro' (Old Castle), 'Nakano-jo Castle' or 'Naka no shiro Castle' mentioned later, as well as that this area was called 'Hon-mura' (main village) until recently.
しかし、最初の築城者となるとまったく不明であり、あえて推定するならば、縣荘を支配していた、門川伊東氏関連かと思われるが、後述の「古城」や「中野城」あるいは「中城」との関係や、この地域を最近まで「本村」と呼んでいたことも考慮して考える必要がある。