Katsunari MIZUNO, Ieyasu TOKUGAWA's younger cousin, took over the position of the governor of Bingo-Fukuyama Domain from the Fukushima clan, and set up a 'bugyosho' (Tomo Rural Magistrate Office) at the site of the ruined Tomo-jo Castle.
その後、福島氏に代わり、徳川家康の従弟水野勝成が備後福山藩の領主となり、鞆城跡には奉行所（鞆奉行所）が設置された。