From the late Edo period to the early Meiji era, Shin Buddhist monks such as Shimaji Mokurai (島地黙雷), Ōzu Tetsunen (大洲鉄然), Akamatsu Renjō (赤松連城), and Kagawa Hōkō (香川葆晃) achieved remarkable political prominence. After Gesshō’s (月性) death, they carried on his legacy by participating directly and indirectly in the anti-shogunate movement. After the Meiji Restoration, they promptly moved to Kyoto to initiate reforms in Hongwanji’s (本願寺) religious administration. Furthermore, they opposed the Buddhism abolition movement (廃仏毀釈) and the new Meiji government’s policy of establishing Shinto as the state religion. Throughout this process, they consistently used Shin Buddhism as an example, arguing to new government officials from Chōshū/Yamaguchi like Kido Takayoshi that Buddhism was a religion essential to the new state. The author introduces over forty newly discovered official appointments and certificates received by Hōkō, the least researched of these four Chōshū-affiliated Shin Buddhist priests who played such active roles, and explains the historical context of each document.