The mention of “denmon” in the text refers to the east gate of the outer wall. It is a wooden document that requests the government office to provide alcohol to the technicians called “shōchō” (woodworkers) who had worked on repairing the east gate. The surname of the person making the request suggests that he was likely from Shimotsuke Province (present-day Tochigi Prefecture). The wooden document says Enryaku 13 (794). At that time, there was intense conflict between Emishi and the ritsuryō state in Mutsu Province. Tensions were also rising in Dewa Province where Akita Fort was, so it is thought that technicians were dispatched there from the Kantō region to repair the castle and prepare for war with Emishi.