On 10th the Tokugawa side sent a yabumi (letter affixed to an arrow) with a message recommending them to surrender, and on 11th mobilized mine workers in Kai Province and Sado Province to begin to dig tunnels to destroy earthen walls/stone walls from the south side (the old calendar).
10日には降伏を促す矢文を送り、11日には甲斐国や佐渡国の鉱夫を動員して南方より土塁・石垣を破壊する為の坑道掘削を始めた。