It is explained that the castellan might have judged that, because, same as in the case of Miki-jo Castle, the Mori clan promised to send reinforcement troops and supplied provisions through Hanakuma-jo Castle and Amagasaki-jo Castle, but no reinforcement troops did come even after one year, it was impossible to maintain if the situation remained as it was and, because sending subordinates as emissaries did not bring any result, the castellan decided to visit Aki Province by himself and directly negotiate with the Mori clan.
三木合戦もそうであったが、毛利氏は援軍の約束しながら、花隈城や尼崎城を通じて兵糧は補給していたが、1年経っても援兵はこず、このままでは城を持ちこたえるのは不可能と判断し、家臣を使者としても効果は無く、城主自ら安芸国に出向き毛利氏と直接交渉しようとしたのではないかと説明している。