On the other hand, another bank (hereinafter this is called the side bank) had been built for flood control and defense before that, and it was reinforced by the castle side after it began to hold the castle.
一方城の北東には以前から治水及び防御施設として堤（以下これを横堤と呼ぶ）が築かれており、籠城が始まると城方によってさらに補強された。