However, when cannons and guns came into use, the power of bullets with gunpowder reduced the superiority of height and the relatively thin walls were destroyed easily with cannons.
しかし、大砲、銃が使われ出すと、火薬を使った銃弾の威力は高さの優位を減少させ、大砲により高いが比較的薄い壁は容易に打ち壊されるようになった。