According to the descriptions made by Gyuichi OTA and the missionary, the scale and appearances of the castle symbolized Nobunaga's task of unifying the whole country that was expressed in his policy "Unify Japan by the military government."
その規模、容姿は太田牛一や宣教師の記述にあるように天下布武、信長の天下統一事業を象徴する城郭であった。