An exorbitant amount of money is required to maintain and preserve castle towers, as such work demands the traditional technique of castle building, down to each of the nails used, under the supervision of the Agency for Cultural Affairs.
その維持・保存には、文化庁の指導のもと釘一本に至るまで伝統的な城郭建築の技法を求められるため、多額の経費が必要である。