Partly because the criteria and examinations became gradually stricter regarding restoration of structures around that time in the historic castle sites, which were regulated by the Agency for Cultural Affairs, externally restored Tenshu with modern materials and construction methods should, in a narrow sense, be included in the category of reconstructed Tenshu.
文化庁の定める城郭史跡における当時の建造物復元に関し、基準・審査が厳しくなっていったこともあり、近代の材料・工法による外観復元天守も厳密には復興天守に入ることになる。