Exterior walls of Tenshu were decorated by Shitamiita-bari (weather-board lined) of black lacquer, Kuroboku soils (black soils rich in humus content) or persimmon juice coatings, or Okabe finishing of Shikkui-nurigome (solid plastered fire-resistant wall).
天守の外壁は黒漆または黒墨や柿渋塗りの下見板張（したみいたばり）と漆喰塗籠（しっくいぬりごめ）の大壁仕上げがある。