I wrote before about ishi-otoshi, one of the last-line defenses used by the Japanese castles. Ishi-otoshi were narrow openings used to allow defenders to throw stones and boiling oil over the attackers and were usually camouflaged.
Two such structures can be seen in this photo of the Bitchu Matsuyama castle. In the front, the yagura turret features on two sides a sort of wooden skirt, a rather obvious ishi-otoshi. A better camouflaged one is visible on the main tower, at the base of the first floor’s window.
Yesterday’s Japan Photo: