Rock Chutes
Rock chute at Matsumoto-jo
You can see two rock chutes on the main keep of Matsumoto Castle above. One on the corner and one in the middle of the wall.
More Photos
Rock chutes were used to protect castles from invaders scaling the walls Rock chute at Nihonmatsu-jo
Rock chute at Hamamatsu-jo Rock chute at Matsumoto-jo