The keep was built in s style called sotogata, considered to be the invention of Takatora, with the floors having the same shape, but each story being smaller than the one bellow it. It was cheaper and faster to build a castle in this way, and the construction was also more resistant..
EXIF info:
Nikon Df
Lens: 24-70mm F/2.8G
Focal Length: 48mm
Aperture: F/7.1
Shutter Speed: 1/648s
ISO Sensitivity: ISO 500