In this photo, behind the surrounding walls and right in front of the iconic donjon, you can see three of them: looking from the left side is the "Nishi Kotenshu" turret, connected by the "Ha Watariyagura" passage to the "Inui Kotenshu" turret.
EXIF info:
Nikon Df
Lens: 14mm F/2.8D
Focal Length: 14mm
Aperture: F/7.1
Shutter Speed: 1/1600s
ISO Sensitivity: ISO 400