One of them hosts a bell (Shoro Tower - on the right side, when looking from outside) and the other one houses a big drum (Koro Tower).
From a distance they look the same, but on a closer look, the Shoro Tower, pictured here, is ornamented with more sculptures, representing cranes, dragons, and giraffes.
EXIF info:
Nikon D80
Lens: VR 18-55mm F/3.5-5.6G
Focal Length: 24mm
Aperture: F/5.6
Shutter Speed: 1/100s
ISO Sensitivity: ISO 100