Japanese ruins are somewhat very melancholic in comparison with the ones we find on the European or American urbex websites. Check by yourself.
Until 1972, this prison located on Sadoshima was active. Nowadays, it is open to the public, you just need to push the door and enter. This place is really pretty, I loved it.
Along a dark road covered by trees, you'll find a little but scary building topped by a long cheminee.
The Yasato Post Office is a very simple haikyo, yet cute with a nice melancholic vibe.
The Toshiba Employee Center is not a famous haikyo but it contains quite a lot of stuff: floppy disks, CDs, and other company materials.
The Yamanakako Sanyo Securities Training Center features 3 buildings: a dormitory (with an attached bath-house), a training / conference building, and a security vault.