The mailboxes for this apartment building are just above this. Can you imagine the fun of reaching over this for your mail?
Handling trash in a large urban area where there is little storage space and relatively infrequent pick-up is a tricky business. It is complicated by the fact that crows in Japan will pick trash apart if the bags are left out in an uncovered state. While there are a few places with plastic or metal dumpsters outside of their buildings, they are few and far between. Most people are expected to either keep their trash in their tiny homes until the correct pick-upday, or put the garbage in one of the cheap cages you see above. Generally, these cages are smelly, messy, and awful-looking. The cages are clearly used because they are cheaper than the dumpsters and take up less space. My guess is that landlords only offer such cages in places where tenants are constantly putting trash out too early (my building does not have one as no one puts trash out early).
I won't miss these awful trash storage areas.