Trash Finder is a map of public trash cans, toilets, water points and smoking areas across all 47 prefectures of Japan, with what each one takes and whether you are allowed to use it. The map needs JavaScript; the same data is readable without it:

Japan by the numbers — every prefecture, how many points are on record and how many have been checked
Questions people ask — where to throw things away in Japan, in one page
Stations — bins near major stations, with walking time
How it works — what "checked" means and how points are ranked
Open data — the whole dataset as JSON (OpenStreetMap contributors, ODbL)

Where to put it in Japan — which bin takes it, whether you may use it, in eight languages