The streets and sidewalks are immaculately clean in Japan. Even in the busy metropolitan areas. You’d think that with so few trash bins around, the streets would be absolutely littered, but that is not the case at all. It’s so clean that it makes one feel bad to be the first one to sully the sidewalks with their own trash, and that guilt will help one hold onto their unnecessary baggage until they do come across a garbage can.
I come from the big city of New York, and there are plenty of trash cans around, but there is also plenty of trash on the ground. The thing is that people just don’t care. People will eat and drink on the go and drop their wrappers while noone is looking. But in Japan, whether eyes are watching or not, people will suck it up and carry their trash. But they don’t really eat and travel at the same time.
There are many convenience stores in Japan, and most have trash cans either inside them or directly outside. The idea is that you will buy something from that store, eat there, and throw away your trash there too before moving on with your day. It’s not like people aren’t in a rush, because they definitely are. But they do value 5 or 10 minutes of peaceful immobility to enjoy their meal or smoke.
In fact, cigarette butts probably comprise 80% of the litter you will see from time to time. Smoking and walking isn’t allowed technically, but it is not an enforced rule, and people get rid of their butts as soon as they are done in the location that they finish. I don’t condone it, so you should definitely not do this when you are here. There are no trash cans in parks due to bomb/terrorist threats and people throwing their home trash away in them historically, so most people will often carry around a spare plastic bag to temporarily throw away their trash in until they find a more permanent solution. These are wonderful practices that I wish other people around the world participated in. It would make the neighborhoods so much prettier.