score:5
Most Japanese people wonβt do that but there are exceptions all around. Besides, Japanese wonβt judge visitors/foreigners. So, you should refrain from eating in these places but a quick bite while waiting for buses/trains wonβt hurt.
Upvote:5
It's not well-mannered but neither is it unforgivable. However, if you say "standing out on a street corner" I'd say that at least you should stand somewhere with less traffic and movement. Streets can be crowded and nobody wants to get food or drink spilled on them if they bump into you, and it will be seen as much ruder if you are doing so in a crowded place.
In order of preference:
And as a general rule, if it's a larger meal or it requires utensils to eat, you should be sitting down. The above mostly applies to small snacks you can eat with your hands (e.g. rice balls, chicken pieces, etc.).