I wonder about Shibuya since I lived there. When you approach the Shibuya station area there is not a sign showing that it is a non-smoking zone but there are a dozen or two smoking areas like outside the H&M store. My guess is that it is banned like in other central wards and people ignore it elsewhere.
In the back streets between Tokyu Honten and Hands there is a commercial smoking zone under cover that is sponsored by a cigarette company. I think it's heated in the winter.
Smoking in Japan today is a rather blue collar and/or "rough character"/ rebel behavior. A lot of people who hang out in Shibuya smoke. I guess it's the same as in the West.
Originally Posted by
joejones
Most of the ward governments in Tokyo specifically ban "smoking while walking" and/or smoking on public streets, the concept being that you can still smoke outdoors (e.g. in a park, on a balcony or rooftop, in a designated smoking zone) as long as your smoke doesn't interfere with traffic. This is the gist of the rule in Chiyoda, Minato, Shinjuku and a few other wards.
There is no such ban in most of Shibuya. I am not sure what the rule is around Shibuya Station, but I see a lot of smokers walking around Ebisu, Hiroo, Yoyogi, etc.
The outdoor smoking bans in Kyoto, Osaka and other cities are also generally limited to specific central areas which are indicated by signs.