I added a tag for bicycling in Japan: https://bicycles.stackexchange.com/questions/tagged/japan
This follows the same for the UK: https://bicycles.stackexchange.com/questions/tagged/uk
I'm not sure how many of these regional geographic tags we need. Perhaps we should just let usage drive it, even though I think we should add a NZ tag for Criggie. :)
I should note that the "regional" tag (https://bicycles.stackexchange.com/questions/tagged/uk+regional) only points to UK regional questions.
Should we delete "regional" and just let people use specific geographic tags? I don't think that we should either pre-populate geographic areas, but just see where demand drives it. The only significant geographic area that I would see emerging in the current would be "Netherlands" given the peculiarity of their bicycle culture.