There's an article in Japan Times making the argument that aversion to strangers - foreigners or Japanese - is killing rural Japan. Briefly, the argument is that as small rural or regional communities do not accept or welcome outside people that move in, it greatly discourages people from doing so. As a result, people elect to move to the cities instead (where everyone is a stranger) and the countryside suffers.
On one level the author is right. The insularity and inward-looking conservatism of rural communities is indeed one reason people choose not to move in - and why young rural people elect to live and work in culturally and socially open cities instead. the overall premise is wrong, however.
First, this is not in any way, shape or form a Japanese phenomenon. Rural, small communities everywhere are insular and indifferent, even hostile, to strangers. If I would move to a village in central Sweden I would not be accepted as one of them, ever. Sure, people may be friendly, but I would not be a villager, I'd be an outsider for the rest of my life. Try to move into small communities in France, or Eastern Europe, or America - it's all the same, with only the surface attitude differing from place to place.
And it's not this hostility per se that is killing rural Japan either; it may slightly hasten the trend but it's not causing it. As I've argued before, Japan is considerably more rural than other, comparable industrial economies, and the shift to a mostly urban economy is still ongoing. Economic and social opportunities have shifted towards urban life today, and the countryside would decline whether villagers were friendly to outsiders or not. I expect the Japanese rural population to further decline by almost half, simply to bring Japan in line with the average of other industrialized economies.
Communities being friendly or hostile may affect the future of those particular communities. But it will only help decide where rural people will still live in the future, not how many rural inhabitants the country will have overall.