That's crazy to me, Tokushima in Shikoku was on my short list of "ideal relocation spots". With just a few hours of scenic driving, you can be in Kochi, Takamatsu, Matsuyama, Okayama, or Wakayama. All with populations of 300,000-700,000 (so decent mid-tier cities). So you could easily geographically distribute 4-5 girlfriends across those towns and combine them with some awesome driving experiences in-between.
Osaka and Kobe aren't much further if you really want a big-city party nightlife occasionally too.
This comment took an unexpected turn. Why can you not have girlfriends in the same town?
Japan's urban population is somewhere between stagnating and declining, not increasing. The contraction trend is even worse in most of their cities other than Tokyo.
Simultaneously the percentage of the population that is urban, is very slowly increasing.
Those are two very different things. Their cities are net contracting in population. They're now nationally losing people faster than they're urbanizing. They're currently losing around a quarter of a million people per year nationally. Their cities are not expanding faster than that drop. And given their already very high urbanization rate (and very slow rate of urbanization increase), it's unlikely anything will significantly change in that regard. This decade will see either a mostly flat population trend in Tokyo, or a modest contraction. What it won't show, is a meaningful expansion, as their national population contraction gets worse.
The pandemic put enough pressure on Tokyo that it actually contracted for the first time in ~25 years.
February 25, 2021
"Tokyo, Feb. 25 (Jiji Press)--Tokyo's estimated population fell by 662 from a year before to 13,952,915 as of Feb. 1, marking its first year-on-year decline in about 25 years, the metropolitan government said Thursday."
https://www.nippon.com/en/news/yjj2021022500969/
However, if you go back further, you can see the trend was already toward decline. This is from 2019:
June, 2019, The Guardian
"Has Tokyo reached ‘peak city’?"
"One could argue that the world’s biggest city has hit a sweet spot: a flatlining population, pervasive transit and little gentrification. But is ‘peak city’ even possible – and where does Tokyo go from here?"
"Unlike many megacities, the world’s largest metropolitan area has largely stopped growing, either in land or population."
https://www.theguardian.com/cities/2019/jun/14/has-tokyo-rea...
Nope.
Japan has a declining population, but the population keeps urbanising. So while there's hefty supply (literally millions of unoccupied housing inventory) in places nobody wants to live in, there is not in places where people are moving to (large cities).
There's very regularly news and posts about unoccupied houses ("akiya") being literally given away by government and local authorities because even at auction for pennies nobody wants to bid on rural properties. There was one going through here just last week.
Some prefectures are nearing 20% vacancy rates, but they're places like… well basically all of Shikoku which is largely mountainous and rural, and has been bleeding population at a rate of 5%/decade since 2000.