Wow, that huge for Japan I believe.
I live at Kichijoji and it takes me 1 hour to get to work in Akasaka. I love my place and somehow get used to this routine, but honestly I wish I could rent a place in Japanese countryside.
If I could somehow guarantee a remote-work job for the foreesable future I'd love to move back and live somewhere more countryside but still with decent links to Tokyo such as the Shonan area or even somewhere a bit more east of Kichijoji like Hachioji or Ome.
I think this is the key thing. 75% of our family's problems would be solved if we could untangle ourselves from the burden of having to live in job-driven-metro areas close to the office. Mortgages would no longer be a problem, neither would school districts, neither would crushing commutes. Neither would childcare, since we'd have enough room in the house for help.
You can actually get a house for free in some areas, mostly central Japan.
Many cities are becoming deserted and houses are left alone, governments offer incentives to take them over. Might come with a catch such as committing to maintenance of farming.
The main catch is that the "free" houses are usually in complete disrepair and require a lot of non-free work to make them livable.
Building a new house in Japan is surprisingly affordable, but getting one built to Western standards (say, effective insulation and an expected lifespan of more than 20 years) is not. And I'm not even being facetious here: Japanese building codes assume that wooden houses last for 20 and concrete ones for thirty, then they get torn down and rebuilt by the next land owner.
My wife did a little light reading on this subject and found it's more complicated than that. It turns out that finding the owner of these properties is an enormous challenge because due to the high level of taxes and fees associated with these buildings, the owners are reluctant to claim them (to avoid paying the taxes/fees). I would like to see someone living in Japan confirm this, though.
I haven't seen any houses being offered for free in my area, but have seen number that were listed at less than $15K USD and wouldn't consider any of them livable without at least some major renovation - and in most cases you'd probably want to just demolish the house completely and build something new. Of course different people might have differing definitions of what is "livable", so your mileage may vary.
Focusing on the abandoned houses is a bit of a red herring, though. There is definitely affordable non-free housing to be found in Japan... less than $100K USD for a move-in ready house in a small city seems very doable to me.
