Hi. We're a recently retired couple in early 60's down in Australia. We've been to Japan many times and I lived there when I was a kid for a couple years and worked there in the early 70's (aviation). I speak some Japanese - but not fluent. We go there every year or two, because we love it - great people, and it is a lot cheaper, more beautiful, and safer than most outside Japan think. My wife speaks basic Japanese, and she is from an Asian background. I love driving there and we do get around, been everywhere from Okinawa to northern Hokkaido.
My question is. We don't intend to live there forever, but we would like to spend several years with regular periods of living there. To that effect, I wouldn't mind buying a traditional house out in the rural/small town areas. I know we can do it cheaply. I'm estimating 50-100K USD at very most - but perhaps less. Just do the essential upgrades - kitchen - bathroom. A/C and/or heating if needed - and whatever repairs it needs to be water and weather tight. Nice old wood structure with wood/tatami floors - we AirBNB and love the lifestyle. We've got an open mind on location for now - anything from Yaeyama islands to outside Hakodate would suit us fine for various reasons. Currently we are thinking Noto, or Maizuru area, or small town out of Kyoto. No need to work - we have our retirement pensions and they are adequate to live well enough. And we don't mind living amongst the Japanese only...love the food, love the people, love the beauty of the entire country. We'll be fine. My wife speaks several languages, and I speak a few so we'd both be fairly fluent in Japanese within a few months.
That said, as far as I know we can only get 90 day visas. That's fine...we can bugger off to Korea or Taiwan for a couple days and then come back....but can we get another 90 day visa when we return? That is the question. I haven't seen anything clear on that - and I read somewhere a few years ago that it was solely the discretion of the immigration officer. I would imagine we would want to come and go for at most three successive 90 day visas (with a couple days somewhere else in between), before we do a few months in Australia - and then return to Japan for more fun - and a series of more 90 day visas. Is that possible? Or is it too hard? And if we buy a house, how hard is it to get electricity, telephone, etc considering we are not residents - but happy to pay a deposit to cover our costs for months in advance.  Just wondering. Haven't seen anyone quite in the same position - I do indirectly know of an old Australian in Niseko who has a house that goes there often, I know via his niece, but he goes there once or twice or year - but never in and out. Comes back to Oz for several months and then goes up to Hokkaido again. We are of the mind of doing 6-9 months at a time, using 'our house' as a base for our in-depth exploration of Japan. Which brings up another question - can I buy a car there? Rental cars - small ones - are almost reasonable. But buying a used larger one would be very handy.
That's the story - mainly a question about visas - leaving Japan for a couple days and coming back.....Arigato ne..