Holy moley! I remember a time when there weren't known to be any Mini Travellers surviving in the UK, never mind in Japan!
I *just* recall my granny having one in her barn, though I don't recall her ever driving it. Probably a good thing as she was of an age where she started driving before the driving test came in - Dad always claimed he'd once followed her carefully driving down the white lines in the middle of the road, and she couldn't handle the dip switch on the floor so her passenger had to operate it for her!