I apologise that my post doesn't directly answer your question but, while researching it, I've come across some information which might be useful to you, so I thought that I'd post anyway.
It seems that you might need to keep an eye open for 7/11 convenience stores, which look like this:
http://3.bp.blogspot.com/_UKpamHGACkM/TU_lC-nUMCI/AAAAAAAAAIE/wk8my1aNGE0/s1600/japan-711-convenience-store.jpg
That's based upon reading this, on the official website of the Japanese tourist authority:
"Japan is largely a cash based society, so you can expect to pay in cash at most restaurants. Carrying large amounts of cash is commonplace; something the level of safety in Japan allows.
When you want to withdraw money, you can use your debit or credit card at cash machines inside 7/11 convenience stores, which are located all over Japan, even in the countryside. Japanese banks and other convenience stores do not widely accept withdrawals using overseas cards."
(Source:
https://www.seejapan.co.uk/plan-your-trip/practical-information )
That's confirmed on Wikitravel, which provides a great deal more relevant information:
https://wikitravel.org/en/Japan#Buy
(Scroll down to the paragraph beginning "Japanese ATMs generally do
not accept foreign cards . . . " and read on from there).
Hoping that helps (a bit, anyway)!