The main problem in Japan is that most of the cash machines don’t accept
any western cards, and a lot of shops/hotels/businesses like to deal in
cash. The ATMs in 7/11 shops or post offices are usually pretty reliable,
but get out plenty of cash when you find one. Revolut has no transaction
fee until you go over whatever the monthly limit is at the moment
(£500?),but even with fees it was better rates than my traveling
companions.