Since Japan is a cash bassed society, you might find it difiicult to make mayment bycredit card in some locations. Whille local banks and post offices offer a currency excange serivices, rate are often not so great.
Also, you will be having a lot of issues communicating with those who work in local banks and post offices.
We here have a fluent English speaker with very gentle rate for excahging curency.
Not only we handle money exchange, we will give you informations about the city if you need an assistance.