There are still plenty of stores in Japan that do not accept credit card payments, compared to other countries.
Always bring cash with you when eating out or shopping at small shops.
The most readily accessible option for exchanging into Japanese yen are the ATMs located in major convenience stores such as 7-Eleven and Lawson.
These convenience stores are available in most cities and train stations.
Rest assured that you can use these terminals without any problems as multi-language support is enabled whenever a card issued overseas is inserted into them.
【Support】Withdrawing in Japanese yen
Banks and post offices provide foreign exchange services in both Japanese yen and foreign currencies.
Officially supported cards may vary from bank to bank. When in doubt, please check with the bank you are transacting with.
Stores that accept credit cards will have a sign that says "カード利用可能" (credit cards welcome), along with the logos of the cards they accept. Please check for this sign when transacting with the store.
Your signature and/or PIN may be required when making a purchase, just like it would anywhere else in the world.
In general, cards issued overseas may be used in Japan but note that some cards may be unavailable for use.