The official currency of Japan is the yen.
Bank counters at Narita Airport offer foreign exchange services to convert major currencies (cash or travelers' checks) into yen. You can withdraw cash from ATM machines located in Narita Airport using cash cards with the PLUS or CIRRUS symbol.
The 77 Bank has a counter on the ground floor of the Sendai Airport terminal building, where a foreign exchange service is available. Banks and post offices in Sendai also provide the same service, but some currencies may not be accepted. Please note that bank counters are open only on weekdays and close at 3:00 p.m.
Seven-Eleven convenience stores and post offices operate ATM machines that accept cash cards issued by foreign banks. Both have an extensive network throughout Japan, and their ATMs provide English guidance. The service hours of ATMs at post offices are limited, depending on the location. Seven-Eleven stores offer 24-hour service.
"Credit purchase" is popular here in Japan, but some, mostly small, restaurants and shops may not accept credit cards. Credit cards can also generally not be used to purchase tickets for public transportation or at other public facilities. Always bring cash with you for shopping and dining, just in case. Shops and restaurants generally do not accept checks.