Any currency can be brought into Japan. However, if you carry more than 6,543,800 yen, or equivalent checks or securities, you must declare to the customs.
Foreign currency can be converted into Japanese yen at foreign exchange banks or other legal foreign exchange offices. At major international airports, there are also foreign currency exchange windows to provide currency exchange services for passengers. The exchange rate of RMB against Japanese yen is about 1: 14, but the foreign exchange rate changes with the fluctuation of foreign exchange market every day.