The calculated exchange rate is based on the real-time exchange rate on the international exchange rate website on February 2, 2020.
The safest and most common way to travel from China to Japan is to exchange local currency.
Prepare enough yen before you travel, so you don't have to worry about changing foreign exchange after you go to Japan.
If you run out of Japanese yen during your trip, you can also get cash locally through ATM or bank remittance service.