Currency Trading International

Why international trade requires a system for exchanging currency between nations?
Why not?
If you are a U.S. company and sell the rolls of paper in Japan for U.S. dollars, the Japanese buyer opens a letter from international credit on your behalf with your bank in the U.S. Once you send the reels, you ask for the dollar against the Japanese LC letters of instruction dispatch. The local bank that paid in U.S. dollars (Credits in your account) and the Japanese company is paying the equivalent in Japanese yen by bank dollar value for (Depending on exchange rate at the time of the transaction). What would you do as a society do with American Japanese yen? You can not pay their workforce here in America with the yen. This is how international trade. You are due to the exchange rate at the time of the transaction. This is usually done that way among all countries. As usual, the banks involved charging a nominal fee for paper work.
Trading International – Simple Moving Average