The quantitative easing policies of the United States and Europe have been introduced one after another. Japan has even introduced an unlimited amount of easing policy in the near future. China’s currency issuance even exceeds half of the world, and countries have successively entered a banknote printing competition. The first thing in this game is the worldwide devaluation of the currency, followed by the export battle on the trade battlefield. In particular, Japan has even publicly put trade protection on the table, and the international voice about global trade wars is growing. War is most like trade, war in war, equal to cash payments in trade. In peacetime, trade is also like war, and trade friction is just a tentative confrontation. Many people are far away from the trade battlefield and have not experienced it for themselves. Fundamentally speaking, the origin of the trade war is the currency exchange rate, and its core is the undervaluation of the local currency. In the trade market, which country likes its own currency depreciation. Anyone who has stayed in an export enterprise knows that even if the currency depreciates only a little, the export advantage will immediately tilt, and the country’s exports will increase immediately, and the effect will be very fast. If the local currency appreciates, the profits of exporting enterprises will be squeezed immediately, and the employees will be largely unemployed and exports will be reduced. If a large-scale trade war breaks out, the impact on the victorious country and the war-fighting country is enormous. The Japanese economy in the late 1980s was extremely inflated. In the eyes of many Japanese at the time, it was only a matter of time before Japan overtook the United States, and even surpassed the United States. At that time, Japan occupied a core position in all the cutting-edge industrial sectors in the West. There seems to be no one field that does not exceed its Western counterparts. Even US missiles are subject to Japanese technology.