Profit retracement principle: Buy a currency, after buying, if you earn more than 10%, then we should start to implement the principle of capital protection (if it falls to the purchase price later, sell it immediately and unconditionally). If you earn about 20%, then you must make at least 10% profit before selling. In order to maximize profits, when you earn 20%, you must not sell it unless your profit falls to 10%, unless you have the technology to determine the stage high point, otherwise you will not sell it. Similarly, if you earn 30%, you must sell it unconditionally if it falls to 15%. This principle is that there is no technical judgment of the high point, and profit retracement helps you roll profits.