Yang covering yin refers to a K-line combination in which after the stock price has fallen for a period of time, a middle or large yang line suddenly appears and engulfs all the yin line of the previous day. This shows that the bulls exerted their strength and defeated the bears in one fell swoop, causing the trend to reverse. Investors often view this combination as a signal for rising stock prices. The changing form is that the negative line in the front does not necessarily have to be just one, but can also be several, as long as the positive line in the back engulfs them all. As a buying signal, yang and yin need to be comprehensively studied and judged based on its appearance position, trading volume, etc.