K line is also called yin-yang line, bar line, red and black line or candle line. After a period of trading, the stock price forms a special region or form on the chart, and different forms show different meanings. K-line chart originated from Tokugawa shogunate era in Japan. It was used by businessmen in Japanese rice market at that time to record the market and price fluctuation of rice market, and then it was introduced into stock market and futures market because of its ingenious and unique drawing method. [1] Through the K-line chart, you can completely record the market situation every day or for a certain period of time. The three K-line combinations of insertion line, holding line and favorable stimulation line are the most common classic bottoming forms.