There are two kinds of necklines (after rising and after falling). In a wave of rising market, after the stock price (or index) reaches a certain height, it retreats to a certain point to stop falling, rises to the previous high point again, and then falls again, effectively breaking through the low point in the previous retracement process. The line extending from the low point to both ends is the neckline, which can be horizontal or inclined;

The above is the rising neckline, and the falling neckline is the opposite of the rising neckline.