KDJ's technical indicators are really powerful when analyzing, but it should be noted that there should be differences between large-cap stocks and individual stocks, so that we can use KDJ to analyze large-cap stocks and select good stocks. Conditions: KDJ index parameter is 9; Used for market judgment; Can only be used for weekly K-line charts.

Judgment: when the J line of KDJ indicator is negative to+10, buy; When the J-line of the KDJ indicator falls from 100 to below 90, it is sold. This method can basically grasp the top and bottom of the market, and the accuracy is quite high. However, not every market can be caught. Sometimes, the J-line of KDJ turns around and rises without falling back to a negative value, or falls back when it can't rise above 100, which may miss some markets.

Theoretically, KDJ is a short-term indicator, especially J-line is more sensitive than K-line and D-line, but it is very sensitive to the center line when applied to weekly K-line. Sensitivity and stability can be taken into account, so it is feasible in theory. However, it should be noted that: 1. When the J-line reaches above 100 or reaches a negative value, the market reaches a relatively extreme situation. Therefore, when the market is not in an extreme state, it is possible to miss some quotes. Second, this method is more accurate for the market, but when it is used for individual stocks, the situation is quite different. Different stocks have different stock characteristics, and profitability depends on the effect of stock selection.