If it crosses at a high level, it is a dead cross and you need to sell the stock; if it crosses at the bottom, it is a golden cross and you can buy the stock.

KDJ stochastic indicator judgment principles:

1. Generally speaking, when the D line turns from bottom to top, it is a buy signal, and when the D line turns from top to bottom, it is a sell signal.

2. KD fluctuates in the range of 0 to 100, and 50 is the long-short equilibrium line. If you are in a long market, 50 is the support line for retracement; if you are in a short market, 50 is the pressure line for rebound.

3. When the K line crosses the D line at a low level, it is a buy signal, and when the K line crosses the D line at a high level, it is a sell signal.

4. When the K line goes above 90, it is an overbought zone, and when it goes below 10, it is an oversold zone; when the D line goes above 80, it is an overbought zone, and when it goes below 20, it is an oversold zone. It is advisable to pay attention to the timing of buying and selling.

5. The M-shaped trend of the D line in the high-end area is a common top form. When the second head appears and when the K line crosses the D line for the second time, it is a sell signal. The W-shaped trend of the D line in the low-end zone is a common bottom form. When the second bottom appears and when the K line crosses the D line for the second time, it is a buy signal. If it deviates from the price trend, it is called "top divergence" and "top divergence" respectively. "Bottom divergence", the buying and selling signal has extremely high credibility.

6. The J value can be greater than 100 or less than 0. The J indicator value provides a credible judgment on whether action can be taken based on the KD buying and selling signal. Usually, when the J value is greater than 10.

7. KDJ is essentially a random fluctuation indicator, so the N value in the calculation formula is usually small, preferably 5 to 14, and can be selected according to the characteristics of the market or product. However, applying KDJ to weekly or monthly charts can also be used as a tool for mid- and long-term predictions.