The reason may be that there is important news in China on the same day or overnight in the external market. Some people predict that the day will definitely plummet or even fall, so some of these people will choose to stop at the opening. In addition, there are too many people who are worried about stop loss, and their orders will not be flat. So when I was in call auction, I chose the price limit report.
Accordingly, some people estimate that the market sentiment is too pessimistic. Although cotton will open lower, it will not fall below the limit. Then someone will hang more than one order on the daily limit, which is equivalent to bargain hunting.
When these two situations happen at the same time, in call auction before the opening, someone will close the transaction at a price limit and become the opening price. This is the picture you sent.
In fact, when the market fluctuates greatly and the news is unstable, people often hit the daily limit, but rarely. Others hit the daily limit and price limit until the final transaction.
You can compare the time-sharing chart of the day with the daily K-line. On the time-sharing diagram, the starting position of this line starts from about 2 1200. The price limit of 20490 does not see any transaction or volume. Thirdly, this price occurred in the process of call auction and became the opening price.
So, to answer your question:
1, the explanation of how the price occurs is as above. This has nothing to do with whether it is huge or not, because it won't bounce back after falling off the plate.
2. When you say "stop loss", there are actually many situations. There is no stop loss setting in ordinary software, and the stop loss setting in high-end software is conditional. It depends on your meaning. Below 2 12 13 is the stop loss. Then it's basically a limit stop loss. After the gap, as long as the price is lower than 2 12 13, the system will automatically declare your position at the market price.
China has no overnight stop loss.
3. Yes, but it is not the so-called "intraday fluctuation", because this happens at the opening.
4. This is not a shadow line.