Gap is only a form of K-line, and K-line of every product may have a gap. As long as the lowest price of the latest K-line is higher than the highest price of the previous day, there will be an upward gap (high opening and high walking). Similarly, when the highest price of the latest K-line is lower than the lowest price of the previous day, a downward gap will be formed.

I don't know which market you mean by gold (paper gold, spot gold, TD gold, Shanghai gold futures in Shanghai, New Year gold in new york, etc.). ). Simply put, Shanghai gold is four hours a day, and the trend generally follows the New Year's gold, while the New Year's gold is 23 hours a day, so if the off-exchange market is very large, then the domestic trend will definitely follow the off-exchange market to open higher or lower the next day, causing a gap. More detailed, I hope I can help you.