What do you mean by fast and heavy in ancient knocking etiquette?

First, we should dig. Knocking again is not only reckless, but also disrespectful to others.

When knocking at the door, knock two or three times and pause for a while to see if anyone answers the door; You can't knock any more, but don't keep knocking.

If there is no response when knocking at the door, you can ask, "Is so-and-so at home?"

If the door is unlocked or open, don't open the door to watch or go straight in. You should knock on the door several times to get in. If there is a doorbell at the door, don't press it.

When knocking at the door, the first thing that comes to mind is politeness. If an elder opens the door for you, you should also say "thank you".