What do you mean by burying the mountain gate?

Burying the mountain gate is a sacrificial activity.

According to the ancestral system, there is a certain time limit for sacrificial activities. Three days before Tomb-Sweeping Day, the gate was wide open to receive people who came to sacrifice, and Tomb-Sweeping Day continued to receive them five days later. A total of eight days, after eight days, the mountain gate closed, the sacrificial activities ended and returned to normal.