The reason is to watch the time, give orders, and be wary of your own practices. So the monk had to ring the bell. The word "historical bell" has long existed. In other words, it should be called a long history. For example, in The Book of Rites, compiled by Dai Sheng, a ritual scholar in the Western Han Dynasty, it is written that being kind to questioners is like ringing a bell. Those who knock small are loud, while those who knock big are loud.

Bells, Chinese words, a temple fair.