For centuries the Chinese use the Ching system of weighing objects.
There is a weight like in the photo below"
And this is how you balance the Chen to get an accurate measurement : the weight of the object will be noted on the notches as you move the ching tou or the weight. When the balance is reached (there is an arrow which indicates it) the reading on the notches will be the accurate measurement of the weight.
there is a Foochow saying related to the metal weight of the chen.
When a woman nags a great deal she is said to be a Hen pecking on a Ching Tou, the metal weight.
Gie moh bow ching tou.
No one wants to marry such a hen. She is also very unreasonable and silly.