In days of old Chinese traders used the “dotching”. On one side of the rod which is made of possibly fish bone hangs the pan with pointer/fulcrum and the weight (brass) hangs on the other side of the rod for counter balance. The rod is engraved with dots markings which are used as counters for weights. The 3 strings on the rod serve as balances.
Weighing an object requires putting it on the pan and the weight be moved along the long arm of the rod. At the place where the counterpoise keeps the rod exactly horizontal and the pointer/fulcrum aligned, the weight of the object is indicated on the engraved scale on the rod.
The Chinese “dotching” weighing scales are also known as “o-p-i-u-m” scales. They are a type of steelyard. The Chinese “dotching” originated in China and were first mentioned in western literature in the 17th century as “dotching” scales. They were used to weigh silver, gold, gems and medicinal powder/herbs.