In China, (back in the day.....)many tools were traded such as knives and ploughs, and in particular the shovel became a popular barter object. A rich man had a whole row of shovels on his land which were, in fact, not used to work the land but served purely as a means of trade. Smithies made additional shovels which became progressively smaller: these were not handy for digging, but extremely handy for bartering. At a given moment, the shovels had become as small as a present-day coin. Then finally somebody came up with the idea of making them round. The abstraction was complete. What you have is a coin that commemorates (by its image) the Chinese shovel used in the historical bartering system.
Your coin's educational and historic value far exceeds its numismatic value.
Don.........