a mother coin among Chinese Cash

[samwyi]

Since Chinese Cash are produced by sand-casting after Song Dynasty(or earlier),  you may occasionaly find some "mother piece" among you collections. They were used to create molds. Qing dynasty mother pieces are typically casted with refined materials and high relief and hence have great eye appealing appearance. You can think them as Proof coins. Here is a typical example:

[Howard Cole]

No.  You can not call them proof coins.  A proof coin is made in a special process.  The blank is highly polished.  The dies are usually fresh dies with all the details very sharp.  An finally the blank is double struck (without shifting the axis).  Proof coins, I think, are a fairly modern invention.  They have only been made since machanical striking of coins started.

As for cast coins, the Chinese have been doing this since they invented coins.  Seed coins are made in special molds and have sharp detail as you stated.  They are used to make molds for the production coins.

[samwyi]

yes, hcole_1989 gave a much clear comment.

[tenorhans]

It is really very very nice!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

Generally, and with a little lucky  ,you can get one piece in almost 100 kilogram common coins

[yide]

sharp detail ......  it is not mine