Really incredible ancient Chinese coin error I just bought. As you may know, Chinese coins were cast since the beginning of their coinage ca 600 BC to the 1880’s AD. This is a fragment of a Wu Zhu mould ca 200 BC to 200 AD. Something happened when the bronze was being poured down the flue, and the semi-molten coin tree broke apart and fused with the mould. I had never seen anything like this, and probably will never see anything like it again!
Very cool mold fragment! Can you see the bronze on the other side of the mold as well? I'm not very familiar with the Chinese casting technique, did they pour into 2 casting holes at once, or is one of those plugged areas a vent/overflow hole? My first-impression is that the mold and/or the molten bronze was too cold when it was poured and it solidified before being able to fill out the intended coin tree. Considering that billions of coins must have been cast, what was usually done with all the used clay mold fragments? Landfill material? Infill for the Great Wall?
I don’t have the other side of the mould. I’d let you know if I did. Two halves of a mould had a single hole into which molten bronze was poured. When the bronze cooled, the moulds were broken away, and the coins were broken off the resulting tree. Then the edges were filed so that they were round and flat. The square holes were designed with this last step in mind. Then how did the metal escape the channels and then solidify in areas where the other half of the mould would be in direct contact? Many/most were thrown away after a single use to free the tree, though some were broken up simply to ensure that counterfeiters were not able to use them. What happened after that is anyones guess, but a huge hoard of clay Wu Zhu fragments was unearthed in Sanmanxia (sp?) city. Most/all of mine came from that hoard.
No lol, the bottom (other) side of your fragment is what I was curious about. Does the bronze continue to that side? Do either of those chunks of bronze represent the sprues from casting that continue to the other side, or are they only superficially adhered and representative of something else? So are you saying that the bronze present is what would be called "flashing" where metal routinely fills the narrow gap where the sections of the mold meet? It looked so thick that I thought they may have been sprues from initial pouring or maybe from overflow vents to ensure no air was trapped inside, not minor thin flashing which would fan-out evenly and not usually look like your item. If you've ever cast lead or bronze you may know what I'm referring to. Again I'm not very familiar with the Chinese production process so additional explanation regarding your very interesting numismatic artifact would be great!
Ah, ok. I don’t have that part either. No, I’m saying that what is seen here could not have happened during the normal minting process if the two sides of the mould were properly held together. Something happened (the thing binding the mould halves broke, the moulds themselves broke, etc.) and the semi-molten coin tree slipped out creating what is seen here.
