Here are all explain
History of
chinese casting coins is not easy, I don't have all necessary knowledge to be
complete but I can resume it. I can't give you any date because many system where used simultaneously...
Originaly, the coins where casted in Sand or clay mould, such moulds where easy to make but they where easyly broken when people tryed to take the casting
money or during cooking.
For this reason, they did look to make moulds with higher resistance. They did use soapstone(1) but such moulds where too heavy so the system can
still be better.
Sometimes later, they did find 1 others systems, who give us 2 possibility of developpement:
First, they did make a mould to make mother mould so they did
engraved (about 50 cavities) in
stone (2) in the capital and they did
cast clay in. So maked mother mould. These mother mould where exported in others city and
mint. The workers in those mints did
cast bronze and maked bronze moulds. The bronze mould
had advantage than they was reusable for same coin like to make others moulds and the mother mould in clay where easy to broke if anybody want to steal it. The only problem was than such mother mould where fragile and where often broke on the way between making and
mint.
Second, they did make a mould to make mother mould so they did
engraved (4-10 cavities) in
stone (2) in the capital and they did
cast bronze in. So they maked mother mould. These mother mould where exported in others city and
mint. Like such mother mould where small, it was easy to hide again thief. The workers in those mints did press this mother mould again clay. The small clay plates such making where staked to make overlap moulds in which they did
cast bronze coins.
Many years later they did used Mother coins (First I know
comes from Ming dynasty(1368-1644 AD). the Mother coins can be of 1st or 2nd generation, they are easy to identifi because the 1st generation mother moulds have round hole and deepest
writing than for 2nd generation. The secong generation mother coins have square hole and deepest
writing than coins.
I will post here all moulds from my
collection and give illustration of all different moulds, mother moulds and mother coins quoted so it will be more easy to undestrand.
(1) Soapstone have
good thermal resistance and is realy easy for engraving.
(2) Such itme are
still undiscovered, this theory
comes from Francois
Thierry de Crussol a great world class expert.