Mother Coin 母錢 Virgin Hole! Qianlong Emperor 1768 Beijing Revenue Mint China
ANCIENT CHINA
Qing Dynasty
The Qianlong Emperor 
1768-1773 AD, Hartill 22.232
Beijing Board of Revenue Mint
Mother coin, 母錢



Authenticity guaranteed for all items!
Reference: Hartill 22.232
Weight: 5 grams; Size: 25.3 mm; Fine Brass
Obv: Qiang Long Tong Bao
Rev: Bao Quan (The board of Revenue Mint)
 
“Mother Coins 母錢” in old Chinese coin making
During the Han Dynasty, Chinese mints partially solved the inconsistencies in cast coins by using bronze master moulds. Master moulds were used to prepare the clay moulds which will be used for the actual casting.

Advances in the casting process in the sixth century resulted in the introduction mother coins (mu qian). Mother coins were used to impress the designs of the coin on very fine wet sand that would act as moulds for the coins. A mother coin was prepared by carefully engraving a pattern of the coin in a material that can be easily worked with such as tin.

The coin casting process involves the use of a rectangular frame filled with fine wet sand, presumably mixed with clay, and sprinkled with charcoal or coal dust. The dust allows the molten metal to flow smoothly. It also acts as a layer that separates the two halves of the moulds.
Mother coins are pressed on the wet sand in the wooden frame (first half of the mould). Rods are placed between the coins to create channels where the molten metal can flow. A second frame (second half of the mould) is placed on top and pressed tightly. This imprints the designs of the obverse and reverse of the mother coins on the sand in the frames.

The mother coins are then removed and transferred on top of the second frame to create new moulds. This processed is repeated until up to fifteen layers of moulds are created. The wooden frames are bound tautly and filled with molten metal, usually bronze.

This process creates a “coin tree,” cast coins connected by hardened metal on the channels. After brushing off the sand, coins are broken of the “tree.”

To make the edges smooth, the coins are strung together on a long square rod and the coin edges are filed down. It is further polished in tubs of chaff or sand before the final stringing.

The use of mother coins proved to be effective in controlling the quality of the coins. Slight differences between mother coins still existed however skillful the carver is.
 
 
The Qianlong Emperor 1735 – 1796 AD
The Qianlong Emperor (25 September 1711 – 7 February 1799), formerly romanized as the Chien-lung Emperor, was the sixth emperor of the Manchu-led Qing Dynasty, and the fourth Qing emperor to rule over China proper. Born as Hongli (formerly Hung-li), the fourth son of the Yongzheng Emperor, he reigned officially from 11 October 1735 to 8 February 1796.1 On 8 February, he abdicated in favor of his son, the Jiaqing Emperor – a filial act in order not to reign longer than his grandfather, the illustrious Kangxi Emperor.[1] Despite his retirement, however, he retained ultimate power until his death in 1799. Although his early years saw the continuation of an era of prosperity in China, his final years saw troubles at home and abroad converge on the Qing Empire.
 
 
 
 
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