Nanjing forging industry of gold foil originated in the area around Longtan Garden in Qixia District, which once belonged to Jurong County and Jiangning County. In all rural families of this area, the handcraft of "forging foils and producing threads" has been passed down from generation to generation. Forging techniques of gold foil refers to the skills of forging gold into thin foils. The gold foil is often used to decorate Buddha Statues or utensils. Featured by unique techniques of high standards, production of gold foil in Jinling has remained a special type of traditional handcraft throughout Chinese history.
Gold foil of China derived from Nanjing, and that of Nanjing from Longtan. According to the existing data, with a history of over 1600 years, gold-foil techniques of Nanjing in Jiangsu Province originated in the Eastern Jin Dynasty. As early as in the documents from the Southern Dynasty, there were already records about production of gold and silver foil, as well as about the establishment of a brocade office. Mass-production of gold foil started in the Yuan Dynasty, which was further developed in the Ming and Qing Dynasties. Outside Taiping Gate in 1975, official robes embroidered with gold threads were unearthed from the tomb of Xu Fu, the fifth generation of Xu Da's descendants. The robes serve as material evidence of spun gold in Jinling over 400 years ago. As introduced by aged craftsmen, it was Longtan people who first started to forge gold foil in Nanjing. Originally, there were three clans engaged in this industry, respectively surnamed Liu, Ge and Yin. While Liu clan forged gold foil, Ge clan cut gold foil, and Yin clan made gold threads.
In places like Longtan and Jiangning in Nanjing, over ten procedures passed down from ancient times are still adopted in the current production of gold foil. Specifically, the procedures include calcining and melting the gold bullion, forcefully beating the bullion into a thin gold leaf, cutting the leaf into smaller leaves, further hammering gold leaves enfolded with black-golden paper, taking the leaves out of the paper, cutting them into foils, and checking on the package. It is the most demanding to beat the gold bullion into foils, in the process of which the bullion has to be hammered into foils as thin as 0.1 micron. Face to face, a pair of workers has to beat the bullion tens of thousands of times before fulfilling the task. Nanjing gold foils, made through forging, are as thin as the wing of a cicada, and as soft as silk. According to the folklore, gold foil forged out of a liang (equal to 50 grams) of gold can cover 1.3 mu (1 mu equals 1/6 acre) of land. Meanwhile, according to scientific calculation, 943 gold foils altogether are no thicker than one millimeter, and ten thousand foils weigh no more than 178.125 grams. Accordingly, gold-foil forging truly boasts exquisite techniques.
In contrast to the gold foil, the gold thread is no more than an additional product. However, it requires techniques which are not only far more complicated than those of the gold foil but also on the verge of extinction. Stick the gold foil to a special piece of paper. Polish it with Yuhua stones (a special kind of stone in Nanjing) and agates. Cut the foil into threads, and then twist them into circular gold threads. There are altogether twelve procedures from paper and powder making to the completion of the gold thread. The gold foil is finally twisted into thin yarns with a diameter less than one millimeter. Usually in a week, a craftsman can only produce gold threads as long as a couple of or tens of meters. Afterwards, weaving girls will make clothes which are embroidered with the gold threads.
