There are three main sources.

1, Mexico, silver was produced in the Spanish colony of Mexico at that time. The trade between China and Mexico mainly transits through Manila. 1565, san pablo returned to America from the Philippines, thus opening a round-trip route between Mexico and the Philippines. 1574 (the second year of Wanli), two Manila merchant ships were loaded with goods from China and sailed for Acapulco, marking the official operation of the famous Manila merchant trade. In this way, the Spanish shipped goods to China (including raw silk, silk, velvet, silk, satin, cotton cloth, linen, jewelry, handicrafts, tin-lead products for steel, saltpeter, gunpowder, food, poultry, livestock and so on. , especially textiles) to America, and then import silver to China. Due to the huge demand in the Spanish-American market, China's silk and cotton products quickly jumped to the top of Manila galleon's exports to the United States, and remained until the end of galleon trade. Transport silver to China. Because it is difficult for European goods to compete with China's cheap goods, the Spanish, Portuguese, Dutch and British who later entered the trade with China had to buy goods from China with coins, and the huge foreign trade surplus remained until the eve of the opium trade in19th century. The silver flowing from Spanish America to Manila was about 6,543,800 pesos per year at first, and then it reached 2-3 million pesos, and sometimes even exceeded 4 million pesos. During the period of1571-1821,American silver was imported into Manila as much as 400 million pesos, most of which (also said to be 1/2 and 1/4) were exported to China. It is estimated by foreign scholars that 1/3- 1/2 of the total silver production in the United States has flowed into China. In a short period of 163 1 year, the silver imported from the Philippines to Macau reached14 million, which was about 2./kloc-of the total output of China's official silver mines in the heyday of the thirty years from the first year of Yongle in the Ming Dynasty to the ninth year of Xuande (1403- 1434).

2. Japan, Japan not only buys goods from China with silver, but also exchanges money from China for coins. Japanese silver flowed into China earlier than American silver, and there are two ways of inflow: private smuggling trade and Portuguese entrepot trade. In the Ming Dynasty, Sino-Japanese relations were far from warm. Japan's frequent invasion and Toyotomi Hideyoshi's invasion of North Korea caused the relationship between the two countries to fall to freezing point, so the Ming Dynasty suspended its trade with Japan as a severe ban, and Japan was still excluded when the sea ban was reopened in the first year of Qin Long. However, the profit-seeking nature of businessmen eventually made this kind of sanctions largely a dead letter, and smuggling trade was repeatedly banned, becoming the main form of direct trade between China and Japan. During the Jiajing period before the Spanish conquered the Philippines, while the demand for silver in China was increasing, the smuggling trade between China and Japan made a large amount of Japanese silver flow into China. However, the direct trade between China and Japan was greatly restricted by the ban of the Ming Dynasty. The Portuguese had good relations with the Ming court and celebrities along the coast of Japan, and took advantage of the preferential treatment given by China and Japan to play a greater role in Sino-Japanese trade. In the thirty-second year of Jiajing (1553), the Portuguese took the initiative to attract Japanese to trade in Guangdong, and finally established a Portuguese-Japanese trade network centered on Macau and Nagasaki. China scholars estimate that during the last 25 years of the16th century, half of the silver produced in Japan flowed out, most of which were transported away by Portuguese businessmen, with an annual amount of 500,000-600,000; By the first 30 years of the17th century, the annual shipment exceeded1000 billion taels, sometimes as high as 2-3 million taels. /kloc-At the beginning of the 0/7th century, Portuguese historians estimated that the value of silver exported by Portuguese galleons from Japan each year exceeded/kloc-0.00 million gold coins. According to a survey by Noi Shiraishi, a Japanese scholar, during the 47 years from 6 years of Qing Dynasty to 4 years of Bao Zheng (that is, from 29 years of Wanli in Ming Dynasty to 4 years of Shunzhi in Qing Dynasty, Gregorian calendar1601647), the total output of Japanese silver reached more than 74.8 million, and most of it was imported into China. The massive outflow of Japanese silver from China made the Japanese government uneasy. In order to reduce the outflow of silver, the Japanese government issued decrees in 1689 and 17 15 to restrict the quantity and trade volume of Japanese merchant ships to China.

However, silver flows into China not only through trade, but also through the arbitrage business carried out by Europeans between China, Japan and Europe. During the 16 and 17 centuries, there was a great price difference between gold and silver in China, Japan and Europe. The price difference between gold and silver in China is 1: 5.5-7, that in Japan is 1: 12- 13, and that in Europe is 1.