The Dajinchuan Campaign lasted from the twelfth year of Qianlong's reign to the forty-first, with fighting breaking out on and off. The Qing court deployed nearly six hundred thousand men in total and spent seventy million taels of silver.
The Yuan dynasty was an age of paper currency. Though plenty of gold and silver were bestowed as rewards, salaries were mainly paid in paper notes. The Travels of Marco Polo recorded the process of forcibly requiring their use: "They were circulated throughout every province, territory, and land under the sovereign's rule. No subject, however high his station, dared refuse them, for refusal was punishable by death. I tell you, then, that everyone gladly used this currency, because wherever merchants went throughout the Great Khan's realm, they used these paper notes to pay expenses, purchase goods, and receive payment for what they sold, with no difference from pure gold. They were so light that notes worth ten gold coins weighed no more than a single coin."
Paper currency relied upon the sovereign's authority, but it also brought convenience to the sovereign. The Ming dynasty had once wished to issue Great Ming Paper Notes as the Yuan dynasty had, but it did not succeed.
The Qing dynasty also had silver notes, but they were issued by the Ministry of Revenue. After the White Lotus Sect uprising, transporting gold and silver across different regions became troublesome, and escort agencies could no longer deliver merchants' money home. Compared to the Two Huai salt merchants, whose vitality had been badly damaged by the salt certificate case, Shanxi merchants making money on the frontier had accumulated immeasurable wealth. They began heading south to establish draft banks, conducting exchange business that included official silver.
In the fifth month of Qianlong's fiftieth year, Qianlong was preparing to go