Qianlong Tongbao (traditional Chinese: 乾隆通寶; simplified Chinese: 乾隆通宝; pinyin: qián lóng tōng bǎo; Vietnamese: Càn Long Thông Bảo) is an inscription used on cash coins produced under the reign of the Qianlong Emperor of the Qing dynasty.

Initially the Qianlong Tongbao cash coins were equal to its predecessors in their weight and quality but as expensive military expenditures such as the Ten Great Campaigns began to take their financial toll on the government of the Qing dynasty the quality of these cash coins started to steadily decrease.

The weight of the Qianlong Tongbao was changed several times and tin was added to their alloy to both reduce costs and to prevent people from melting down the coins to make utensils.

A special characteristic of some Qianlong Tongbao cash coins is that the Chinese character "Long" (隆) at the bottom is sometimes written with a "Fou" (缶) instead of the usual "Sheng" (生).

These Han employees from Shaanxi also brought 2 full sets of both casting and melting equipment with them to aid production.

[4] The Western cities of the Southern Circuit were poor in natural copper sources and required the reclamation of pūl coins for the production of cash coins while in the Eastern cities of the Southern Circuit such as Aksu, Karashar, Kucha, and Turpan copper was more easily acquired as this area was rich in copper ore. Because of this the government of the Qing dynasty opened a massive mint with six furnaces and employing 360 workers in the city of Aksu in the year 1761, among its employees were technicians sent to oversee the coin production brought in from the mints of the Gansu and Shaanxi provinces.

After a Muslim uprising against Qing rule occurred in the year 1765 the Qianlong Emperor decreed that a large number of soldiers should go to Turfan.

These regions also saw an influx of immigrants from China proper who brought with them their own money and in the Eastern Circuit the local population had already adopted the Chinese monetary culture prior to its conquest by the Qing dynasty so these two circuits would use the same type of cash coins as were used in China proper and did not have to adopt a completely different monetary system.

Generally the cash produced by the Yining Mint were of the same weight and size as found in the rest of China and also used the same alloys, but the copper content of Yining cash coins was occasionally higher and the weight of these coins often exceeded the national standard and could weigh more than 5 grams.

The Chinese characters of this amulet are also different style from those of circulating Qianlong Tongbao cash coins, such as the bottom part of the "Bao" (寶) and the radical portion of the "Tong" (通).

[15][16] According to Mr. Zhou Qian (周乾), a researcher at the Palace Museum, the Qianlong Tongbao coin dragon could be described as "About 2 meters long, mighty and shocking with fierce teeth and dancing claws, creating clouds and driving the mist" (该钱龙长约2米，张牙舞爪，做腾云驾雾状，形象威武，极具震慑感。).

[15][16] As no known historical documents recorded the existence of this coin dragon it is possible that it was in fact meant to remain a secret hidden away from sight.

[15][16] The coin dragon was likely installed during a Shang Liang (traditional Chinese: 上樑; simplified Chinese: 上梁; pinyin: Shàng liáng) ceremony, this is evident of the remnants of the red silk satin from this topping-out ceremony which occurred several centuries ago.

[15][16] During these ceremonies Good luck charms, which frequently included cash coins, would traditionally be attached to one of the palace's roof beams in order to provide protection from evil spirits, fire, and other potential disasters.

[15][16] The coin dragon thus serves as the supreme representation of the Chinese belief in numismatic charms as objects with supernatural powers which are able to defeat ghosts and demons, deter disastrous events, and bring both peace and good luck to those in possession of them.

[17] These armies would easily defeat the Tây Sơn dynasty at several battles and took Thăng Long (modern Hanoi) on November 19, 1788, reinstating Emperor Lê Chiêu Thống (黎昭統).

[17] After the forces of the Quang Trung Emperor (光中帝) retook Hanoi and expelled the Chinese and Revival Lê forces back over the Chinese border the Viceroy of Yungui, Fu Gangan (富綱安) was chosen to head the army and marched back into Vietnam and concluded a truce recognising the revolutionary government.

[17] During this episode special Qianlong Tongbao cash coins were cast in the province of Yunnan as payment for the Chinese troops who engaged in this invasion which featured the characters "安南" (The Pacified South) on their reverse.