Below are four key points that users should understand about the opium trade in the 1830s in order to contextualize the information in this module.

1. Opium's legality: The sale and consumption of opium was extraordinarily widespread in China during the 1830, but it was entirely illegal. This meant that all of the opium sold and consumed in the Qing empire during these years had to be smuggled in and distributed illegally. As a consequence, there were infinite opportunities for corruption and government participation in the illegal trade, from the moment of import, at each node in the distribution network, down to the retail and smoking of the drug.

2. Opium trading practices: The opium sold in China in the 1830s was grown in India and smuggled into the Pearl River Delta near Guangzhou (Canton) by primarily British merchants. Americans and various British colonial subjects (especially the Parsee community of Bombay) were also involved in the transport trade from India to China.

Since at least the mid-1820s, the central location for opium transactions between foreign and Chinese merchants was an anchorage off the island of Lintin in the Pearl River Delta near present-day Hong Kong. At this remote offshore island, British firms permanently anchored large "receiving ships," which were stationary vessels that operated as floating warehouses. Chinese buyers would go to money-lending shops in Guangzhou (Canton) to make payment, then take a receipt out to a foreign receiving ship anchored near Lintin to receive their opium. In this way the British and Chinese merchants involved in the trade could keep their transactions out of the immediate surveillance of the high officials in Guangzhou.

3. Opium's northward migration: The Lintin system of offshore opium transactions expanded north from Guangdong province into neighboring Fujian province around 1834, when British firms established receiving ship stations in various locations along the southern Fujian littoral. This migration of the trade from the Pearl River Delta north into Fujianese ports like Xiamen and Shenhu Bay is the primary subject of this module. The timing of the trade's migration in 1834 is due to the British East India Company relinquishing their monopoly over British trade in China that year, which opened the door for new British firms like Jardine-Matheson and their competitor Dent & Co. to expand the trade into new markets.

4. The aftermath: The events of this module take place in the years just before the Opium War of 1839-1842. That war began in the wake of an incident wherein a Qing official named Lin Zexu determined to confiscate and destroy the opium holdings of Jardine-Matheson and a number of other firms. William Jardine spent the duration of that war in London lobbying the British Government to secure compensation for the opium that Lin destroyed.

There are numerous important consequences of that war that users are encouraged to investigate outside of this module, but here I wish to draw a connection between this module and the Opium War in order to help users understand where the sources here fit in. As discussed in point three above, this module is concerned with the migration of the Lintin System into the province of Fujian, where Jardine-Matheson and their Chinese partners established a hugely successful opium import market. For anti-opium officials like Lin Zexu (himself a native of Fujian), one of the unforgivable actions of the opium traders was in moving their boats up the coast from the Pearl River Delta, which had an established system of legal trade for Europeans, and anchoring instead in Fujian, where foreigners from Europe were not allowed to travel.