Originally called Hwasung ("Brilliant Castle"), Suwon Castle was completed in 1796 after over two years of construction on the orders of King Chongjo, the 22nd monarch of the Choson dynasty, in memory of his father, the crown prince Sadoseja. Sadoseja, a victim of court intrigues and factional feuds, was starved to death in a locked wooden rice storage box. Thus, Suwon castle is a symbol of filial piety and political reform.
The practical and utilitarian wisdom of sirhak (“pragmatic studies”) scholars in the 18th century were manifested in the innovative and scientific construction methods employed in building the fortress. Modern equipment such as a mechanical crane and pulleys and a new method of baking bricks were developed and used in erecting the walls of Suwon Castle, which were built in a unique style never found in China and Japan with both defense as well as political and commercial functions in mind.
Chong Yag-yong was outstanding among the scholars who analyzed the evils of society and made positive proposals for reform. He saw the paramount importance of agriculture, stock-raising, fisheries, and sericulture. He advocated a system of land distribution based on egalitarian principles, and the placement of people in professions in accordance with their ability.
Exploitation continued, however, and distressed people sought salvation. Catholicism met the needs of many, since its tenets accorded with the new egalitarian principles in addition to stressing salvation. Some scholars were converted to Catholicism, and others benefitted from the scientific learning that accompanied the religion. The number of Catholics in Korea gradually ncreased.
Since Catholicism was opposed both to Confucian ancestral rituals and to rigid social stratification, Catholics were termed criminals by the state. Many of them, including prominent scholars such as Chong Yag-yong and his brothers, were punished or even executed.
Meanwhile, partly because of the stimulus of Western ideas, a new school of thought was growing up among the Korean intelligentsia. Called Sirhak(Practical Learning) it was directed primarily against the preoccupation among the bureaucrats either with Chinese literature or with the speculative side of Chu Hsi’s neo-Confucianism. The Sirhak scholars demanded an end to empty formalism and concern with ritual trivialities and a return to the true spirit of Confucianism. They also demanded a practical, empirical approach both to government and to learning. The movement had its roots in the 17th century, but came to prominence in the 18th.
Chöng Yak-yong (1762-1836) added to these elements of Sirhak thought the stimulus of Western learning. He eagerly studied all the Western books he could obtain and, in addition, became a believer in Catholicism, for which belief he was banished in 1801 to a remote island where he remained for 18 years. During his exile he worked out in detail his ideas for reform, including redistribution of land to the farmers and insurance to them of a fair share of their crops, reorganization of both central and local administrations, the abolition of slavery and the development of technical education.
Upon returning to prominence at Suwon Castle, Chöng's teachings and scholarship was soon adapted to what, in Korea, has been known as the 'social reform' or 'Castle Doctrines'.