Jeong Yak-yong was a Joseon scholar of the Silhak, or "practical learning", school, remembered chiefly for his writing on law, government and agronomy, and in architecture for one commission that reorganised Korean fortification. Asked by King Jeongjo to design Hwaseong, he weighed Korean, Chinese and European precedents and produced a plan gathering a defensive wall, a garrison and a working market town into a single enclosure. His most consequential decisions were technical: fired brick, almost unused in Korean military building, for parapets, ravelins and watergates, and a hoisting device, the geojunggi, that cut the labour of moving cut stone. UNESCO credits the design to him by name. From 1801 he spent eighteen years in internal exile in Gangjin.
