The early Ming state compiled two great fiscal archives: the Yellow Registers of households and corvee, and the "fish-scale" maps (yulin tuce), field cadastres whose irregular plot outlines packed together like fish scales. A nationwide cadastral survey in 1387 recorded each parcel's owner, dimensions, area and land class to forestall tax evasion by the gentry. Together household and land registers fixed who owed tax and labour on which ground, and they remained the basis of levies into the Qing. The system represents one of the largest pre-modern efforts to map and register land ownership.
The fish-scale cadastre is among the earliest comprehensive systems of mapped land registration, the documentary infrastructure of property and taxation that any developed urban land market requires.