The general yulin map(fish-scale-shaped map for land registration) was a creation of the Southern Song Dynasty.Li Chunnian and Zhu Xi both designed yulin books and maps for land registration.Historically,the yulin map refers to the general yulin map,without exception.Although the yulin maps of the county,township and du or district differed in terms of administrative level,they were all topographical.The yulin books recorded in Ming Taizu Shilu refer to all the yulin maps and books submitted by local authorities.A yulin map is different from a yulin book both in form and function:the former refers to one or more topographical maps outlining plots of land,the latter to map books consisting of hundreds,even thousands,of maps of single plots of land(detailed maps of land holdings).The general yulin map was a map of land in a particular area drawn individually and put together.Its function was to show the shape and location of each piece of land,with the aim of enabling landowners to identify their lands in the field more easily.