Li Yan chuckled and explained the method to her!
Before buying those seven maps, he had already been paying attention to the map descriptions in various shops.
Alongside the brief description of each jade-slip map, those introductions also included a broad overview map.
That overview map had little practical use; it merely showed the approximate outline of the region. Otherwise, customers might not even know where the map being sold covered.
Li Yan had memorized the outlines of many different regions, and all the descriptions he examined concerned areas to the southeast.
Although jade-slip maps were protected against prying by various means before cultivators purchased them, their outlines were not concealed.
When different shops sold jade-slip maps of the same region, some drew broader outlines and others narrower ones. Li Yan had memorized all those differences.
By focusing on the edges, Li Yan could match certain places together. Even where pieces were missing, the many outline maps he had memorized allowed him to fit other regions into the gaps...
Mei Hongyu was dumbstruck after hearing his explanation. She had never known this was possible, and even if the merchants discovered it, there was absolutely nothing they could do.
They could hardly leave the outlines of their jade-slip maps out of the descriptions. If they did, prospective buyers would have nothing but a few lines of text to look at.
Simply saying that a jade slip mapped somewhere to the southeast covered far too broad an area. They might end up with pitifully few buyers.
After thinking it over carefully, Mei Hongyu felt that even knowing the method, she would find it extremely difficult to accomplish this.
It would require observing all kinds of jade-slip maps over a long period and constantly studying them before there was any chance of achieving