Old He Tou is mentioned as someone who provided descriptions to Han Lei during her time in Yong'an City. Han Lei used his descriptions, along with those from several military doctors, to draw a map of the Great Jing Dynasty. The map depicted the distribution of various prefectures in the dynasty, as well as some major mountains and rivers. Old He Tou is referenced only briefly in the narrative as a source of geographical information for Han Lei's map.
