A Jesuit World Map? A Forgery? Making Sense of a Newly Discovered World Map (Kunyutu 坤輿圖) From Switzerland

Kun Yu Tu 坤輿圖 is a large world map on silk recently discovered in the basement of the Military Library in Bern in 2018 and donated to the Library of Zurich this year. The map is in Chinese and appears to display features common to Jesuit world maps such as those of Ferdinand Verbiest and Michel Benoît. Who made this map, and why? Close examination of the Swiss Kun Yu Tu reveals that it is a sister copy of a now inaccessible map from the First Historical Archives in Beijing. While this map seems to deviate strongly from other known world maps, there is no strong reason to doubt its authenticity. This paper argues that the deviations can be explained by the fact that the author of the map is not a Jesuit, but likely Zhuang Tingfu 莊廷旉a Chinese scholar with strong interests in Western mathematics, who during the Qianlong reign invented by a new type of cartographic projection similar to the azimuthal stereographic projection and used it to draw a map resystematizing the content of the Verbiest world map. The evidence linking the Swiss Kunyutu with the Daqing tongshu zhigong wanguo jingwei diqiushi 大清統屬職貢萬國經緯地球式 made in 1794 by Zhuang Tingfu relates to the common projection used, the place-name content of the two maps and the cartographic elements. The Swiss Kun Yu Tu is thus a valuable cartographic artefact which challenges the idea that Chinese cartographers were not able to create maps within the framework of mathematical cartography.