A collection of military maps of the area around the city of Nanyang, Henan province that Japanese drew up before invading the area are valuable for the study of Japanese aggression against China, 1937-1945, before and during WWII.

The 1: 50000 scale maps record every river, forest, village, and bridge along the route into the area, and are quite similar to the maps of today and, in the words of Fan Xiaowei, of the municipal archives, "are the most advanced, accurate and practical combat maps in the 20th century."

And, without the satellites and aerial photography that we have today, the question of how the Japanese made the maps is somewhat of a mystery. But, according to Zhang Huaizhen, a retired archives bureau employee, the Japanese army must have sent many spies and used local Chinese to collect information to make them so sophisticated.

Most of the maps were made around 1938 and contain the Chinese characters for "military secret". Historical records say that Japanese troops occupied the town of Xinyang, Henan and Wuhan, Hubei province in the autumn of 1938, then marched to Nanyang in May 1939, February 1941, and March 1945 in an attempt to reach Xi'an, Shaanxi province. The lines of attack coincide with places on the maps.

While the Chinese themselves have tragic memories of the areas associated with the yellowed maps, the archives personnel have scanned and digitalized the maps to help record the history of the War of Resistance against Japanese Aggression.