송사
Following the Marco Polo Bridge Incident on 7 July 1937 the War of Resistance against the Japanese began. Deng continued his research at the Beiping Library and with the assistance of Fu Sinian and Zhao Wanli () completed a work containing "Chronicle of Xin Qiji's Life" (), "Annotated Works of Xin Qiji" () and "Treasury of Xin Qiji's Writing and Poetry" (). In August 1939 Deng travelled through Shanghai, Hong Kong and Hanoi to the newly established National Southwestern Associated University in Kunming, Yunnan Province. Here he became teaching assistant to Beijing University researcher Chen Yinke. In 1940, Deng followed Fu Sinian to Li Village, Nanxi County, Sichuan where from 1940 until Spring 1942 he received support from the board of directors of the Sino-British Boxer Rebellion Indemnity Fund () and began his research into the History of Song. At this time he also completed and published "Amended Government Functionaries Records from the History of Song" () and "Amended Criminal Law Records from the History of Song" ().