All confidential documents must be destroyed[1]

(December 26, 1940)

Regarding whether the destruction of confidential documents has been carried out, you should anticipate that during movement you may encounter special difficulties, may come under attack, and may suffer losses. You must view the situation as particularly serious. On this basis, in addition to exhausting all means to overcome difficulties, you must destroy all confidential documents without exception, leaving not a single scrap of paper behind. All incoming and outgoing dispatches and manuscripts must be destroyed immediately after reading, or must be carried on the persons of the most reliable comrades, and you must study in advance how to handle them in case of danger. This matter applies not only to the military headquarters but must also be ordered to be implemented throughout the entire army in southern Anhui, leaving not a single scrap or word of confidential documents. This is of the utmost importance.

[1] This is the main content of a telegram from Mao Zedong and Zhu De to Xiang Ying.