Investigation and study are the most central and crucial link[1]

(December 4, 1944)

Among the nine guiding principles, the two most important are investigation and study, and distinguishing between right and wrong, major and minor issues. Of these two, investigation and study are the most central and crucial link. Under no circumstances should anyone be mistakenly identified as a spy without investigation and study, or when such investigation and study are superficial and lack genuine evidence. This point must be made fully clear to all cadres.

[1] This is a passage added by Mao Zedong while reviewing and revising a directive drafted by the Secretariat of the CPC Central Committee for the Shanxi-Chahar-Hebei Sub-bureau and other bodies on the issue of examining cadres and combating counterrevolutionaries.