Greg Nedved from the Center for Cryptologic History at Ft. Meade, MD, would like to call researchers' attention to ISCOT. This was a British project during World War II to monitor the activity of Soviet agents by intercepting via radio their encrypted messages. It was quite successful, resulting in several volumes of decrypts. ISCOT includes a fair amount of information about the CCP-KMT relationship, e.g., discussion of Li Lisan. It also includes letters to Mao from his two boys, Anying and Anqing, then in the Soviet Union. The complete ISCOT set can be found at the National Cryptologic Museum's library, where it is available to researchers. If you have questions, you are welcome to contact Greg directly (This email address is being protected from spambots. You need JavaScript enabled to view it.). He can tell you which item numbers pertain specifically to CCP-KMT relations, but please don't ask him to do any other research for you.