[This is part of Chapter 4 of 'Espionage and the Roots of the Cold war' (Frank Cass, London). The book deals with the connection between underground communist political activity and Soviet espionage from 1917 to 1940s.]
On May 1, 1929 an unusual meeting of trade unionists took place in Shanghai. The communists who organised the meeting later regarded it as 'perhaps the biggest single feat of illegal organisation' at the time.
It was a copybook version of the kind of illegal activity under conditions of savage repression which was described by the Comintern Commission on Illegal Work: