Here is the theater herald for The Secret Code (1942) Columbia serial. The Black Commando, a competing action hero to Republic's Spy Smasher, fights Nazis through fifteen chapters. See The Files of Jerry Blake for a detailed decoding of the serial. Interestingly, especially for a kid into cool stuff, the code tutorials at the end of each chapter were informative. I wonder how many kids sent around coded notes in their classrooms after seeing The Secret Code?
