You can also watch Cracking the Code on MagellanTV.
You can find this series on various documentary platforms and streaming services: _ing.the.Code.S01E03.The.Japanese.Super.Code.72...
This episode explores the story of the (the "Japanese Super Code"), which was used by the Japanese Foreign Office for top-secret diplomatic communications leading up to and during World War II [1]. It details how a team of American cryptanalysts, led by William Friedman at the Signal Intelligence Service (SIS), managed to reconstruct the complex Japanese cipher machine without ever having seen it [1, 2]. You can also watch Cracking the Code on MagellanTV