US Codebreaking Activities in Tokyo during the Korean War

I updated my recent article "Korean Cryptography" with additional specimens from John Milmore (2002), #1 Code Break Boy. The book, written like an unedited memorandum of an eyewitness, is interesting in recording US codebreaking activities on North Korean traffic during the Korean War, in which the author was "the principle cryptanalyst" (p.3).

It is more interesting to me because the codebreaking unit was headquartered in Tokyo (Japan was still under occupation after WWII). The photo below is a recent view of the building used as the headquarter (from Wikipedia).