TheCodeBreakers
all differentials three previous systems X No dupes." Corregidor was not
to get the initial break into the new superencipherment until December
8. And the only other system in which the Yoshikawa messages might
have been forwarded—the flag officers' system—remained unsolved.
A possibility of warning was opened at the source, however, when
Yoshikawa's original messages became available to Rochefort's unit.
Mayfield had picked up another batch of cables in the surreptitious
fashion from Street on Friday morning and immediately sent them down
to Rochefort's unit by messenger. Solving them was not part of its duty,4
but when a superior officer and colleague asks one to do a favor, it is
hard to say no. Rochefort assigned the messages to Chief Radioman
Farnsley C. Woodward, 39, who had had some experience with Japanese
diplomatic codes at the Shanghai station from 1938 to 1940. He had
some help from Lieutenant Commanders Thomas H. Dyer, Rochefort's
annaabi.ee 
