TheCodeBreakers
transformed the Chinese ideographs to four-digit numbers for telegraphic
communication. After the Japanese seizure of Shanghai early in 1932,
Morikawa was sent there as chief of a cryptanalytic unit attached to the
3rd Fleet. He solved a Chinese message that corroborated a slightly
doubtful Tokumu Han solution of an American GRAY message reporting
Chinese plans to use its Air Force to attack Japanese troops. Instead the
Japanese struck first, catching most of Chiang Kai-shek's Air Force at
Hangchow.
The Tokumu Han failed, however, to break two-part codes, such as
the State Department's BROWN code, those used by the American Navy,
and those introduced by Yardley into Chinese communications when he
was Chiang's cryptologist—except in extraordinarily favorable
circumstances. One such occurred on February 26, 1936, when two
regiments mutinied in Tokyo and several statesmen were assassinated in
an attempted coup d'etat. This furnished the cryptanalysts with an ocean
annaabi.ee 
