Jan Kowalewski

From The Hidden War, 1978 by Robert Aymler Haldane

After the end of the First World War the Japanese engaged the services of a Polish expert, Captain (later Colonel) Jan Kowalewsky, to improve their standard of cipher work, lecturing totheir cadets onthe construction of ciphers and their unravelment. From himthey learnt what makes ciphers vulnerable. But it was from Ameirca that they probably obtained even greater help.

During the Twenties, whenamong the Western democracies disarmament was much in vogue, the American Black Chamber* which Herber O. Yardley had operated so successfully in the First World War was closed by Henry L. Stimson, the Secretary of State, by the simple expedient of cutting off funds. He did not approve of "reading other people's Mail".

Subsequently Yadley wrote a book about his experience and achievements; it proved a best seller. ^†   (Etc).

With the advice of Kowalewsky and Yardley, the Japanese set about devising a system which would enable them to compete with other powers by using ciphers of an exceptionall yhigh standard of security. This did not, of course, enable them to become siklled at unravelling others' ciphers, a field inwhich, as events proved,they were unable to compete; but at least it pormised to provide them with a system likely to defeat attempts of others to break it. In the early Thirties they purchased the original model of the Enigma which could then be bought on the open market. It was from this that the Germans later developed the highly sophisticalted machine used by their High Command.

* The origin of this term dates back tot he reign of Louis XV, whose mistress, Madame de Pompadour, set aside a room for cipher work and called it her Chambre Noire.

New York, London : St. Martin's Press, R. Halle, 1978, pp. 125-6.

^† Author Yardley, Herbert O. (Herbert Osborn), 1889-1958. Title The American black chamber / by Herbert O. Yardley ... Publisher New York : Blue ribbon books, inc., [1931]. Description 375 p. : front., ill., plates, ports., facsims. ; 23 cm.
Author Yardley, Herbert O. (Herbert Osborn), 1889-1958. Uniform Title [ American Black Chamber. Japanese] Title Burakku chienba : Beikoku wa ikani shite gaikō hiden o nusunda ka? / Hābāto Ō Yādori cho ; Ōsaka Mainichi Shinbunsha yaku. ブラック・チエンバ : 米国はいかにして外交秘電を盗んだか? / ハーバート・オー・ヤードリ著 ; 大阪每日新聞社譯. Publisher Ōsaka-shi : Ōsaka Mainichi Shinbunsha, Shōwa 6 [1931] 大阪市 : 大阪每日新聞社, 昭和6 [1931] Description 4, 466 p., [22] p. of plates : ill. ; 19 cm. [ University of California Catalog (WPT) ]