During WWII, this model of the Japanese Type-97 cipher machine was know to American cryptanalysts as JADE. It was one of three varieties of Japanese machines that used a series of telephone selector switches to encipher or decipher top-level messages.  JADE was similar to another cipher machine, CORAL, with the main difference that JADE was used to encipher messages in Katakana using an alphabet of 50 symbols.

Top secret messages transmitted by JADE , CORAL And PURPLE machines were intercepted and decrypted by American Army and Naval personnel. The information gained by this source was instrumental in the Allied victory in the Pacific.

Although no PURPLE Cipher machine was ever captured  intact, it is believed that PURPLE looked very much like JADE .

This JADE machine was captured in Saipan in June 1944  and is now on display at the National Cryptologic Museum.  JADE was a stepping-switch crypto system used by the Imperial Japanese Navy for secure communications from late 1942 until 1944. (Photo by Jerry Proc)

Another view . (Photo by Jerry Proc)

A closer view. Click to enlarge. (Photo by Mark Pellegrini)

Contributors and Credits:

1) http://en.wikipedia.org/wiki/JADE
2) Placard at NCM.

Apr 26/12