An Authentic PURPLE Message

This is part 1 of the message which Japanese diplomats delivered to the U.S. Secretary of State on December 7, 1941. Several notes, written in pencil near the top of the message, require explanation: 6th is the date of the message (Tokyo time). ARMY indicates that the message would be processed by the U.S. Army (at that time the Army handled PURPLE traffic on even days of the month and the Navy handled odd days!). Pt. 1 warns that this is the first part of a multi-part message. 15739 is the motion indicator, which tells the recipient where to set the switches before deciphering the message. The indicator was enciphered before transmission. The numbers 9‐1‐24‐6 represent starting positions of the sixes switch and the twenties switches #1, #2, and #3 respectively, while the circled 4 designates the switch motion. The keying information required to decipher this message with the simulator is: Sixes=9 Switch #1=1 Switch #2=24 Switch #3=6 Motion=4 (231) The alphabet for this message is: Sixes: NOKTYU Twenties: XEQLHBRMPDICJASVWGZF The first four groups of plain text are: FOVTA TAKID ASINI MUIMI However, the majority of the message is in English. To Download the ciphertext of this message, click Here.

Created on ... August 26, 2002