How Central Bureau cracked WWII codes

THE SECRET CODE-BREAKERS OF THE CENTRAL BUREAU:

WHAT WAS THE CENTRAL BUREAU?

*Joint Australian-United States signals intelligence organisation

*Formed in April 1942

*Headquarters in both Melbourne and Brisbane, later Philippines

*Inconspicuous name to hide top-secret job

*Started small but grew to staff of 4300

WHAT DID CENTRAL BUREAU STAFF DO?

*Broke into Japan's military forces radio traffic

*Laid bare Japanese intentions, formations and movements

*Supported General Douglas MacArthur's South West Pacific Area command

WHAT KIND OF CODES DID THEY DECIPHER?

*Japanese forces used Kana morse code system for air communications

*Kana signals based on 46 phonetic sounds plus 25 other sound changes

*Allied operators had to learn the 71 Kana morse signals

*Transmissions often came through at up to 50 words per minute

HOW DID THEY HELP ALLIED FORCES?

*Decrypted codes revealed Japanese intentions, formations and movements

*Used weather broadcasts to anticipate strikes on Allied territory

*Helped General MacArthur plot his island-hopping push in Pacific

*Helped decode Japanese Army's mainland code

Source: Official plaque unveiling ceremony booklet; Address by Intelligence and Security deputy secretary Steve Meekin