Deciphering enemy secrets: Craig Collie’s Code Breakers

Most Allied World War II victories were the product of painstaking, insightful, sometimes brilliant codebreaking.

Battleship USS Arizona topples over during the Japanese surprise attack on Pearl Harbor.

Admiral Isoroku Yamamoto, architect of Japan’s treacherous but stunning attack on Pearl Harbor on December 7, 1941, was a brilliant strategist. Yet he knew his skills were tempered by his nation’s military and material limitations. Informed of Japan’s success in devastating the US Pacific fleet, he mused that all Japan had achieved was to awaken a sleeping giant and fill it with a terrible resolve.

That was accurate in every detail, but what the admiral could not foresee was that American resolve would include his death as retribution for the slaughter at Pearl Harbor, and in direct consequence of Japanese propaganda declaring Yamamoto would dictate the peace terms to the Americans in the White House.

Code Breakers, by Craig Collie

In Craig Collie’s Code Breakers, Yamamoto looms large in the sections on the turning points of the Pacific War: the battles of the Coral Sea and Midway, the ambush of Yamamoto’s plane by American fighters over the Solomons.

All these allied victories were the product of painstaking, insightful, sometimes brilliant codebreaking by American, Australian and British signals intelligence analysts.

Collie has previously written a splendid account of the Kokoda campaign from a Japanese perspective: The Path of Infinite Sorrow (2009), with Hajime Marutani, which was penetrating in its research and original in its conclusions. His other books on the bombing of Nagasaki and the Chinese republican revolution make him a fine wartime historian.

Code Breakers, an engaging and enlightening book, adds to this authority. It is the best book on the significance of cryptanalysis in the Pacific War since Elliot Carlson’s Joe Rochefort’s War (2011), a biography of the renowned American codebreaker at Station Hypo, Hawaii.

Collie traces the stumbling development of Australian efforts at signals intelligence before World War II. It is a story of political hesitation overshadowed by imperial assertions of power.

One episode tells an epic story. The perceptive lieutenant commander Rupert Long, the director of naval intelligence, recommended to the chief of naval staff of the RAN, admiral Ragnar Colvin, that a dedicated signals unit be established in Australia to intercept and decode the radio traffic of potential adversaries, particularly German transmissions.

“The Colvin proposal was considered by the Defence Committee in early 1940 and passed to Prime Minister Robert Menzies in April,’’ Collie writes. “Menzies was unconvinced. Most enemy — that is, German — messages were transmitted in Europe and the Atlantic, and he saw FECB (Far East Combined Bureau) as already covering Asia. Nonetheless, he wrote to the Dominions Office seeking the views of the British government. It was in no rush to provide them.”

Menzies’ reliance on British decision making nearly had serious consequences for Australian capability and security: “In October, 1940, Britain’s Secretary of State for Dominion Affairs, Lord Cranborne, finally replied to Prime Minister Menzies, saying he saw no reason to set up a large-scale intelligence body in Australia.”

Despite this, an Australian cryptanalysis capacity did emerge, with regional backing not only from British naval personnel in the region but from the Dutch (East Indies) and New Zealand. The prime mover in this policy, which saw the establishment of the Special Intelligence Bureau, was the RAN director of signals and communications, lieutenant commander Jack Newman.

This fundamental step enabled Australia to contribute consistently and constructively to the Allied signals interception and decoding effort from 1942 to 1945, deciphering messages and analysing Japanese military strategy and movements.

Japan’s deluded war aims opened the door to precisely this manner of cryptanalysis. Japan was determined to dominate the Asia-Pacific war zones from the Aleutians to the Andamans. To communicate with its far-flung armies and navies, Tokyo relied heavily on coded radio signals. And as with grand admiral Karl Doenitz’s communications with his U-boat commanders in the North Atlantic, Allied codebreakers meticulously reconstructed messages and broke open the codes.

And like their German allies, confident that Enigma was unbreakable, Japan relied on the complexity of its changing Kana syllable clusters, its codebooks and the ambiguities of its language to prevent deciphering. The Japanese gambled mightily and lost badly.

Among the outstanding Allied codebreakers was commander Eric Nave of the RAN, who had spent years in British service in Hong Kong and Singapore. Having broken J19, the Japanese diplomatic code, it was Nave who deciphered the “Winds” message to Japanese embassies on what must be done in the wake of an outbreak of hostilities. The final warning from Tokyo was to be incorporated in a weather report.

The Australian contribution to signals intelligence — with intercept stations from Park Orchards outside Melbourne through to Townsville — along with naval analysis at FRUMEL (Fleet Radio Unit Melbourne) and the Central Bureau for the army and air force, was constantly subject to the tensions and tides of Allied co-operation.

The Americans had arrived in Australia in strength after the fall of Corregidor in The Philippines. Indeed, Collie’s chapter on Corregidor is the highlight of the book. It is possible to sense the heat and perspiration, under bombardment, of the confined spaces in the Malinta Tunnel.

However, some among the Allied codebreakers seemed to spend as much time warring with their own side as concentrating on the fight against the Japanese. Collie sheds new light on the Australian war effort, moving steadily yet missing little of significance in the Pacific, from Lae to Leyte.

There are lighter moments, as in Collies’ references to artist Donald Friend’s war, from backbreaking labour on the Brisbane docks to codebreaking.

Collie notes acidly that unless Alan Turing or Bletchley Park appear in the story, Allied codebreakers are routinely denied honour and recognition.

Perhaps, but Code Breakers travels far towards filling this void.

Stephen Loosley is a visiting fellow at the US Studies Centre at the University of Sydney.

Code Breakers

By Craig Collie

Allen & Unwin, 400pp, $32.99