20

Nyrambla

By the second half of 1942, the Japanese controlled an arc of islands to the north of Australia, including Timor, Bougainville, New Britain, and much of the Solomon Islands, as well as the north coast of New Guinea. From airfields in these locations, they launched continual air raids against stretched and depleted Allied forces in northern Australia and southern New Guinea.

Despite this, the Australian mainland was no longer considered to be under direct threat of invasion. The Japanese plans to capture Port Moresby had been thwarted at the Battle of the Coral Sea, and their forces were now re-grouping at Rabaul. Melbourne now seemed too far from the action for MacArthur’s liking, so he moved his headquarters to Brisbane in July. The Australian government provided him with use of the AMP office tower in the heart of the city — a building chosen in part because of its solid, reinforced-concrete structure, which meant that it would withstand an air raid better than most. General Akin went with him, and, with Akin, so did Central Bureau.

Central Bureau were assigned a large, two-storey house about ten minutes’ drive north-east of the city centre, at 21 Henry Street, Ascot. It was conveniently located, close to Akin’s office in the AMP building in one direction and a new airfield that the US army air force had recently built at Eagle Farm in the opposite direction. This airfield became the delivery point for incoming material from intercept field units.1

The house was a huge, old double-brick homestead with high verandahs and woodworked awnings, built in the 1880s on an acreage on the outskirts of the city. The original owner was a wealthy banker named Henry P. Abbott, who named the house ‘Nyrambla’, an Aboriginal word whose meaning was not recorded. When Abbott retired, he sold Nyrambla and moved to Sydney. The property passed through a succession of owners. As the city grew, the surrounding farmland gave way to suburbs, and the acreage itself was subdivided and sold. The street in front of the building was named Henry, and the street behind named Abbott.

The Queenslander magazine ran a feature article on the property in 1932, noting the six bedrooms, upstairs sitting room, and a two-storey rear wing for maid’s quarters, kitchen, and breakfast room. The magazine described the cavernous ground floor:

There are a number of fireplaces in the house with tiled hearths and marble mantelpieces. The hall is wide and high-ceiled. It is divided by two arches. The one nearest the front door is occupied by a doorway of cedar. The arch itself is filled in with glass, divided by bars of wood, the whole resembling an open fan. The door below and its side panels are of red glass. The panels on each side of the big front door also are of red glass, each with a woman’s figure marked on it in white, and the name ‘Providencia’ beneath one and ‘Hospitalita’ below the other.

A visitor approaching Nyrambla from Henry Street was met with the showy opulence of the front entrance:

Two bay windows open on to the front veranda on each side of the porchway and on to the balcony above. This porchway is arched above the set of front steps, with the name ‘Nyrambla’ marked thereon in black letters. The paving of the porch is of black and white tiles in large squares. Columned arches form the sides of the porch. Beyond the second arch, towards the rear end of the hall, is the staircase. It is of cedar, like all the rest of the fittings in this well-built house, but its railing is of iron.2

The small American contingent of Central Bureau, all of whom had been in Melbourne for only a few months or less, were the first to move up to Brisbane. After inspecting Nyrambla, they found it to their liking and moved in, taking up residence on the upstairs balconies. When Sandford arrived, they were evicted and sent to find billeted accommodation in surrounding suburban homes. The organisation was about to expand, and the whole building, as large as it was, would be needed for operations.

Army renovators had fitted it out in preparation: the ballroom was divided with makeshift walls into a rabbit warren of small office spaces, while other areas had similarly been sectioned and divided in ways that the army acquisitions people imagined might be useful.3 Various rooms were allotted to either traffic analysis or cryptanalysis, or for processing bags of intercepts arriving from Eagle Farm airstrip.

New personnel arrived in dribs and drabs. Most of the Australians sent to Central Bureau had been hand-picked as suitable for intelligence work from military training camps across the country. Those that came from interstate arrived at Brisbane Central railway station, where they would be met by an army intelligence officer and escorted directly to Nyrambla, or sometimes first taken to MacArthur’s headquarters in the AMP building.

They were billeted in local apartments and hotels, but, in keeping with Sandford’s policy to isolate intelligence staff from the rest of the military, never stayed at regular barracks, and were discouraged from mixing with the thousands of Australian and American troops now stationed in Brisbane.

General Akin made it a policy not to visit Central Bureau, because he did not want to draw attention to its activities. Central Bureau was not his only responsibility; as MacArthur’s chief signal officer, he was responsible for the entire United States army’s signals operations in the south-west Pacific area. His arms-length approach gave the impression to many there that he had little involvement with Central Bureau, but in fact he was in regular contact with its senior officers, and over the course of the war made visits to Central Bureau’s intercept units and other field operations.

Brigadier John Rogers, the director of military intelligence, established a second office in Brisbane, where he spent most of his time from that point forward. As a result, the Military Intelligence Headquarters in Melbourne effectively fell under the command of his second in charge, the assistant director of military intelligence (ADMI), Lieutenant Colonel Robert Little. Like Rogers, Little had served in the First World War, and had been decorated for his role as field artillery battery commander in northern France. According to the citation, ‘by his personal bravery and initiative kept guns in action under adverse conditions’. Rogers increasingly focussed on operational matters and on liaising with the Americans, while Little took care of the back-room politics and liaising with Australian politicians.4

Rogers did not share Akin’s qualms about visiting from time to time, and neither did the head of the Australian military forces, General Blamey. Mic Sandford would give them tours of the Nyrambla operation, providing a breezy commentary as he escorted them from place to place.

On one occasion, Sandford was showing Blamey around when the pair walked into an office where a man sat at a desk, hunched down with his hands over his head, groaning. The staffer was Harry Waters, who suffered from chronic migraines. Sandford, not being familiar with Waters’ condition, was momentarily taken aback but quickly recovered, and with a wave of his hand remarked to Blamey, ‘It would drive you nuts, doing this stuff all day.’ Blamey nodded. With that, Sandford guided Blamey back out of the room and on to other parts of the building, his breezy commentary continuing with barely a break.5

Sandford was too busy for the hands-on work of traffic analysis. Pappy Clark had emerged as a natural talent in the area, so in September he was promoted from lieutenant to captain (and later to major), and was put in charge of all traffic analysis.

He had been, from the start, the joker of the section. During the group’s return voyage from Egypt to Australia aboard the Mendoza, the mood was bleak in the sweltering, inescapable tropic heat. The ship was overcrowded, and they were cramped and sore. Fist fights would sometimes break out. On a particularly hot day, Pappy Clark appeared on deck dressed in coat, gloves, and balaclava, shivering and swinging his arms as if to warm himself up. The sheer absurdity of Clark’s antics broke everyone up into laughter.6

Captain Clark’s priority now was to compile a list of Japanese army call signs and figure out what each one stood for. Other sigint centres, particularly the British Wireless Experimental Centre in Delhi, had been collecting call signs and had provided what they knew. From these, and from the daily stream of intercepts arriving in bags from the Eagle Farm airfield, Clark built the call sign catalogue.

He learned from Sinkov about the new traffic-analysis team at Arlington Hall who were keen to contribute. Clark would assign them analytical tasks, sending material to Washington for them to work on via the direct communication line between the two centres.

The Japanese army was not making his life easy. They were using a very complex system of call signs, which had at first baffled everyone. All the signs were encrypted in their own special code, completely separate for the code systems used for the message itself. This was not like the WE-WE code, which used a simple substitution method. This was a full-blown code of its own, complete with codebooks and additives. Clark called it the ‘place name code’. It was eventually broken at Central Bureau by Pappy Clark’s traffic-analysis section, with some help from Sinkov and Sinkov’s colleagues at Arlington Hall.7 The naval cryptanalysts also contributed with the provision of army call signs that had been sent on navy channels along with the naval equivalent of the same call sign.

Sinkov was still stymied by the three-figure codes. It started to become clear that the problem was so hard because the Japanese army was not using a single tactical code; it was using dozens of codes. This was made possible by the unusual policies of the Imperial Japanese Army. Low-level units were not allowed to communicate with each other, only with their parent units. Regiments didn’t talk to each other, only to their division command. Division commanders, in turn, couldn’t communicate with other division commanders, but always had to deal directly with their army headquarters, and so on, up and down the chain. Although it might sound very inefficient, this meant that each communication line could use its own unique code system. The traffic analysts contributed to this astonishing discovery as they pieced together the structure of the enemy’s army.8

Japanese tactical-code systems proliferated across the south-west Pacific. They emerged from mysterious units in the uncharted wilderness of New Guinea, from islands to the east and west, and from further north. They came and went like fireflies in the dark. There was never enough traffic in a three-figure code; just as a solution began to emerge, the code would vanish, and the intercept stations would hear it no more.

Solving the various puzzles involving codes, traffic, ciphers, and call signs needed lots of data — and that meant more intercepts. The Japanese army was not making it easy. Central Bureau was stymied by certain Japanese army practices that thwarted their attempts to collect large numbers of messages for each system. The army units were talking to each other on low-power transmissions with limited range, making the messages hard for the intercept stations to pick up clearly unless they were close by. A unit would send a brief radio burst at high power, enough to make contact, and then turn down the power so that the transmission was barely strong enough for the recipient to receive it, and no more.

An Australian intercept site at Coomalie Creek or Townsville was too far away to pick up many of these quiet, low-power transmissions. More intercept units were needed, and they were needed as close to the enemy as possible.