The Japanese military section had been located in Hut 10, originally home to the Bletchley Park air section. Its expansion during 1943 forced it to take over rooms in Hut 4, the former location of the German and Italian naval section, which had moved into one of the new purpose-built blocks that were replacing the old wooden huts. But so many army messages were being sent over Japanese naval circuits, and in a number of cases using JN25 and other naval codes and ciphers, that it was eventually decided that all the Japanese sections needed to work together, and they were moved into Block F, the largest of the newly built blocks. This consisted of a number of wings jutting off a long, central corridor which, as a result of its length and the proliferation of various Japanese subsections in the block, became known as the ‘Burma Road’.
Most of the sections dealing with Japanese Army material were a mixture of Intelligence Corps personnel, Foreign Office civilians and members of the Women's Auxiliary Territorial Service (ATS), many of whom did extremely repetitive work preparing messages for the codebreakers to tackle. Gladys Sweetland was sent to the mysterious ‘Station X’ as a young ATS corporal:
I went for an interview at a place in Praed Street, in London. We were there for several days being interviewed by lots of different people, most of them officers. Then finally we were told we were being transferred to Bletchley. It was really rather weird. I was taken to a billet in Bedford, dumped off on the door with all my kit, given a travel pass and told to report to an administration officer the next morning. I was taken into a hut and introduced to what I was supposed to do. An officer explained it to me in great detail and it sounded so complicated I thought: I'll never be able to do that. But after he'd gone another officer came over and said, ‘Did you understand all that?’ I admitted I hadn't understood a word of it and so he explained it to me in much simpler terms.
Teleprinter sheets of coded messages were handed to me and I had to copy each message out in different-coloured inks across one line on large sheets of graph paper, a bit tricky when some stretched across four different sheets. Each message was marked with a sign to indicate which colour ink I should use. When I had completed copying one batch of messages out they were collected from me by one of the codebreakers and I was given another batch to copy. There were about ten people doing this on each shift, 8 a.m. to 4 p.m. and 4 p.m. to midnight. There were only two ATS on my shift, most were soldiers who were either no longer A1 or were considered too old to fight. I know it sounds ridiculous but we never asked what they did with the sheets of messages. It was all so secret. Even with the other girls in the ATS we only ever asked, ‘Where do you work?’ And they'd say, ‘Oh, Hut 6’ or ‘Block F’ or whatever. We never asked each other what we actually did.
We were given travel passes to come in by train during the day, which was similar to going to and from work in ‘civvy street’ and, provided one stayed clear of male and female Redcaps, it was fairly easy. When we finished at midnight there was a bus which would take a whole load of us home, dropping everyone off at the various villages where they were billeted and it depended on how many of you there were, and what route the bus took, how long it took you to get home. The first woman I was billeted with was rather peculiar. She had two young children and wanted me to stay in and look after them all the time so she could go out. The second was much nicer. She was middle-aged. She had a son who was in the RAF and her attitude was that if she could treat people billeted with her kindly, then perhaps other people would treat her son the same way. She would insist on bringing me breakfast in bed after I had worked the late shift.
When we moved into Shenley Road Camp at the end of 1943 life became more complicated. Shenley was a bit grim when we first went there because it had been raining. But eventually it dried out. The huts slept about thirty people and were heated by two old army stoves, one at each end, which didn't throw out much heat. We had to follow the rules of the camp and read daily orders, take part in marches, PE, etc. and stay in on Tuesday (called Barrack Night) for lectures, kit and hut inspection. One could only escape this if on evening shift. We were separated from the men's camp by the coal yard. We were allowed to walk through it but not to linger.
When we moved into camp, I bought a bicycle and spent many a pleasant time cycling round the countryside. Bletchley Park was a wonderful location and sometimes we just sat in the grounds in fine weather for our break. I had a boyfriend who was transferred into our office after being invalided back from the front line. But there was a whole group of us who used to go around together to pubs and concerts. There was an assembly hall just outside and it was there I got my love for opera and ballet because I saw the D'Oyly Carte touring company and the Ballet Rambert. There were also discussion groups where people would play classical music records and then explain the merits of the various pieces. I shall never forget the comradeship and meeting all those different types of people who were there. I never thought, leaving school at fourteen and a half, that I would be able to have a proper conversation with a university professor.
As a result of the work done by young women like Gladys Sweetland, the codebreakers’ task was made much easier. The main army air code under attack at Bletchley at this time was the Army Air Force General Purpose Code, designated 3366. It was a four-figure system with a numerical additive applied in much the same way as 2468. Although Joe Richard had hit a brick wall when trying to gain an entry via the identical Rangoon–Saigon texts, both Delhi and Bletchley Park had enjoyed more success and the Japanese military section at BP managed to break the code not long after the breaking of the Water Transport Code.
Maurice Wiles was moved from the Japanese military attaché section to the team decoding the 3366 material some time in the first half of 1943:
The main work was done by four of us. Alexis Vlasto, who was one of the few who had not come via the Bedford school, was in charge. He was a Japanese and Russian linguist. Very quiet, very relaxed, with a nice ironic sense of humour. George Ashworth, later Registrar of Manchester University, was the quickest mind among us. He had a wonderful memory. He would say, ‘Oh, I remember something similar to that four months ago.’ The other was Mervyn Jones. He was a more reserved character, but with a similarly lively mind and a delightful sense of humour. I remember the day the war ended and there was nothing to do, he came in and pulled out an Aristophanes text and sat there chuckling away to himself. Then he put that away and pulled out a musical score.
Despite Ashworth's brilliant memory, the section needed a record of code groups and information passed on the messages if it was to keep control of the system and rebuild the book. Elsie Hart, an ATS staff sergeant, was recruited to set up an index:
I was called up to an ATS station, I think in Northampton, where they sorted us out and a few of us were kept back. We had to go to London for interviews and an intelligence test after which we were told to report to Euston Station. Nobody knew where we were going but we were taken on a train to Bletchley where we were billeted in various villages in the surrounding area, fleets of buses ferrying us to and fro. I was billeted in a little village called Wolverton. It was a bit sparse and they were a nice couple but unfortunately her greeting was a bit off-putting: ‘Of course, we had to have you,’ she said. ‘We had no choice.’ I then went into one of the wooden huts where I was interviewed by a captain and a colonel and from then on I stayed in that department setting up an index.
It was an index of the dendai, which is the Japanese name for telegram. The messages came through on sheets of paper which had been decoded. I had to devise a scheme so I could sort it out. I think I must have filed them under the names of the officers. I hadn't been on a Japanese course but gradually I picked up what I needed to know and Maurice Wiles helped me. In the end we had a crypto-index as well as this military one. I used to get calls from other parts of BP about what I had noted in this index, usually on the name of an officer.
‘Elsie's Index’, as it became known, was an invaluable working aid to the codebre
akers, Wiles recalled. ‘She was a lesson to me coming from my public school background, the sheer ability. Her combination of high intelligence, dedication and unfailing good humour made Elsie's Index the hub around which the activity of the section as a whole revolved.’
While working at Bletchley, Elsie fell in love with another young codebreaker, John Griffin, who was a close friend of Wiles. ‘It was quite a small department and we all got to know each other quite well,’ she said. ‘John had a particular friend in my department and they were billeted together in what was then a little village called Newport Pagnell.’
John Griffin, George Ashworth, Mervyn Jones and Maurice Wiles were all keen table-tennis players and played against each other in their spare time, Wiles said.
Fiercely competitive foursomes were marvellous relaxation during times of intense work. As a civilian I belonged to the Home Guard, which was a bit like Dad's Army. We weren't very efficient. There was a good deal of competition between the two platoon commanders and we had night exercises. Alexander Aitken, the Scottish chess champion, was one of these people whose limbs are very uncoordinated. Marching alongside him was often very comical. There were a lot of very good chess players at BP. We used to have evenings when Hugh Alexander and Harry Golombek, both members of the British chess team, would take on twenty boards.
I found the codebreaking a stimulating mental activity. I think, being a civilian, it was very easy for me to have an easy relationship with the senior hierarchy and the most junior person, although that was certainly true of many of those who were in the services as well. I felt it was a very relaxing way to work. There were certainly boring periods. It's a much longer-term thing than a crossword and it was vital in codebreaking to do the groundwork first, to read through the text first, because that can be how you begin to spot the patterns.
The Japanese military intelligence section received material from the Japanese military attaché section, the army air material decoded in Vlasto's section, enciphered intercepts from Brisbane, Delhi and Arlington Hall, as well as anything arriving in the Japanese naval section that related to the Japanese Army.
The JMA material provided valuable information on the movement and existence of military units, as well as detailed intelligence – through the Tokyo Circular, the briefing paper sent to all Japanese military attachés – on Japanese activity on the various fronts. The most valuable naval codes were: JN25, which provided material on a wide range of subjects and was commonly used by military units in the major naval bases to pass their own traffic; JN11, the auxiliary fleet system, which contained a great deal of information on the movement of troop convoys and the locations of various military units; JN40, the merchant-shipping code, which also provided very valuable information on the movement of troop convoys; and JN147, the minor operations code, which often contained quite useful intelligence on local troop movements. There were a number of joint army–navy systems specifically designed for liaison but these produced very little intelligence.
Many of the decrypts that the section was working on arrived by teleprinter or from neighbouring sections, but since a lot of the material from overseas stations had to be sent by bag, it could be several weeks old by the time it got to Bletchley Park. Nevertheless, even these decrypts could have a great deal of current operational value, largely because the great distances involved in any campaign in the Far East and Pacific regions meant that Japanese movements had to be planned well in advance; one Japanese division took four months to move from its base in Korea to Burma. Strategic plans were often discussed and rehearsed many weeks in advance.
The section was under the control of Don Parkin, a Foreign Office civilian who was popular with his staff of mainly ATS and Intelligence Corps officers and NCOs, among them John Burrows, who after escaping from Singapore had been commissioned and sent to Bletchley Park. Betty Vine-Stevens was one of the ATS senior NCOs producing intelligence reports on Japanese military activity:
I and some friends walked out of college in August 1941 because we thought we were wasting our time when we should be doing something for the country. One had to do one's basic training and then everyone was tested to see what job they would be best at. Because I spoke a bit of German, they sent me off to Devonshire House, the headquarters of MI8 – the branch of military intelligence that dealt with Bletchley Park. The interview was conducted in German but was quite simple, so I could cope with that. One didn't know where one was going, no-one had heard of Bletchley at that time, but we were taken along in coaches and dumped outside civilian billets.
She was put to work on ‘paraphrasing’, turning the decoded messages into intelligence reports so that their source could not be traced and the secret of the broken codes remained intact.
One was given these messages and you had to put them into different wording so that it could be put out in this disguised form. Everything went out under a double-envelope system with different addresses. There were a lot of numbers on the outside one so that the dispatch rider could tell where it was supposed to go and then someone else opened it and sent it on to the address on the inside envelope. But as with everything we did, we knew very little of the next step. I decided in my own mind that the reports probably went direct to Churchill or to other Allied leaders.
It was a large section but I do remember a number of people: Captains John Burrows, John Humphries and John Brett-Smith; Sergeants Sandy Sanderson and Trixie Taylor; Lance-Corporal Jimmy Bentley; and Sergeant Mark Glover, whose wife and son were killed in London by a doodlebug. I shall never forget that poor man coming back on duty and saying, ‘All I found was my boy's tie.’
Sergeant Glover's brother-in-law was the pianist Jack Byfield and he had been to BP to give us a recital. We were well blessed with recreational activities such as sport, drama, music, etc., and, despite much repetitive and sometimes rather boring duties, the atmosphere was happy and relaxed, with the usual services humour. While small fry like me did not fully understand the importance of our own input, we did understand that it was imperative that we kept at it and that we did so in the utmost secrecy.
The fact that much of the material that the Japanese military section worked on came from abroad, and in particular from Arlington Hall, also led to a great deal of competition between the codebreakers at Bletchley and their US counterparts to get material out first, to the extent that at times Arlington Hall was almost regarded as the enemy, said Maurice Wiles.
We felt very detached from the Japanese and there wasn't much feedback. We weren't really seeing the impact of what we were doing. But we swapped what we were doing with the Americans and there was a sense in which they were the ‘enemy’. The word enemy has to be in inverted commas but research people are always very keen to get their research out first. When you're doing a crossword you don't like being told by someone else what the answer is. There were great cries of dismay when they told us something first and jubilation when we did it to them.
16
THE BLETCHLEY PARK STRIPPERS
By the spring of 1943, the British had become convinced that it was pointless if not foolhardy to rely on the Americans for Japanese naval material and were committed to building up their own code-breaking operations both at Bletchley Park and in the Indian Ocean area. The irritation and frustration over the US Navy's attitude towards co-operation had culminated in the discovery that the Americans were holding back a large number of ‘pinches’, captured codebooks that would have been of immense use to the British codebreakers.
The various pinches, which covered a large number of other codes and ciphers, including JN25, came as a total surprise to the British, who asked for a complete catalogue of captured Japanese naval material, most of which they discovered had been retained in Hawaii and Melbourne.
The Admiralty made its displeasure clear and the measures to improve the Japanese naval operations in Kilindini and Bletchley Park in order to make them more independent of the American operation forged ahead. The difficulties of r
eception in East Africa were to be resolved by a move back to Colombo as soon as circumstances allowed. In the meantime, Jon Cohen and Hugh Denham were sent to Kilindini along with another Japanese-speaker from Captain Tuck's most recent course.
They would be followed by a large number of Wrens in order to fill the desperate need for more reliable clerical assistants than the Temporary Women Assistants recruited from among the local expatriate community. Their role would be to strip off the ciphers and to operate the Hollerith tabulating machinery.
‘We went to Mombasa by landing ship from Merseyside to Takoradi in the Gold Coast,’ Cohen recalled. ‘Then from there flew to Lagos, spent two weeks in Lagos, which we hated, then by plane to Khartoum and then to Nairobi and finally by train to Mombasa.’
Their arrival coincided with something of a revival for Kilindini. The JN25 code had split, with two separate codebooks and three different methods of encipherment in operation. One of these systems, JN25e11, was available in Kenya in far greater quantities than elsewhere, giving the British codebreakers access to a depth of messages not available to the Americans. For the first time, the Kilindini station managed to exploit the Hollerith tabulating machinery to its full potential. In addition, a new transmitter was set up to allow them direct communications with Bletchley Park and two more Type X cipher machines were introduced to speed up the flow of recoveries.
The new codebreakers had been commissioned as sub-lieutenants in the Royal Navy and had been forced to wear uniform on board the landing ship taking them from Liverpool to West Africa. But when they arrived in Kilindini, Keith, who had been used to the more relaxed atmosphere of Bletchley Park and knew its advantages, told them to revert to civilian clothes, Cohen said. ‘Bruce Keith didn't want us to wear uniform because we would then start being ordered to do all the sort of things that would take up time.’
The Emperor's Codes Page 23
