Today I received a nice little package of stuff from Holland, courtesy of Rob van Meel, who reprints old military manuals – mostly British, but a few American and German ones too. I get the impression these are mainly for people with an interest in reenactment / war games rather than historians and researchers per se, but given a healthy area of overlap there’s surely room for everyone at the table. 😉

Unsurprisingly, I was most interested in the various Slidex-related manuals Rob had, particularly an updated release of the Slidex manual dated 1st December 1944 (i.e. six months after D-Day). You see, Slidex originated as a system where operators used only a single letter for each of the twelve slots on the horizontal cursor: yet we have later examples where two letters went in each slot (and you could choose either one to signify that column).

If our pigeon cipher is a bigram cipher, then it is one that appears to use 24 letters in its horizontal cursor. So if it was enciphered using Slidex (which seems to be the code most widely used on D-Day), it would have to have used the two-letters-per-slot version. Hence the big question I wanted to try to answer was… when did the changeover from one-letter-per-slot to two-letters-per-slot Slidex happen?

However, going through the revised Slidex manual, it became abundantly clear to me that even in December 1944, the British Armed Forces were still using single-letter-per-slot Slidex, which would seem to rule out Slidex’s having been used in the pigeon cipher before 1945.

At the same time, the two pigeons were (according to their NURP references) born in 1937 and 1940: and the older of the two would have been right at the end of its carrying days in summer 1944, let alone in 1945. As a result, the Venn diagrammatic intersection of possibility (i.e. between the [old pigeon] circle and the [revised Slidex] circle) is shrinking all the time.

Right now, I don’t know what the answer to all this is: to my eyes, what we’re looking at seems a bit more like a bigram cipher than a machine cipher, but even that’s far from certain either way. All the ‘best’ cipher mysteries seem to take a somewhat sadistic pleasure in continuously oscillating either side of the shaky line between certain and uncertain, and this one is surely no exception.

Yet there were other low grade bigram ciphers in use during WW2: two in particular were an Air Support bigram cipher and a Royal Engineers syllabic cipher. These may well be the same two variants of the Syllabic Cipher introduced in 1942 as per Stu Rutter’s page, which I believe were known as BX 724 and BX 724/RE respectively.

I’ve already written to several army museums and archives asking if they have either of these, but so far without any luck. Any suggestions as to private collectors (or collections) who may have a copy of either? Unless you have a better idea, this would seem to be the next sensible thing to check, and the various National Archives files Stu & I checked didn’t seem to have any description of it at all.

In short: probably not Slidex, so remains a work in progress. 😉

5 thoughts on “The WW2 Pigeon Cipher… probably isn’t in Slidex. :-(

  1. Let me throw some more fuel onto the fire …

    A while back I stumbled across some National Archive documents that suggested *all* British pigeon pads for Overlord were overstamped with “OPERATIONAL MESSAGE – Telephone to War Office Signal Office, WHITEHALL 9400” to ensure faster communications of messages. I must try to locate my copies.

    Interestingly it also suggests that American pigeons pads did not have this and also used codenames for recipients – I know British forces issues pigeons for the Americans but do not know if they issued British message pads as well, although you’d guess it was quite likely. So I wouldn’t completely rule this out as a American (or Canadian) message.

    I also wonder if the message pads and/or containers varied throughout the war and may be useful in re-exmaining/narrowing the date ranges – for example:
    – the 1942 Dieppe message matches this message pad
    – the 1944 Gustav message pad is very different albeit appears to be a RAF rather than Army version

    The Bletchley Park museum obviously has a collection of pigeon messages so may be able to help date the message pad?

  2. Anne-Lise Pasch on February 18, 2013 at 9:41 am said:

    > the older of the two would have been right at the end of its carrying days in summer 1944, let alone in 1945

    Might explain why it was dead in a chimney. Just saying.

  3. You’re kidding – they added the phone number?!

    (phone rings)
    Hello- Bletchley Park here
    (heavy German accent)
    I have a pigeon here with a message which says “Please move all your battleships 50miles to the north urgently – thank you”.

  4. Mike: I hadn’t read that, I saw plenty of similar things at the NA for individual pigeon services but not for Overlord – please let me know if you remember where you found it!

    As far as the pads go, “our” pigeon message is on a sheet from an Army Message Pad 418B (there’s one at the National Army Museum) used throughout WW2, which itself was a modified version of the Army 418 pad used in WW1: apart from narrowing it down to an Army pigeon (which is consistent with the red canister, and with the ‘j’ in “Sjt”), I’m not sure there’s much else meat to be had off that bone. 🙁

  5. Jonathan Sly on February 23, 2013 at 6:39 am said:

    Military paperwork rarely changes, it is fit for purpose. Though every decade or so it may get a revision eg they change the letter A to B etc. For an Example the MOD 1033 Kit issue form is still in use today 2012 as it was in the 80’s when I was issued my kit. Each service would have its own paperwork design to. so the pads would be different. What needs to be answered is there is a hand written figure next to the pigeon service. Each message has a different number. If this is a Senders ID then there must be a military or pigeon service log containing all ID’s. Especially as its Blank in any other form of ID. The other thing is the Big one is the Cipher, itself there were 30-40 ciphers being used. Each service had their own, as did the dipomatic section. we know it was an army cipher. The Tiger and Empire codes were Just two codes the army used and we can assume it is some sort of sitrep. eg enemy troop movement, please send air support we are in the mire, Every message I ever sent was Nothing to report, or Contact wait Out. The only two things those messages had in common was a grid Reference was included. The military always use block of fives even to this day as not to give word length. The Germans and the yanks seemed to have cracked or part cracked a lot of our ciphers. Therefore it is possible! I assume this a low grade cipher as it was sent by pigeon which leads me to suspect. The Wireless was out of use. Maybe hit, maybe Battery failure. But the Signaller was alive as he encrypted the thing in quick time. But that leads me to more questions. You’re heading up the Beach your mates are dropping like flies the Radio’s out of action. You turn to your mate and say “Quick pass me a pigeon! i’ll encrypt a message, inform Blighty we need reinforcements. No this message was sent from a secure location. Which means that the HQ element had arrived and set up a command and control post, complete with pigeons.

    Unfortunately I never dealt with pigeons so I would not know how that sort of message would start. By voice for example it would start by Zero this is Delta One zero, If we could could see a few messages and if there was a format then a Brute force attack may be possible.

    Another problem we have we cant go on the Rank really as it could have been a field promotion and his commanding officer may not have had to have the time to inform the war office. A good example was David Stirling who had put captains pips on when he was a Lt. when a friend Congraulated him, he said “I haven’tTheres so much brass around here they haven’t noticed. Usually when the troop sgt was hit the guy next to him was made up. Which may explain why nobody can find him.

    SJT does not help really either SJT was the usual spelling for Serjeant in the British and New Zealand Armies until 1953. Then it was changed to SGT. So only SJT is Historically correct for ww2
    Some Regiments maintain the tradition today and use SJT the Rifles being one.

    This isn’t a negitive post its a reality post some of the Evidence is superfisal at best.

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