One of only two known surviving examples in the world of a very rare type of Enigma machine is going on display at Bletchley Park for the first time this Thursday 14 March, almost 75 years after it was buried by retreating Hungarian forces near the Czech border in Southern Poland.
The G31 Enigma was acquired by the museum from a collector in 2016, after allegedly being dug up in a farmyard. The machine’s rotors and plugboard had been removed, exactly the top-secret equipment a retreating army would remove before disposing of it.
Conservation work has revealed the presence of a hidden serial number, 110, allowing the Bletchley Park Collections team to pinpoint the model to the year it was produced and where, revealing the machine to be much rarer than previously thought.
Thanks to research by cryptography expert Frode Weierud, and a listing from the Enigma manufacturer Chiffriermaschinen Gesellschaft Heimsoeth & Rinke from October 1935, it is now known that this machine was from the first batch of the G31 model ever made, and was one of 24 machines delivered to Hungary.
Not only that, but it is one of only 10 -20 Zählwerk Enigmas models known to survive, only three of which are on public display. Of these machines, it is one of only two known surviving versions of a Zählwerk Enigma with a plug socket in its side that allows it to be connected to a printer. The only other machine with this feature was auctioned by the German auction house Hermann Historica in October 2009.
David Kenyon, Research Historian at Bletchley Park, has also deduced that the area where this Enigma was discovered was the location of the final surrender of Hungarian forces to the Red Army in 1945.
Kenyon said: “There was not just one type of Enigma, but a whole family of different machines. It is exciting to discover an example of one of the rarest types. What makes this especially interesting is that our research has revealed the life story of the machine from its original manufacture and sale, to its sad fate at the end of the war. The object sums up in an individual way the wider story of world War Two.”
A research paper by Kenyon and Weierud on their findings on the history of this machine will be published in the academic journal Cryptologia.
Bletchley Park is believed to be home to the largest collection of Enigma machines on public display in the world. A new D-Day experience opening 11 April 2019 will reveal how the Codebreakers’ breakthroughs into Enigma and other enemy ciphers provided vital intelligence that shaped plans for the Normandy invasion.