The History of Hut Eight

Both UW CN are more or less impossible bigrams so we reject the position. Position HEK + 3 = HEN, however, looks like this:

Which we guess correctly as OHNESINNVVVMNOOO BOULOGNE the first N being just a stray letter in the dummy words. We are now well under way and have supplied the Banburists with 2 certain distances: with the distances obtained from the Freeborn catalogue in addition they will probably soon produce the correct alphabets.

The next move is to examine a tetragram fit between HIP and HEX - not a very good tetragram, estimated to have about 1 chance in 3 of being right. With HEX, HEN, + HEK cribbed we can easily prove or disprove this tetra and great is our delight on finding that it is the cypher text of the word DREI; this almost certainly a correct fit and the matter is proved beyond doubt when we crib the whole beginning of the message. With the amount of crib we now possess, attaching HIJ is not very difficult and we have a solid piece of depth on five messages.

At this stage it is certain that the Banburists will get the alphabet but we can still assist by confirming and by finding new distances on the Middle wheel. If we have two messages HOD and HIJ and know that, on the Right Hand wheel D + 1 = J, we can say that HOD starts in one of 50 positions in a known rela-


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