Menus with Single and Double Inputs with Subsidiary
This menu is shown in Fig 20 in the Report. Using setup text file
brfig20.txt and starting wheel order 352, brings up the 3rd entry in
the checking sheet in Fig 21. This is quite a good stop, 3 self-steckers,
one confirmation but two contradictions on V and Y.
I leave it to the reader to verify the other stops. (that's code for
saying I couldn't easily make them work!).
Same with menu in Fig 22, couldn't get the stops shown in the Checker
sheet in fig 23.
The Bombe Test Menus.
Menu I. This is a very strong menu which only gives one stop for all
wheel orders for 5 wheels. When I obtained the US Bombe Report from
NARA this was the first menu used to test Bombe simulators and it
immediately revealed the problem with the Bombe readout which I have
You can verify the single stop but I have set the setup text in
brmenu1.txt to cover wheel order 312 to 325. The stop comes up at
w/o 324 stop BUO Stecker letter 'L'. You can use the Checking Machine
to verify the other Steckers.
Menu II. This menu cannot be run on this Bombe simulator because
the menu requires 3 letters of offset. Normally only two letters are
required, the first letter, not included, is assumed to be 'Z'.
Menu III. The setup data text file brmenu3.txt is set to just run w/o 153 and it
brings up the second stop in the list, stop CBW stecker letter 'U'.
I have not yet managed to bring up the other stops listed.
Menu IV. This requires setup data file brmenu4.txt and just searches
wheel order 243. It requires the machine gun to be switched off since
the given stop LFT, has contradictions, i.e. two registers containing
the same stecker letter.
Menu IVA. This uses setup data file brmenu4a.txt and just wheel
order 243. The input is set to register E and current entry at 'A' which
via the diagonal board puts current into register A position E.
A spurious stop comes up first then the three stops quoted in the Report.
Again, the machine gun needs to be off since the stops contain
Menus V and VII. cannot be run because they requires three letter offsets.
Menu VI. is left as an exercise for those interested.
I hope this exposition, incomplete though it is, has given the reader
an insight into the workings of the Turing/Welchman Bombe and an
understanding of menus, how they were run and how the results were
If you have found this interesting I suggest you try breaking some
real messages which will shortly be going up on codesandciphers.