BLETCHLEY PARK RESEARCH PAPERS
This page contains previously unpublished technical research reports written at Bletchley Park during World War Two by some of the key codebreaking figures. These papers consist mainly of proposed improvements to the variants of the British Bombe Machine, a key tool in the breaking, on an industrial scale, of the German Enigma system. Research and development was a key part of the Bletchley Park operation during World War Two. When the Bombe machines were put into production, Hut 6 and 8 staff were continually looking for new ways to exploit and improve their operation. These research papers were written by Hut 6 and Hut 8 staff between 1940 and 1944. While a number of the ideas proposed were never put into action, they do show the innovative thinking which was encouraged in both sections.
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Gordon Welchman
9 September, 1940
Describes the operation of a ‘Bombe’, a ‘Spider Bombe’ and a ‘Hand Bombe’. Other tools described include a ‘Turing attachment’, a ‘Welchman attachment’, a ‘machine gun’, ‘shortening plugs’ and ‘cut-out wheels’. It sets out some of the problems faced by Hut 6 and Hut 8 staff and gives a statement of their requirements.
Gordon Welchman
Autumn 1940
Describes the number of ‘Spider Bombes’ needed to deal with the problems faced by Hut 6 and Hut 8. It estimates that between 50 and 60 machines are needed and recommends that all BTM (British Tabulating machine Company) work should be devoted to the ‘Spider Bombe’.
Gordon Welchman
Autumn 1940
Describes the operation of the ‘Spider Number 3’ or ‘Jumbo Bombe’ with three diagonal boards. It also describes the function of the ‘sensing relays’. It contrasts this to the ‘Standard Spider Bombe’ and the appropriate use for each variant of machine.
Gordon Welchman
Autumn 1940
Describes ‘Banbury Jobs’ which involve the use of two inputs for each bank of drums on the Bombe. It also describes the use of a ‘circuit breaker’ in the ‘sensing relay’.
Gordon Welchman
Autumn 1940
Describes a new method of attack against Enigma and encourages staff in the Hut 6 Machine Room experiment as much as possible. This applies particularly to problems with the ‘Brown’ key. It describes a process called ‘running a tape’ and ‘count letters’ in decoded messages.
6. Organisation of Bombe Section
Elwyn Jones
22 May, 1941
Describes the organisation of the Bombe sections in Hut 11 at BP and at Wavendon. This includes processes in place and timings for specific jobs and maintenance tasks.
Oliver Lawn
1941
Evaluating the chance of any ordinary straight on a ‘Jumbo Bombe’ involving one, two, tree, etc self-steckers.
8. A wiring for a 676 relay machine
Lionel Clarke
1941
Looks at non-energised points of the main chain rows during a run.
9. Proposal for a slightly different design of testing Enigma
Oliver Lawn
1941
Proposes a wiring very similar to the X – machines, except that the wheels are side by side instead of gripped together.
10. Note on possible development
Gordon Welchman
1 September, 1941
General description of various current methods of solving a key and problems with different Bombe configurations. Makes several recommendations.
11. An idea for the ‘Super Jumbo’
Oliver Lawn
12 September, 1941
Considers implications of the ‘Super Jumbo Bombe’ having 676 relays, one to each point of the diagonal board.
12. Second note on possible developments
Gordon Welchman
19 September, 1941
Proposes the use of a one bank ‘Jumbo Bombe’ which is called a ‘Baby Jumbo’ and considers its use on ‘full range’ problems where 17,576 positions per wheel order needed to be tested and ‘short range’ problems’ in which only a few positions need to be tested.
Gordon Welchman
12 September, 1941
Current problems are described along with a proposal to introduce three new machines: a ‘super test plate’, and two machines of the bombe type but with refinements which will save running and testing time. The names ‘Mammoth, ‘Baby Jumbo’ and ‘The Quagger’ are given to the machines.
14. Third note on possible developments
Gordon Welchman
22 September, 1941
Refinements to the proposals in paper 12 are described.
Oliver Lawn
October, 1941
Considers possible ways of running a given menu on various machines including: ‘Ordinary Jumbo’, ‘Mammoth B’, ‘Mammoth A’, ‘Baby Jumbo’.
16. Interim report on developments in mechanization
Oliver Lawn, Nigel Forward
October, 1941
Discusses the current position with different Bombe variants and how various menus would be run.
17. Report on ‘Intelligent Selection’ by the Junior Sub-Committee of Mechanization
Nigel Forward
October, 1941
Describes the method of intelligent selection and compares it with more rigid methods.
18. Notes on impossible developments I
Author unknown (listed as D.B.S.)
17 November, 1941
Describes the idea of running two short cribs and comparing the stecker given, first with two or three fixed letters and then with the rest.
19. Notes on impossible developments II
Author unknown (listed as D.B.S.)
17 November, 1941
The theory given in paper 18 and a calculation of how many consistent pairs of stories we expect.
20. Notes on impossible developments III
Author unknown (listed as D.B.S.)
17 November, 1941
Papers 18 and 19 continued and discusses the possibilities of using short beginners (or endings) and reasonable menus.
21. Notes on impossible developments IV
Author unknown (listed as D.B.S.)
17 November, 1941
Describes a mechanical method of sorting various sets of steckers punched on two cards so that two cards are brought together if they have on them sets of non-contradictory steckers.
22. Notes on impossible developments V. Application to present work
Author unknown (listed as D.B.S.)
17 November, 1941
The ideas in papers 18-21 are applied to new developments with the Red key.
23. Banbury bombe with applications to Wehrkries
Author unknown (listed as D.B.S.)
18 February, 1942
Description of how to use the right hand wheel and possible middle wheel at the ‘testing’ or ‘machine gun’stage.
24. Note to Gordon Welchman and Harold Fletcher
Oliver Lawn
16 March, 1943
Note suggests several minor alterations be made soon to the panned alterations and improvements to the ‘Mammoth’ and ‘Jumbo’ Bombes.
25. Permuted wheel orders
Oliver Lawn
27 July, 1942
An account of the methods of fitting a permuted wheel order device on a Bombe.
Oliver Lawn
8 September, 1942
Specification of a ‘Baby Jumbo’ with an account of what the Hut 6 team want it to do.
27. Double inputs on ‘Fortress’, ‘Kanga’ and ‘Warspite’ type machines
Author listed as Warrant Officer, R.A.F., Head of Section, Hut 11
18 March, 1942
A description of the method of scanning, testing and printing which occurs on Warspite and Fortress.
28. Hoppity transcended (Peggity or non-stoppody)
Nigel Forward
Autumn, 1942
Describes how if the ringstellung is known, use can be made of the fact that any particular position for the encoding of a message implies a particular value for the message setting.
Gordon Welchman
Autumn, 1942
Presents ideas about ‘High Speed Bombe’ (produced entirely by Keen and recording stops); ‘Super High Speed Bombes’ (same as previous machine but with Wynn Williams attachment); ‘High Speed Mammoth’ (produced entirely by Keen and recording only stories, ie stops which involve no contradictions); ‘Super high Speed Mammoth’ (same as previous machine but with Wynn Williams attachment).
30. Resistance method of Mammoth sensing
Joseph Eachus
15 October, 1942
Suggests that Mammoth testing may be done with relatively little additional equipment if we depend on the sensing relays of the bombe for the detection of straights.
31. Report on four wheel Bombes
Gordon Welchman
31 October, 1942
Describes the main requirements and the relative merits of valves and relays. Reports on developments at BTM, by Flowers on input sensing and Wynn Williams ‘Cobra’ attachment.
Oliver Lawn
5 November, 1942
Describes how the Bombe looks for a ‘partial key’ and a possible discrepancy between what the Bombe is looking for and what the crytanalysts are looking for which makes certain ‘partial keys’ inherently more likely to be correct than others.
Lionel Clarke
Autumn 1942
Describes a Bombe running known stecker jobs with plug-in contacts to make specific connections and 12 inputs.
Oliver Lawn
12 December, 1942
Examines the time taken to run various menus and the merits of running a stroner menu on two banks only.
35. The ‘Orange attachment’ to a Bombe
Oliver Lawn
29 December, 1942
Proposes methods for plugging and using a known stecker. Two schemes are described along with how they would work on certain problems.
36. Bombes (a note to Commander Travis)
Gordon Welchman
11 April, 1943
Describes how general lines of policy are becoming fairly clear and that concentration should be on the best use of Bombes for three wheel jobs. Recommends lawn’s method for using a batch of five M4 machines.
37. High speed Bombes for three wheel jobs
Gordon Welchman
28 March, 1943
Describes how to make best use of high speed Bombes for three wheel problems until they are needed regularly for four wheel problems.
Oliver Lawn
Spring 1943
Describes how menus are sent via telephone.
Oliver lawn
4 June, 1943
Describes jobs with ringsettung cut-in and stecker knock-out are sent to Hut 11A to simplify plugging.
Oliver Lawn
24 June, 1943
Tips and hints for menu making.
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Oliver Lawn
16 October, 1943
Describes the machine which consists of the right-hand wheel and stecker of eight enigmas and the theory of its operation.
Oliver Lawn
16 October, 1943
Describes the function of the test plate, an electrically driven enigma with separate stecker boards for the input and output.
43. Application of ringstellung range to Bombe
Autumn 1940
John Herivel
The first description of hoppity using rignstellung ranges and an estimate of the time saving involved with such a method.
44. Sensing on the B.T.M. high speed machines
Gordon Welchman
August 1943
Describes the timing of the pulsing gear and circuit breakers on the high speed Bombe and the improvement offered by a commutator design change to enable a continuous pule.
45. ‘One self-stecker’ sensing
Oliver Lawn
30 August 1943
Describes two single input methods and one double input method giving single input stops.
Hugh Alexander
Summer 1943
Describes how to exploit the tendency on 4 German naval keys for letters close together to be stickered together.
Oliver Lawn
23 August, 1943
A statement of when it is worth making a short crib into a delayed hoppity rather than running a lot of menus.
Oliver Lawn
24 August, 1943
A stamen of the use of 2 x 4-wheel high speed Bombes of the ‘Cobra’ type and 11 x 4-wheel Keen Bombes on 3-wheel jobs.
Oliver Lawn
4 September, 1943
Describes the albatross stecker which has ‘fixed stecker distances’ for each day and how to make up menus to deal with it.
Joseph Eachus
Describes the American naval Bombes with details of carry, etc but not of carry.
Oliver Lawn
23 August, 1943
Description of the two sensing racks used with ‘Cobra’ Bombes.
52. Breaking on the two-wheel Bombe
James Aitken
Description of the method of ‘column menus’ when a long crib is available along with a note by Oliver Lawn on changes to the Bombe required by the method.
53. Preparation of material before sending to Hypo
Author unknown
March, 1944
Description of the way Hypo works and the procedure for preparing jobs.
Hugh Alexander
15 February, 1944
Statement of the problem and of a possible method of attack which is the basis of the Duenna idea. Includes a covering letter to Welchman.
55. Method for testing ‘Holmes Hypothesis for U.D.
Hugh Alexander
14 April, 1944
A proof that (i) no two of the known D’s (1-9) are at a distance 13 on the Holmes Hypotheses and (ii) the D’s are not equally spaced on the Holmes Hypotheses. Uses the method of boxing.
Oliver Lawn
25 May, 1944
Description of how the ‘Clarke test number’ is worked out gives a table of values.
Image: Early staff list for part of the fledgling Hut 6 at Bletchley Park.
